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Powerboater`s Guide to Electrical Systems, 2nd Ed

1. Fig 11 17 Amp hour calculation table for determining the correct size of an inverter battery bank engine s alternator while underway If you expect to be using this system for weekend jaunts at anchor you must multiply everything by two If you expect to be away from shore power for a week multiply by seven and so forth Once this is done go back to chapter 5 and refer to figure 5 2 on page 71 which shows typical battery amp hour ratings Take a com mon group 27 battery for example It has a typical amp hour rating of about 105 amps You can only use a little over 50 of these to prevent excessive bat tery discharge so if your daily consumption requires 100 DC amps you ll need at least two of these group 27 batteries for each day away from the dock Figure 11 18 shows two formulas for determining battery bank size based on known amps or watts Figure 11 19 lists some common AC appliances and their approximate wattage ratings Installing an Inverter After determining inverter and battery bank sizing you may be considering the possibility of installing an inverter on your own The truth is to install all but the simplest inverter with its own self contained plug outlets goes well beyond the scope of this book and certainly the abilities of the average boatowner There are many considerations to make and even ex perienced electricians often overlook some of the fine points of the ABYC s recommendations for inverter i
2. Circuit Protector Battery iid 4 ally there is a third type but it s really only a combination of the first two called appropriately enough a series parallel circuit A clear understanding of what hap pens in each of the circuit types as electrons flow through them will go along way toward helping us to think out problems which will undoubtedly arise later Let s take a close look at these three types of circuits one at a time but first we need to understand the differ ences between marine circuits and others such as those found in Load Fig 1 1 The basic circuit showing the key elements your family car Marine versus Automotive Circuits One of the most common mistakes that many proud owners of new powerboats make is to try to save a few dollars by installing inexpensive automotive acces sories in place of more expensive marine accessories After all it doesn t really matter if that new reading light in the forepeak is designed for a boat or an RV does it I mean a light is a light right Wrong Even the best made and most costly automotive accessories are not really appropriate for installation in boats not so much because of the accessories as because of the circuits to which they will be attached Most automotive equipment is made from mild steel or will have major components made from some highly corrosive material but this is not what con cerns us here If you take a close look at
3. Circuit Protector Load Cabin Light Battery Fig 3 13 Basic ammeter series hookup Remove the fuse and attach the meter leads as shown all the circuit s power supply must then flow through the meter once the circuit is turned on Here the meter measures a 2 A current draw by the cabin light mo A 0 UM 0 9 5 E Fig 3 14 A meter showing a 1 and 20 amp socket The l amp socket would be used to measure milliamps series with the circuit If you have probes on your meter leads you ll find this test much easier if you go out and buy a set of leads with alligator clips on the working end of the leads First make sure the cir cuit is turned off and that your meter is turned on and set up properly Double check to make sure that the red lead is plugged into the socket for 10 or 20 amps if your meter has one Now disconnect a wire at the point where you wish to measure the amperage and clip the black probe to the terminal that is closest to the battery Clip the red probe to the remaining terminal Figure 3 13 illustrates this basic hookup The meter s leads must be in the appropriate socket for the level of amperage being read Meters with the ability to measure both milliamps and whole amps up to the 10 or 20 amp level may have sepa rate sockets for the red test lead as shown in figure 3 14 The black lead will remain in the COM socket If your meter is self scaling you ll have to se lect between
4. Protection at Source of power Distribution panel panelboard or switchboar Source of power battery Fig 4 16 Without a submain breaker this panel has none the feeder protection should be rated at no more than 100 per cent of the feeder ampacity ABYC Wire and Circuit Protection Standards and Repair Procedures The 7 40 72 Rule The 7 40 72 rule of the ABYC s standard E 11 is en titled Overcurrent Protection and states Ungrounded conductors positive power feed conductor shall be provided with overcurrent protection within a dis tance of 7 inches 175 mm of the point at which the conductor is connected to the source of power mea sured along the conductor That means that the fuse or circuit breaker must be located no more than 7 inches from the battery There are some exceptions to the 7 40 72 rule as follows pm Starter motor circuits are exempted from overcurrent protection within a distance of 7 inches 175 mm of the point of connection to the DC electrical system or to the battery This means that if the charger is connected to the battery and sheathed or enclosed the fuse or circuit breaker can be as far as 72 inches away 1 83 m from the battery If the wire is sheathed the 40 inch rule ap plies as long as the wire is not connected directly to the battery One additional exception that applies to many newer powerboats is that no fuse or circuit breaker
5. voltage drop criterion and referring to figure 4 3 on page 44 you can see that the correct wire to use is 14 AWG By using the ampacity table figure 4 7 on page 48 you can see that 14 AWG wire has an am pacity of 35 amps outside the engine room and just under 30 amps inside the engine room Well in this example even though the actual load is only 5 amps we have connected the load to a wire with a base ampacity of let s say 30 amps we ll use the engine room rating here We could use a circuit breaker or fuse rated as high as 45 amps 150 percent of 30 and provide adequate protec tion for the circuit s wiring However we don t need that much protection and in this case a com mon 10 amp breaker or fuse would be quite ap propriate and would provide safe conservative protection for the circuit Remember when in stalling overcurrent protection it s the circuit wiring you re protecting Any protection for the equipment the circuit is supplying will be done at the equipment with the exception of motor loads as discussed in chapter 4 which may be internally protected but in fact usually is protected by a fuse or breaker in the circuitry This explains why most electronic equipment has an individual fuse in addition to the fuse or circuit breaker on the circuit The main fuse or circuit breaker on each circuit is there to protect the wiring that s common to all equipment on the circuit and the internal fuse is there to prote
6. voltage regulation Maintenance of voltage output despite variation in output current within engi neered parameters watt A unit of power The English unit of mea surement is the horsepower which equals 550 foot pounds per second or 746 watts waveform Voltage as a function of time of a re curring signal The waveform of AC voltage is the sinusoid much like that of an ocean wave wet cell battery A typical cranking or deep cycle battery as compared to a dry cell flashlight bat tery Wet cell batteries can be recharged most dry cells cannot 199 200 Resources A number of products and tools are mentioned throughout the Powerboater s Guide to Electrical Sys tems In most cases your local marine store or chan dlery has or can get you the equipment we ve discussed Here are some other useful resources Blue Sea Systems A great resource for parts as well as technical advice Call 1 800 222 7617 for customer service or 360 738 8230 for the technical support line or go to www bluesea com Boat U S Check them out at www boatus com or call 703 461 4666 Boater s World Call 1 877 690 0004 or visit their website at www boatersworld com Defender Industries Call 1 800 628 8225 or go to www defender com MAC Tools Corp MAC distributes through local franchised mobile vendors To find a dealer near you go to www mac tools com or call 1 800 622 8665 NAPA Auto Parts Stores NAPA has an excellent line
7. ClBVISION ESTER 80 100 MPa MEUS tr A OR E R N 50 E E A rd E TAN 50 CUTTING TONE eek a eee lace thn E A 50 AIITEM Er Fee C E 100 Blender e due eoe e no 300 AINON A RSS 500 Orbitalsandern a a E A 500 Veenker e extn ee oe A A IDE 200 Small refrigerator 2 2 sooroo eee eee 150 Mid size microwave 0 00e00ee 900 Hand held vacuum 00000 1 100 HaltsidiVeriees ts hae om e S 1 500 Fig 11 19 Common AC appliances and their wattage re quirements gine room Further complicating the issue is the fact that manufacturers of inverters prefer to have them mounted as close to the battery bank feeding them as possible The reason for this is to minimize the effects of voltage drop in the DC feeder wires to the inverter Minimal voltage drop is a must if the unit is going to achieve the 90 percent efficiency mentioned ear 173 174 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS lier Batteries give off explosive hydrogen gas when being charged and so need to be well ventilated to remove this gas Mounting an inverter close to batteries in an un ventilated compartment such as under a V berth is not a good choice unless adequate ventilation is added to create sufficient air exchange Also the in verter itself is heavy and must be securely mounted to a panel or bulkhead Inverters must be kept cool to keep the efficiency up and to ensure the long life of the inverter itself So again the ventilat
8. a 20 watt bulb on a 12 volt circuit will draw 1 7 amps 20 12 1 7 Once the amperage is known measure the dis tance of the run from the distribution panel to the new fixture and back again A quick reference to the table will give you the wire size to use for the job Since this is a cabin light you should use a dark blue wire to the light and a black or yellow preferably yel low wire for the return to the panel One precaution regarding fixtures of this type Often a manufacturer provides a short length of wire lead from the fixture to facilitate attachment to your Installing Your Own DC Accessories wiring harness or new circuit Typically these leads will be 16 AWG Regardless of which gauge wire you select to run from your distribution panel to the new fixture you must always rate the circuit overcurrent protection at the ampacity of the smallest wire in the circuit In this example it would be the 16 AWG wire supplied with the fixture assuming you use a 14 AWG feeder and ground return wire for a long run Step hy Step Instructions So with the basics above in mind my step by step approach to adding a new cabin light looks like this 1 After selecting a light fixture you like and mak ing sure that the voltage is the same as it is on your boat find the wattage of the bulb 2 Once the wattage is known determine the am perage requirements for the fixture In the above example a 12 volt 20 watt bulb would requ
9. 0 e eee eee eee 69 Battery Sally soer trario E tiie oot Ease pU eS EPOD 72 Battery Maintenance and Testing 0 0 c eee eae 74 Battery Installations 0 cece cece ee eee ee 76 Testing Your Batteries 0 cece n 82 Chapter 6 Battery Charging Systems 86 Alternator Basics eem e t RR Ip brow ene i nE Ei 86 Engine Driven Marine Alternators 0 eee 87 Alternator Problems sees 87 Outboard Engine Charging Systems 00 00000 94 Shore Power Battery Charging Systems and Installations 96 Solar Cells esenses s e RR a E ERR ear EDU LP ee cannes 99 Chapter 7 Maintaining Marine Ignition Systems 100 Ignition System Components lee 100 Regulations Regarding Ignition Systems 00005 103 Outboard and PWC Ignition Systems 000008 103 Maintaining Ignition Systems 6 c cece ee eee eee eee 104 MerCruiser Thunderbolt IV and Thunderbolt V Systems 107 Beyond the Basics Outboard and PWC Ignition Systems 110 Outboard and PWC Ignition Tests 0 0 cece eee ee 112 Testing Your Stop Switch 1 0 0 eee eee eee 119 Final Checks and Ignition Timing 00004 120 Chapter 8 Tracing and Repairing Starter Motor Circuits 123 Coast Guard Regulations for Starter Motors 4 123 Starter Motor Problems and Solutions 0 124 T
10. Dedication To my wife Nancy and son Mason who have to put up with me when I m involved in projects like this Copyright O 2000 2007 by Edwin R Sherman Click here for terms of use For more information about this title click here Contents Foreword to the Second Edition by Skip Burdon President and CEO American Boat amp Yacht Council vil Preface to the Second Edition 0 0 0 e eee eens ix Inttod ction esie eerieeb n ERN HR EI e ee eec e due x Chapter 1 Electrical Basics You Need toKnow 1 What Is Electricity cess eeeecec rere co hee prex news 1 Electrical Circuits cicer rr Rep ERR Eten ks 1 Ohm s Law and What It Can Tell Us 0 0 eee eee 5 Voltage Diop reer saa u ra Enn e ed e urs s rare US e ne levee 8 Putting It All Together 0 eee eee e 9 Circuit Problems and How They Occur 00005 9 Tools 2 csaaesindens ig scnaneods sales NET ERE ana 10 Chapter 2 Working with Wiring Diagrams 12 The Trouble with Boats cc cece cence eee eee eee eeee 12 Witing Diagrams i ssa esee hr e yes OU Wee ve UOS Sw reg 13 Common Symbols 0 ccc cece eee eee eee eee 13 Component Identification cee eee ee eee eee 14 Wire Identification and the ABYC Color Code 15 Expanding the Basic Circuit 1 0 0 0 0c eee eee eee eee 19 Locating Components 6 cece eee eee eee eens 20 Drawing Your Own Wiri
11. Ed wiggle test 169 170 shore power battery charging systems 96 99 short circuits 9 10 39 shorts to ground 9 10 106 117 shunt meters 28 silicon controlled rectifier SCR 104 silicone sealers 109 sine waveform 175 single pole AC circuit breakers 163 164 165 single sideband SSB radios 182 191 slave relays 125 slow blow fuses MDL or T 48 49 141 174 smart chargers 96 97 99 Snap On amp gauges 28 29 inductive ammeter 11 inductive meters 128 spark tester 11 113 Society of Automotive Engineers SAE 41 42 52 solar cells 99 soldering battery cable ends 60 terminals 59 64 solenoids outboard engine 134 35 starter 125 28 126 127 spark testing for 112 13 spark advance 106 110 spark control 109 10 spark plug gapping tool 112 INDEX spark plugs 103 106 112 checking 106 107 testing 113 14 spark plug wires 115 spark testers 11 113 speakers installing 145 46 specific gravity 83 84 sponge lead 65 standards See under American Boat amp Yacht Council ABYC Standards and Technical Infor mation Reports for Small Craft ABYC 32 41 starter motor circuits 124 125 diagnostics 124 25 engine ignition switch 133 35 134 neutral safety switch 128 129 130 132 33 outboard engine 128 32 129 130 131 troubleshooting 125 28 126 127 starter motors current requirements for 127 28 diagnostics 124 25 135 U S Coast Guard regulatio
12. Ifa golf course is not laid out just right nobody will play on it and if a golf club isn t built just so no one will buy it Remarkably no such basic standards ever devel oped for the people and companies that built plea sure boats It s true that industry leaders like Chris Craft Owens Penn Yan and many others built quality products to their own standards that were an excellent value for their customers How ever some builders produced shamefully shoddy boats that were not only a poor value but dangerous as well One New England manufacturer of open fishing boats for example built hundreds of boats with particleboard decks and transoms that liter ally melted once water penetrated the paint job An other company in California became famous for building boats with fiberglass hulls that were so thin that you could read a newspaper through them 40 The U S Coast Guard has a long list of safety reg ulations that apply to recreational boating but few of these standards applied to the construction of the boat That bassboat with the particleboard decks for example had a legal limit on the number of people it could carry and the horsepower of the outboard it could use but not a word was ever said about the integrity of the basic construction Finally out of frustration with fly by night builders and a growing accident and fatality rate that was giv ing recreational boating an increasingly tarnished im age the indus
13. James 6 wattage 7 9 and AC 160 AC appliance requirements 173 load analysis sheet 171 172 watts 5 6 7 8 waveforms 157 175 West Marine 62 68 136 180 wet cell batteries 67 68 69 72 73 wiggle test 169 170 windings field 86 stator 86 wire connectors 60 61 62 63 64 wire identification ABYC color code 15 17 circuit identification 17 19 wire size AC 160 61 162 AWG standard vs SAE stan dard 41 42 and circuit breaker sizing 137 38 for DC accessories 137 for electronic equipment 182 manufacturer s recommenda tions 55 143 rounding up 43 144 selecting 42 43 and voltage drop 43 44 45 137 144 wire stripper 11 62 143 wire ties 18 59 60 wiring AC 160 62 161 allowable amperage for con ductors 46 48 161 163 INDEX circuit identification 17 19 color coding 15 17 18 19 158 59 ignition 103 insulation standards 43 46 47 48 161 162 163 junction boxes 20 22 length for DC accessories 137 locating 21 22 panel feed 138 162 routing and support 57 59 securing 141 spark plug 115 standards for 40 59 types 41 42 137 wiring and connection repairs 59 64 strippers 11 62 143 wiring diagrams bilge blower 21 bilge pump 143 cabin lights 140 CD player 146 component identification 14 15 for DC accessories 138 DGPS receiver 190 191 double pole AC circuit breaker 164 drawing your own 22 24 elements of
14. My purpose here is not to attempt to show you every possible arrangement of batteries and selector switches but to give you a good understanding of the key elements in some of the most popular circuits Modification of these basic sys tems into more complex designs should not be too difficult once you understand the basic circuits The Guest Co a major supplier of battery switches and components now part of Marino has some ex cellent diagrams available that could be quite helpful if you do decide to undertake a major system upgrade on your boat Some examples of these diagrams follow in this chapter Battery selector switches have a continuous and an intermittent sometimes called momentary rating for amperage The continuous rating is the amperage the switch can sustain while the switch is in normal use The intermittent rating is the much higher am perage that a switch can sustain over a short period of time usually measured in seconds It s important to know what these ratings are when you purchase switches for replacement of existing switches or for additions to your system You can t tell much by sim ply looking at the switch The battery switch you select must be capable of handling the extreme intermittent current associated with engine cranking and the maximum continuous current of the electrical loads in your system Rating numbers look something like 230 amps continuous and 345 amps intermittent Heavy duty switches of
15. Pump 8 allowed by the sizing chart in figure 4 7 My advice here is clear for warranty and liability reasons as well an electric drill with an assortment of drill bits as your own peace of mind whenever there is a dis agreement or conflict among different sources of in formation always go with the recommendations of the manufacturer even if it seems like overkill Re member a wire that is too heavy will never do any harm up to a reasonable point of course whereas a wire that s too small can destroy your boat Figure 9 7 shows the diagram that comes with a popular pump assembly available from Rule Industries The pump motor shown here is like most bilge pumps polarity sensitive Reversing the positive and ground return wires on the pump motor will cause the pump to run backwards Most bilge pumps but and pump assembly bm asmall saw either a hole saw or an electric jigsaw depending on how you decide to mount your mas ter switch to cut out a hole for the switch panel Last but certainly not least you ll need a wiring diagram to help you lay out your new bilge pump circuit All of the major manufacturers of bilge pumps and switch panels supply this vital informa tion as part of their installation instructions They ll often include a recommended wire gauge to use for a certain length of wire run saving one step in the in stallation process However I have noticed that the recommended wire size provided by some m
16. When replacing an alternator belt exactly match the new belt to the old one Belt profile is just as im portant as the length of the belt There are differ Battery Charging Systems p 4 y Fig 6 2 Checking belt deflection This belt is adjusted just about right ences in the V on various belts as well as the actual belt width at the outer edge These dimensions must be correct so that the belt makes a tight fit into the pulley V to minimize slipping and to ensure long belt life Figure 6 3 on page 90 shows the correct pat tern for a properly sized belt Make sure all the pulleys used by the alternator belt are aligned in the same plane Any misalignment will rapidly wear away the belt and scatter black residue from the deteriorating belt all over the en gine Misalignment must be corrected to ensure long belt life Align the pulleys by shimming the alternator mounts until all are in perfect alignment POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Fig 6 3 Proper belt profile in the pulley Alternator Adjusting Mounting Bolt Alternator Mounting Bolt Fig 6 4 Alternator mounting and adjustment bolts typical locations To replace an alternator belt loosen the bolts in dicated by the arrows in figure 6 4 Pivot the alterna tor toward the engine remove the old belt and slide the new one in place Adjust to the correct tension not tighter Belts that are overtightened
17. Your inverter will need to have the power to deliver at least 2 500 watts in this scenario the smaller 1 000 watt inverter simply won t do the job Alternating Current and AC Equipment Determining the AC wattage you need is easy As already stated wattage or possibly volts and amps must be indicated on the appliance If the value is given in volts and amps simply multiply the voltage by the amperage to determine the wattage of the ap pliance Make a list of all the appliances you intend to run with the inverter and pay particular attention to the subtotals of gear you expect to run simultane ously If money is no object simply add up the wattage for all the appliances you expect to use Size your inverter to handle all the possible loads you ll run simultaneously The bottom line here Don t cheat Remember as already stated people tend to underrate their AC us age buy too small inverters and end up disap pointed after all is said and done This can t be emphasized enough Figure 11 16 on page 172 shows a sample wattage load analysis sheet for determining the size of the inverter to select based on wattage Next you ll need to make some decisions about how many hours each day you ll be running the var ious appliances listed in your inventory This will help determine battery bank size You must also take into account the loss through the inverter as it performs its magic This loss is really a form of volt age drop and
18. breaker installed either The latest version of the ABYC s electrical standard E 11 states that A battery switch shall be installed in the positive conductor or conductors from each battery or battery bank with a CCA rating greater than 800 amperes You ll have a lot more information on batteries and battery banks in chapter 5 For the moment suf fice to say that many small runabouts with only one small battery could easily fall below this 800 amp threshold and would be exempt from the recommen dation for a battery switch I should also point out that even though switches are not recommended for these Working with Wiring Diagrams Negative Bus Bars A Circuit Breakers Sti Positive Bus Bars AT Bilge Blower Showing positive and negative E l return wires through switch panel i Fig 2 6 A bilge blower circuit highlighted on the switch panel with the key components identified When looking at large clusters of wires in an arrangement like this it s impor tant to focus on only the components and wires that are im portant to you at the moment To begin your search start at the wiring at the back of the switch or breaker labeled blower in this example and carefully tug on the wire to fol low it through any bundling at the back of the panel Once you ve identified all the wiring behind the panel locate the component in question on your boat A good wiring diagram may indi
19. close inspection shows a terminal that s completely engulfed in the stuff First make sure the blower switch is turned off Then remove the terminal with a screwdriver then a quick scrape with your trusty pocket knife takes care of the corrosion Once the ter minal is cleaned and reattached the blower is as good as new and you re soon blasting over the waves thinking of nothing but pepperoni mushrooms and mozzarella cheese The day is saved and instead of a schmuck you re a hero Plus you probably saved yourself enough in repair bills to at least pay for the pizza Figure 2 6 on page 19 illustrates what you must focus on when confronted with an electrical problem of this magnitude The highlighted areas of this drawing are the only things you should be thinking about as you try to troubleshoot a problem with this bilge blower circuit Looking at figure 2 8 you can see what this might look like on a typical wiring dia gram the dotted line represents the proper circuit with each element of the circuit identified Track down and check out each of the basic elements de scribed in chapter 1 and you ll quickly locate the trouble with any circuit Locating Components A common trick for boatbuilders especially on mid to larger sized boats is to install remote junction boxes for wiring They really do this to simplify the electrical system and to save money on wiring but it Working with Wiring Diagrams NOTES 1 2 S
20. for example will function at the 10 percent maxi mum voltage drop but with a considerable loss in light intensity for a given bulb wattage Use the charts provided in chapter 4 to help you through this decision on voltage drop and wire size My recommendation is that unless you re on a very tight budget you follow the example of the high end builders and use a 3 percent voltage drop for every thing You can t go wrong Wire Type Once you have determined the gauge of the wire you ll need in your new circuit think about the wire insulation requirements and again refer to chapter 4 for help determining what s required Installing Your Own DC Accessories A time saving alternative to running separate wires for the hot and ground sides of your new piece of equipment is quality marine grade duplex wire that has the two conductors bonded together much like a household extension cord Household wire of course should never be used on a boat the insu lation is not rated for the marine environment Du plex wire has a double layer of insulation and it s much easier to fish through small holes and tight places than individual wires A single run of duplex wire is slightly more expensive than a double run of single wires but usually not enough to offset the con venience and other advantages it offers If you re trying to match ABYC color coding rec ommendations you might have trouble finding du plex with the correct colors for the c
21. however is that our friends at the ABYC have developed a standard color code for boat wiring that brings order to this previously mind boggling task This color coding scheme which has been around for twenty odd years is finally catching on The ABYC color code assigns a specific color of wire to each function in a properly wired marine electrical system Thus an electrician who is work ing on a boat wired to the ABYC standard and is con fronted with a dark blue wire knows immediately that that wire is for the interior lights and nothing else He or she also knows that the purple wire is for the ignition system and that all those red and yellow wires are the DC positive and negative connectors This standard makes it easy to identify a wire s func Negative Bus Bars Circuit Breakers Switches Positive Bus Bars tion in the system on any boat not just your own even without the help of a wiring diagram Fig 2 4 A switch panel with key components identified 15 16 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Black or yellow WIRING COLOR CODE Color Use Green or green DC grounding w yellow stripe s conductors DC negative conductors COLOR Red DC positive conductors ITEM ENGINE AND ACCESSORY WIRING COLOR CODE USE Yellow w red stripe YR Starting circuit Starting switch to solenoid Brown yellow stripe BY or Yellow Y see note Bilge bl
22. or amperage to work with For example if you wanted to measure the value of a resistor with a me ter that did not have self scaling and you set the meter to the wrong scale you would get a grossly incorrect reading For certain functions such as amperage and voltage if you set the scale incorrectly you might blow a fuse in the meter or even damage or destroy the me ter With self scaling the danger of selecting the wrong scale is greatly reduced even though you must still be careful selecting the function Diode Checking The diode check function as found on most of the better multimeters is really only an ultrasensitive and highly selective section of the resistance scale but it s a useful feature that adds virtually no cost to the meter Although it s possible to check some diodes with a meter that does not have specific diode checking capability by setting the meter to the lowest ohms scale the reading that results should never be counted on as accurate To check a diode with a diode checking meter you test for continuity see below in one direction then re verse the probes and check again in the other di rection If the diode is working properly you ll have continuity in one direction and not in the other Diodes need a certain amount of current flowing through them to function and the internal batter ies of many meters without a diode check function don t provide enough current in the ohms scale to close the diode Often
23. selecting the correct size of wire to use is simply a matter of working the numbers found in figures 4 3 and 4 4 on pages 44 and 45 Let s try out figure 4 3 You ve decided that you re dealing with a critical circuit and will use the 3 percent maximum voltage drop value Yours is a 12 volt boat and you know that the pump in question draws 5 amps and that 20 feet of wire separates it from the panel board supplying the pump A two way run would mean a total conductor length of 40 feet Find the 40 foot column on the chart and correlate it with the 5 amp row in the 12 volt section You should find a 10 gauge wire size recom mendation Keep in mind that these two charts are de signed for sizing wires based on the ABYC acceptable voltage drops described earlier Don t confuse the 3 percent and 10 percent specifications And most important re member that the length of the wire is the to tal of the positive and negative sides of the circuit For example if a component is 12 feet from your distribution panel the length of the run will be 24 feet The column that most closely matches that on either of these tables is labeled 25 feet When a number falls between any two values always round up to the next highest number Wire Insulation Quality wire has a rather lengthy story written right on the insulation The writ ing on the wire can help you decide the wire s suitability for certain applications the maximum voltage for the wir
24. the heater and the heater or the element will have to be replaced Figure 11 15 shows this test being performed on a good element with a typical resistance reading shown on the meter Selecting a DC to AC Inverter Popular with the sailboat crowd for some time now 12 volt DC to 120 volt AC inverters are also be coming increasingly popular among owners of small powerboats The reasons for this trend are quite sim ple Space on small boats is at a premium so a gen erator installation is usually out of the question Cost At least for limited use the DC to AC inverter has changed the way many small boat owners satisfy their craving for AC power on board Engi neers have designed inverters that can produce as lit tle as 50 watts to as much as 3 000 watts of continuous power more than enough for most small powerboats ELECTRIC WATER HEATER Fig 11 15 A continuity test on a hot water heater element Selecting an Inverter Nothing comes without a price and although these electronic marvels are quite capable of producing ad equate AC power they need a fairly substantial DC power source to keep them running This in itself can be the limiting factor on some boats Batteries are heavy and they too take up space When selecting an inverter and designing the system that will sup port it there are some important considerations you must make to ensure your ultimate satisfaction Classically people g
25. 1 6 The ohm sym bol the Greek omega Let s forget about joules for now and take a look at each of these other terms more closely and per haps we can begin to get a clearer picture of their importance to us Voltage Voltage is the measure of the potential that an electri cal power source has for doing work for us Thus a fully charged 12 volt battery has the potential of pro ducing 12 volts actually closer to 13 5 volts of power In fact the term electrical potential is often used instead ofthe word voltage and means the same thing To refer back to the analogy of the water tank where a hose connected to the bottom ofa tank might measure 100 pounds per square inch psi of water pressure a wire connected to a 12 volt battery in a circuit of course will measure 13 5 volts of electrical potential In both cases we are referring to the energy that s available to do work and nothing else the voltage in the battery is exactly the same concept as the water pressure in the tank Simply think of voltage as electrical pressure The higher the voltage in the battery or in any other source of electrical power the more pressure is avail able to send electricity along its path in a circuit Amperage Amperage is often confused with voltage and I think it s the most difficult of all our definitions to grasp Think of amperage as the rate of electrical flow past a given point in a circuit If you can think of voltage as electrical p
26. 14 and 15 If your boat is wired to the ABYC s recommended standards you can get a jump start in deciphering what you see behind your distribution panel by using this table By now you may be saying to yourself Hey this is great but wait as I look behind my distribution panel I see 20 red wires and 20 yellow ones or black ones on an older boat and several each of about a dozen other colors What do all these wires do and which one feeds which circuit All you know from the table above is that the yellow or black wires are supposed to be DC negative conductors the red ones should be DC positive conductors green ones are ground wires and light blue ones are for the instru ments But as you sort through this spaghetti how do you tell just exactly what each wire does Your boat may not use the ABYC recommended colors in its wiring or it may only use some of them Also as with most changes initial acceptance of the color coding standard when first introduced was neither univer sal nor overwhelming Most manufacturers have im plemented the changes gradually as they updated their assembly procedures and as stocks of existing wire were depleted Also it s important to note that the ABYC standard allows for deviation from the rec ommended color scheme as long as all wiring is iden tified in some way Many builders have adopted a numbering scheme that positively identifies any wire with numbered labels affixed to the wire a wir
27. 165 174 Index panel feed wire 162 probe pen 11 safety with 157 58 shore power wiring diagram 159 160 wire size 160 61 162 wiring bundles 161 alternating current AC equip ment See also alternators DC to AC inverter selection 170 75 galvanic isolators 177 79 generators 172 175 77 176 testing resistive 170 alternators 86 87 engine driven marine 87 marine vs automotive 88 one wire 81 problems with 87 99 tachometer failure and 152 testing 91 94 American Boat amp Yacht Council ABYC amperage for conductors 46 48 161 163 basic wiring standards 41 46 battery cables standards 77 battery location standards 73 74 battery switch standards 19 certification program 158 color code standards 15 17 development of standards 40 41 fuses and circuit breakers standards 46 51 galvanic isolator standards 178 79 ignition protection 52 53 soldering terminals 60 temperature ratings standards 46 47 48 161 162 163 voltage drop and wire size standards 32 43 44 45 137 Copyright 2000 2007 by Edwin R Sherman Click here for terms of use wire and circuit protection standards 40 59 wiring and connection repairs standards 59 60 American Wire Gauge AWG 41 42 77 ammeters inductive 11 29 30 36 37 93 169 amperage 6 9 AC checking 169 adequate 27 28 allowable for conductors 46 48 161 163 charging test 93 DC accessory requirements 136 DC equipment draws 3
28. 181 potential 5 power formula 7 8 power supply circuit 20 power supply for electronic equipment 182 83 probe pen for AC 11 ProMariner galvanic isolator 178 179 pulsar coils 104 111 radar installation 191 92 radio frequency interference RFI 181 82 radios See single sideband radios transistor radios VHF very high frequency radios ratcheting crimper 11 61 62 63 143 rectifiers bridge 86 87 diode 95 96 silicon controlled 104 reference voltage 92 remote control engine ignition switch and 133 35 134 neutral safety switch 128 129 130 132 33 outboard engine starter cir cuit 128 129 outboard engine stop switch 119 20 repairs procedures 40 59 wiring and connections 59 64 resistance 6 9 156 measuring 37 39 resistive equipment checks AC 170 resistor type wiring 115 reverse polarity 159 ripple voltage test 93 94 Romex wire 41 162 164 root mean square RMS multi meters 11 26 30 157 rotor 86 108 109 safety AC 157 58 AC generator 176 battery 72 74 84 corrosion protection for igni tion systems 104 106 galvanic isolators 177 78 ignition protection 52 53 103 123 166 overcurrent protection 57 58 162 63 164 165 174 wire and circuit protection standards 40 59 safety goggles 84 schematic diagrams See wiring diagrams sensor coils 104 111 series circuits 2 3 4 series parallel circuits 2 4 5 7 40 72 rule 57 58 Sherman
29. 186 90 187 188 189 galvanic isolators 179 GPS receiver 190 91 inverter 173 74 magnetic field issue and 180 81 radar 191 92 RFI and 181 82 speakers 145 46 VHF radio 183 86 191 zone of magnetic separation and 145 181 182 instrumentation engine abnormal readings 148 49 future equipment 155 interpretation problems 147 48 troubleshooting 149 55 insulation flexible cords 46 wire 43 46 wiring conductors 46 47 48 161 162 163 intercircuit shorts 10 106 internal shorts 10 International Standards Organi zation ISO color coding 159 inverter battery bank sizing 171 73 inverter chargers 96 INDEX inverters 170 AC need analysis 171 73 installing 173 74 monitoring 174 175 waveform 175 J Joule James 6 joules 5 6 jumper leads 11 jumpers 108 junction boxes 20 22 knock retard spark control 109 10 L labels for circuits 17 18 lead wire 3 lead acid batteries See batteries light emitting diode LED charging system testers 93 94 light emitting diode LED out let testers 11 167 lights See cabin lights loaded voltage 92 loads 2 92 load test 84 85 Loctite 108 109 Loran 181 182 183 lugs vs terminals 77 magnetic circuit breakers 51 magnetic field issue 180 81 magnetic induction See induc tion magnetic separation zone of 145 181 182 Marinco 78 169 marine cranking amps MCA 71 72 marine vs automotive circu
30. 2 9 m suus 0 50 mm 9 5 12feet 2 9 3 7 m 2 2 eee 00 70 mm 12 15 feet 3 7 4 6m 000 95 mm 15 19 feet 4 6 5 8 m 0000 120 mm 17 78 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS combination of cranking batteries to start the engine and deep cycle batteries to run the boat s systems The longevity of these batteries will be greatly de creased if they are used for the wrong application so you need a means to select which battery is in use at the appropriate time The very best way to do this is with a battery selector switch with the familiar off No 1 No 2 and both switch positions These switches should be installed on any boat with an electric system even if you have only a single battery Of course a single battery installation doesn t need the four position switch A simple two position on off switch will do fine The ABYC recommenda tions exclude boats using batteries smaller than 800 CCA from the requirement for a battery isolation switch so if you buy one of these smaller boats you ll probably have to install the switch yourself Fortu nately it s an easy and straightforward job A recent experience I had brought home the im portance of being able to quickly shut down any boat s electrical system in case of emergency I was motoring across the bay when I noticed a small boat with smoke billowing out from under the port side d
31. 4 24 shows my crimper made by Ancor Fig 4 24 Ancor ratcheting crimper By using this type of crimper you can be assured that all your connections will be crimped properly as long as you use the tool correctly 61 82 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS For wire stripping I use the end type stripper shown in figure 4 25 This stripper is adjustable so that the exact amount of insulation can be removed from multiple pieces of wire and the risk of cutting into the wire strands is minimized Both the crimper and the wire stripper are avail able through West Marine and all the major marine supply stores At about 140 for the pair this combi nation is a really good investment and will make your work much easier Figure 4 26 shows the stripper in use and figure 4 27 shows the crimper in use About inch 6 mm of insulation should be stripped off the wire before it s inserted into the ter minal ferrule The stripper mentioned above allows you to set the amount of insulation to be removed in millimeters The correct match of wire and connector is illustrated in figure 4 28 The ends of the wire just barely protrude from the ferrule of the terminal Fig 4 25 End stripper I love these tools because you can ad just the amount of insulation to remove for a really good match to the crimp connector One drawback is that they only work on wire up to 10 AWG Fig 4 26 End stripper
32. AS TO THE ACCURACY ADEQUACY OR COMPLETENESS OF OR RESULTS TO BE OBTAINED FROM USING THE WORK INCLUDING ANY INFORMATION THAT CAN BE ACCESSED THROUGH THE WORK VIA HYPERLINK OR OTHERWISE AND EXPRESSLY DISCLAIM ANY WARRANTY EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE McGraw Hill and its licensors do not warrant or guarantee that the functions contained in the work will meet your requirements or that its operation will be uninterrupted or error free Neither McGraw Hill nor its licensors shall be liable to you or anyone else for any inaccuracy error or omission regardless of cause in the work or for any damages resulting therefrom McGraw Hill has no responsibility for the content of any information accessed through the work Under no circumstances shall McGraw Hill and or its licensors be liable for any indirect incidental special punitive consequential or similar damages that result from the use of or inability to use the work even if any of them has been advised of the possibility of such damages This limitation of liability shall apply to any claim or cause whatsoever whether such claim or cause arises in contract tort or otherwise DOI 10 1036 0071485503 9 Professional AC Want to learn more NL a aN We hope you enjoy this McGraw Hill eBook If you d like more information about this book its author or related books and websites please click here
33. Cahles In the latest version of the ABYC battery standard E 10 a major wording change has altered the re quirements for cabling attached to battery terminals It now states 10 8 3 Battery cables and other con ductors size 6 AWG 13 3 mm and larger shall not be connected to the battery with wing nuts 10 8 4 Multiple conductors connected to a battery shall be installed with the highest ampacity conductor ter minal closest to the battery followed by successively smaller ampacity conductor terminals 10 8 4 1 A maximum of four conductor terminals shall be per mitted to be installed on a single battery stud 10 8 5 Flat washers if used shall only be installed immedi ately under the split lock washer and nut of the at tachment stud This whole matter of the wing nut attachment has been a bit contentious for years These wing nuts do have a tendency to loosen and this will cause the terminal connector to heat up ex cessively due to the inherent resistance that is cre ated This represents a fire hazard on board Battery cables are the extremely heavy wires that connect your batteries to each other and to your dis tribution panel and starter motor They might also be used to connect other high amperage equipment Batteries and Battery Systems such as generators anchor winches and large invert ers The battery cables are by far the largest wires you ll find in your boat They are also among the most important and the m
34. Current and AC Equipment What Is Alternating Current Throughout this book on electrical systems for powerboats I have been talking about direct current electricity simply because more than 90 per cent of all systems on most boats use DC power Of course most of us already know what alternating current is but let s run through it one more time for review Most technically aware boatowners know that AC is the stuff that can kill you and that DC electrons flow in one direction whereas AC electrons reverse direction I will discuss AC dangers and safety later on but let s first take a closer look at the second item this apparent difficulty that AC electrons have in making up their minds which way to go In chapter 5 I discussed the manner in which direct current electrons flow through a circuit from the negative pole of a battery the cathode to the positive pole the anode With alternating current of course the anode and the cathode repeatedly and rapidly reverse positions Instead of flowing in a continuous stream from one end of the circuit to the other the electrons in an AC circuit travel only a short distance before changing their minds and rushing back to where they started They do this over and over again and while the electrons in an AC circuit get nowhere the power they generate has some important qualities that makes it better than DC for certain chores Before I go any further let s get some more basic terminol
35. Fig 3 19 Open circuit and no continuity Fig 3 20 Continuity and possible short circuit developments in this area utilize software and PC up loads from some of the newest high end meters for tracking voltage amperage and resistance changes over time Rest assured I ll be adding this capability to my arsenal of electrical test equipment in the not too distant future Chapter 4 Wire and Circuit Protection Standards and Repair Procedures Order Out of Chaos If you were to study the development of the Ameri can pleasure boating industry from the turn of the twentieth century to the early 1970s you would no tice a curious phenomenon While other developing industries gradually evolved a more or less uniform set of standards that dictated the minimum safety and performance parameters for their products the recreational marine industry had none For many industries such as automobiles aircraft food and health the government dictated the standards In other less critical industries and particularly in recreational industries the standards were imposed by the industry itself or by the marketplace Take golf for example which overlooking the differences in accident rates is remarkably similar demographically and statistically to pleasure boat ing Golfing gradually developed a set of rules and standards for course construction and equipment design that industries involved in the sport violated at their peril
36. GND terminal on the gauge These will almost universally have black insulated wire connected to them Engine Instrumentation Problems and Solutions Fig 10 3 Verifying instrument ground continuity at the tachometer As with all boat circuits the power feed is only as good as the ground return Here I m checking for a good ground for the instrument My meter leads are connected to the GND terminal on the tachometer and to a common ground stud on the back of an adjacent instrument Since we re checking for continuity it re ally doesn t matter which lead goes where Fig 10 4 Tachometer calibration The circular scale on the back of the tachometer shown here is used to select the appropriate calibration for your engine This is most often done with a mini slotted screwdriver and turning the setting screw inside the instrument to the appropriate point on the dial If you find continuity in the ground wire good ground for the gauge exists and the powering cir cuitry for the instrument is in good order Next use your engine wiring diagram to determine where the tachometer gray wire connects to your ignition system With the ignition key off determine if you have continuity between the connection point on the back of the tachometer and the point on the engine where it terminates usually at the ignition module If continuity exists here and the power and ground circuits are functioning normally the only r
37. Green A 4m Black GFCI OUTLET STANDARD OUTLET Fig 11 8 A GFCI outlet with a non GFCI outlet wired in to share protection To test a GFCL simply depress the test button on the assembly faceplate This trips the internal breaker and actually exercises the outlet s inner workings to ensure that it s functioning as it should If the test and reset buttons feel spongy and seem to have lost their crisp snap action odds are good that the GFCI mech anism is corroded and the outlet should be replaced Another point worth mentioning here is that just because the dock box that your boat is connected to at the marina is protected by GFCI and it always should be you shouldn t think that you re protected from shock hazard on your boat These dockside GFCIs are likely to be forgotten by the maintenance crew and never tested until it s too late To be safe always test the dockside outlets before you plug in your shore power cord and to eliminate any worry upgrade your boat with this important protection as soon as you can Checking Voltage Continuity and Polarity on AC Circuits Sooner or later problems will crop up with the AC circuits on your boat and you ll need to do basic multimeter tests for voltage polarity and continuity There is no need to be afraid of doing these tests on AC circuits even for the novice but following some basic rules in addition to the safety rules listed above will e
38. Monel stainless steel and bronze gang plug Plug assembly used for connecting mul tiple conductors gapping Adjusting the air gap between two elec trodes gel cell battery Type of battery with the active electrolyte contained in a gelatinous medium generator Generally a machine that produces electricity GPS Global positioning system ground At the potential of the Earth s surface A surface or mass at the electrical potential of the Earth s surface established at this potential by an electrically conducting connection either in tentional or accidental with the Earth including any metal area that forms part of the wetted sur face of the boat s hull 195 196 GLOSSARY ground fault circuit interrupter GFCI A device intended to protect people that functions to de energize a circuit or a portion of a circuit when a current to ground exceeds a predetermined value 5 milliamps in the U S harness A group of conductors running together heat shrink tubing Insulating sheath that shrinks to size when heated heat sink A mounting for an electronic compo nent designed to dissipate heat generated by the component to the surrounding air Hertz Hz The unit of frequency of an alternating current One Hertz is equivalent to one cycle per second horsepower A measure of power One horsepower is equivalent to 746 watts hot Generally considered the power feed conduc tor in electrical circuitry h
39. SYSTEMS explode just like so many kernels of popcorn in a hot pan Exactly the same thing happens when the battery cables are accidentally reversed If you aren t planning on serving fried diodes for lunch be very careful when connecting or disconnecting your battery cables Three Step Voltage Test Now you re ready to hook up your multimeter and do the three step voltage test This simple test is ef fective on systems that have built in voltage regula tors not serviceable by the owner Turn off all the accessories on your boat set your multimeter to read voltage and connect the probes across the battery terminals red to positive first and black to negative Make sure the battery master switch is turned to the battery on which you re work ing Read and record the battery voltage It should be around 12 5 volts if you adequately discharged the battery from full charge This reading is called the ref erence voltage write it down somewhere handy Next start your engine and run it up to a nor mal mid range operating rpm with all accessories turned off Take and record your voltage at the bat tery This is the no load voltage and it should be no more than 2 to 2 5 volts higher than the refer ence voltage Write down the no load voltage next to the reference voltage With the engine running at the same rpm you used to check the no load voltage turn on all your DC electrical accessories Read your voltage at the battery This
40. The rules for routing wires are simple and com mon sense will go a long way toward keeping things right gt Harnesses unless they run through a conduit or built in channel need to be supported at least every 18 inches 45 7 cm gt AC and DC conductors should never be bundled together unless separated by sheathing gt Grommets must be used when running wires through cutouts in bulkheads and fiberglass pan els Some acceptable types are illustrated in figure 4 20 pm Wires must be kept as high above the bilge as pos Fig 4 18 Battery supply circuits with no battery master switch installed ABYC sible and those wires that must live there such as the bilge pump wiring should have waterproof Wire and Circuit Protection Standards and Repair Procedures PVC Pipe Grommet Silicone Adhesive Fig 4 20 Acceptable methods of providing abrasion protection through bulkheads connections Sealing heat shrink tubing works well in these cases See the circuit repair section of this chapter All wiring should be routed at least 2 inches 50 8 mm from wet exhaust system com ponents and 9 inches 22 9 cm from dry exhaust components Methods of securing wire can be as simple as us ing nylon wire ties with screw holes for attachment The recommended method of securing wires run ning above or near moving machinery is to use the plastic dipped or rubber insulated metal fasteners commonly fo
41. This variation in exact speed specifications is one of sev eral reasons that if module replacement is ever needed the exact module for your engine as de termined by the serial number of the engine must be used Don t be fooled into thinking that a module that looks just like yours is the correct one for your en gine the internal calibration of the look alike could be very different from yours Acceleration Spark Advance Allignition systems need some sort ofacceleration spark advance mechanism Older systems with breaker points used a mechanical advance with centrifugal weights at tached to the plate inside the distributor to which the points were attached As engine rpm increased it gener ated centrifugal force and the weights moved the ignition points relative to the center shaft within the distributor This changed the place where the points opened and closed and adjusted the timing of the spark On newer engines with electronic ignition timing is controlled by the ignition control module or on the latest computer ized engines by the onboard microprocessor This change in timing allows more time for the fuel air mixture to completely burn as engine speed increases The faster the engine turns the more time is required for combustion and the more the timing must be advanced When the engine is accelerating the ignition control module may add more spark ad vance to the base timing the starting point for timing on all
42. Try the sounder for a few days under all of the conditions you re likely to encounter If the display picture is clear and accurate go for it If not perfect but still functional try different locations inside the hull Avoid areas of the hull where it inclines more than about 15 degrees Mounting the transducer at any an gle greater than this will send its wave pattern to the side of the boat and not straight down to the bottom Once you find the best spot for the transducer clean away the temporary adhesive and degrease the 3M Brand 4200 Adhesive i Fig 12 10 Inside the hull mount with transducer glued in place hull with some acetone or alcohol Lightly sand both the face of the transducer and the hull with some medium grit 100 grit sandpaper Wipe down everything once more to clear the dust away Next apply enough fast curing 3M 4200 poly urethane adhesive to provide full contact with the entire face of the transducer Push the transducer into the adhesive and wiggle it slightly from side to side to break any air bubbles in the glue Allow it to sit for about two hours to cure 3M 4200 is much better for this purpose than the 3M 5200 it cures much more quickly than the 5200 and is a bit less tenacious making for easier replacement of the transducer when the time comes to do so Figure 12 10 illustrates a typical glued in transducer Through Hull Mount Through hull mounting of a transducer gives exc
43. Voltage drop as we discovered in chapter 1 is the natural and unavoidable loss in voltage as amperage works to overcome resistance in a circuit The drop is the amount of source voltage loss caused by the in herent resistance to electrical flow through the wiring in the circuit and any connections where wires and circuit components are installed 31 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Virtually all circuits contain some resistance Thus there is always some voltage drop in every cir cuit This is true in AC circuits as well as in DC cir cuits However because of the trade off between voltage and amperage as voltage in a circuit goes up the amperage required to do the same amount of work goes down the drop in a 120 volt AC circuit is of little consequence With low voltage DC cir cuits however voltage drop is a major concern and you ll need to know how to measure it So how much voltage drop is acceptable Once again our friends at the ABYC offer some guidelines Section E 11 of the Standards and Technical Infor mation Reports talks about critical and noncritical circuits Certain fixtures such as navigation lights bilge pumps and navigation equipment are required for safety and their efficient operation is critical However the brightness of a cabin light or the speed of a fan in the galley just isn t that important Thus the standards allow only a 3 percent maximum volt age drop for critical equipment an
44. a better choice This is a point worth checking before spending several hundred dollars on a clamp type meter if you ll be working with many circuits with less than 1 amp of current How ever most onboard electrical equipment will use 1 amp or more The most common exceptions are electronic equipment in standby mode and some small fluorescent lights generators and inverters to make sure they are run ning properly The Ancor meter does not have a diode test function and in actual use I have found that it will not effectively test some diodes commonly used in 29 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS ACIDC CLAMP METER ONE TOUCH ZERO ene BAS d Fig 3 2 Ancor Prova clamp type meter This unit retails for around 300 and offers amperage reading capability up to 200 amps and a frequency checking function useful for some AC tests Made by Prova marketed in the United States by Ancor marine applications such as those used in battery isolators It does work for testing most alternators but it may not be adequate for many inboard or in board outboard starter current tests The Ancor part number 702070 is available through major marine retailers such as Defender Industries and West Marine for about 300 Fluke Model 336 If you re the type that simply has to have the best Fluke Corporation makes what I consider to be some of the finest multimeters available anywhere There are
45. and 10 10b show how far we have come since the first edition of this book New boats today will likely be equipped with a networked system for dis tributing engine data among other things The Mer cury Marine SmartCraft display in figure 10 10a is an integrated part of that system and effectively replaces the traditional gauges discussed in this chapter The data come from an engine mounted computer like the one shown in figure 10 10b All wiring is done through proprietary harnesses with multiple pin plug assem blies as in figure 10 10b Troubleshooting instrumen tation problems on these systems is a bit more Fig 10 10a SmartCraft display Engine Instrumentation Problems and Solutions Fig 10 9 An oil pressure sending unit on a GM V8 engine On this engine it s located next to the ignition distributor complicated than some of the procedures described for conventional instruments But with an ohmmeter you can check continuity of the pin connections from one end of the harness to the other and at least determine if there is a problem with the harness or a plug assem bly Beyond that there is not much you can do with out specialized equipment that goes beyond the scope of this book One resource for those that want to learn more about these systems is my latest book Advanced Marine Electrics and Electronics Troubleshooting rd i A Fig 10 10b Engine mounted computer Chapter 11 Alternating
46. and in the case of AC panels a reverse polarity indicator parallel circuit A circuit that allows more than one path for current to flow pie formula PXI E orW VXA pinging Knocking noise from engine that sounds like marbles are bouncing inside polarity The distinction between and in a circuit or on a load device potential See electrical potential power The rate at which energy is used or con verted The unit of measurement is the watt which equals amperage times the voltage One horsepower equals 746 watts See also horsepower pulsarcoils See trigger coils radome See scanner reference voltage power source The open circuit voltage of a relay An electromechanical switch See also sole noid reserve capacity The time in minutes that a battery can deliver 25 amps before dying resistance Measured in ohms The opposition to electrical current flow amps reverse polarity Connecting battery cables back wards Or in AC the reversal of the black and white conductors RFI Radio frequency interference emitted by elec trical devices Can produce radio noise and can cause navigation equipment to malfunction ripple voltage Small amount of AC voltage that typically leaks past rectifiers inside alternators 197 198 GLOSSARY root mean square RMS multimeter One using peak AC voltage values to calculate its readings rotor The moving component inside an alternator that has the fiel
47. another 10 amp fuse We aren t quite done yet though Some mo tors and inverters require what is called a slow blow fuse Motors and certain other devices require as much as five or six times more amperage to get started as they will use when they are up and running Inverters that supply AC loads to motorized equipment like electric drills will experience a surge of current when ever the AC motor starts up because AC output is proportional to DC input Obviously if you tried to protect any of these circuits with a regular AGC fuse you would stay pretty busy changing fuses A slow blow MDL fuse allows a substantial amount of ex tra current to flow for a specified length of time before it blows and opens the circuit and is just the thing for this situation Never make assumptions about the amperage of an AGC or MDL fuse based on a visual inspection of the element Manufacturers use different materi als for these elements with varying sizes and current handling capabilities Two fuses with elements that appear to be the same size could have entirely differ ent ratings You need to read the amperage specifi cation embossed into the end caps of the fuse itself to be sure ATO Fuses An increasingly popular fuse being used by many of the large production boatbuilders is the ATO type commonly referred to as a blade type fuse ATO fuses work in exactly the same way as the barrel type AGC fuses mentioned above the heat from exce
48. any event you should spend some time reviewing your engine workshop manual getting familiar with the cooling system and troubleshooting procedures before prob lems develop Carry spare water pump impellers and fan belts at all times Low Voltage Reading If your volt gauge suddenly shows a lower than normal or a higher than normal voltage reading you can easily verify the accuracy of the gauge by doing an open circuit voltage test at your battery Use your multimeter and take the reading with the engine running as outlined in chapter 5 Low or High RPM Irregular engine rpm usually shows up as an erratic reading or no reading at all on the tachometer If the engine is running normally in spite of the erratic reading get the boat back to shore and follow the electrical troubleshooting steps outlined in the next section of this chapter Trim Gauge Prohlems Of all the instruments on a boat with an inboard outboard engine the trim gauge is the one with the highest failure rate This is because the sending units on these boats are often located underwater on the side of the engine drive unit Here they are exposed to the worst environment any electrical equipment can experience Engine Instrumentation Problems and Solutions Faulty trim gauge readings always indicate an electrical malfunction and have nothing to do with the function of the drive itself To be safe take a look over the transom just to be sure the drive is down
49. are all different so work from your engine s manual and if you re uncertain of the procedure consult your local dealer Regulated Outboard Systems Larger outboard engines and on the newest units even the smaller ones have voltage regulators in stalled into the circuitry Sometimes these are com bination regulator rectifiers like you might find on an inboard system If a component is going to fail in the system it will most likely be this regulator rectifier The three step voltage test described on pages 92 93 will work on these systems just like on inboard systems It s best to use your engine manual for the tests necessary to isolate charging system problems in the regulator Shore Power Battery Charging Systems and Installations Permanently installed battery chargers connected to your boat s shore power system fall into one of two general categories The most common is the ferro resonant constant output charger The other is known generically as a smart charger or three step charger Many of the smart chargers available today also have a fourth stage known as an equalization stage and are thus four step chargers More on that later A third popular type of battery charger is really a combined device known as an inverter charger that not only con verts 12 volt direct current into 120 volt alternating current but also incorporates a quality multistage battery charger into one handy and compact unit As you ll see in t
50. be testing directly across switches and relays or from one end of a wire to the other even though I said earlier that you shouldn t do this Figures 3 9 3 10 3 11 and 3 12 illustrate the various meter connection possibilities for this test Begin with the circuit you re measuring turned off The meter should be turned on set to measure DC voltage and if your meter is not self scaling it should be set to the lowest voltage on the DC volts scale usually 2 volts Once the meter is connected turn the circuit on and take a reading on your me ter The reading is the voltage drop at that point in the circuit Record the reading Measure the voltage drop at each wire and connection in the circuit including the negative return then add up the results The total of all these measurements must fall within either the 3 percent or 10 percent limit Any reading that s a lot higher than the others in the circuit indicates a point in the circuit with excessive resistance or voltage drop Correct any problem by cleaning or tightening the connection or by replacing the connecting wire Measuring Amperage As already discussed there are two methods used to test amperage One method uses meter leads and re quires the disconnection of the DC power lead for the circuit you re testing I discuss AC in more de tail in chapter 11 the other uses a clamp type in ductive meter Using Meter Leads Unlike voltage checks amperage checks with a
51. before moving breakers out of place Fig 4 12 Circuit breaker removed showing paper label Af ter a few years you can count on these labels being unread able and even coming unglued and disappearing altogether Wire and Circuit Protection Standards and Repair Procedures Fig 4 13 Ign protected label on a protected breaker This is the only breaker type that should be used in an engine room or compartment where CNG or LPG are stored of the ABYC standards There are exceptions to the rules for diesel fueled boats but on countless occasions I have seen jerricans of gasoline stored in diesel engine rooms This circumvents the in tent of the regulations and one foolish move by the owner of these boats could cause a disaster An improperly stored LPG liquid propane gas tank is also a time bomb Testing Fuses and Circuit Breakers One of the very first things you should check when a circuit of any type becomes inoperative is the condi tion of the fuses and circuit breakers so it s impor tant that you know how to verify that they are working properly You might be saying to yourself Hey my boat has all glass bus type fuses All I need to do is look at a fuse and I can tell if it s blown or not This is not necessarily true Often these AGC fuses will fail under the end caps where the break in the element is out of sight When some brands of cir cuit breakers trip the reset lever remains in t
52. before starting the engine On inboard engines hydraulic trim tabs oper ated by an electric servomotor control trim They have a comparatively low failure rate because all the electrical components are located inside the hull and are not exposed to seawater Fuel Gauge Problems Common sense should assist you with any erratic reading on your fuel gauges As soon as you buy a new boat you should establish an approximate fuel consumption rate Calculate the gallons of fuel used by your engine per hour of running time at different rpms Based on that usage and the capacity of your fuel tank you should be able to estimate the amount of fuel in your tank and use that estimate to judge the accuracy of your fuel gauge For example if you burn 10 gallons per hour at 3 000 rpm and have a 50 gallon fuel tank you can safely operate your boat for four hours and still have an emergency reserve no matter what your fuel gauge tries to tell you Problems with fuel gauges like problems with trim gauges are almost always the fault of the tank sending unit The test procedure for this will be found later in this chapter General Instrument Troubleshooting The pros say that whenever an instrument problem crops up you should always verify that a problem does in fact exist by swapping the engine gauge with a quality shop gauge which is often a mechanical gauge This is good advice but unless you have a personal friend who s a mechanic which i
53. circuit they serve while most appliances that share a circuit are wired in parallel Figure 1 5 illustrates this arrangement The important thing to remember here is that the voltage available to the loads wired in the par voltage as all the others This arrangement has three obvious advantages first it allows all the appliances on the circuit to share a single pair of leads from the bat tery and a single fuse or cir cuit breaker second each load or appliance will have direct access to battery volt age so that it can do its job with peak efficiency and Circuit Protector 9 Switch On Cabin Light Cabin Light Cabin Light Battery third if one appliance on the circuit should fail in an open condition electro Fig 1 4 A typical parallel circuit In a parallel circuit there is more than one path for electrical current flow Electrical Basics You Need to Know allel section of the cir cuit will be quite close to the voltage at the begin ning of the circuit It s not too hard to see that by using series parallel circuits manufacturers can save a lot of money on switches wire and circuit protectors but series parallel circuits also greatly simplify a boat s overall electrical system with no sacrifice in performance or safety Circuit Protector Battery Q Switch On Cabin Light Cabin Light Cabin Light Ohm s Law and What It Can Tell Us Georg Simon
54. coil is really a step up transformer The primary side of the coil has a series of wind ings that conduct battery voltage The magnetic field Maintaining Marine Ignition Systems that s created around the primary coil engulfs sec ondary windings inside your coil Because there are a great many more windings in the secondary side of the coil than there are in the primary side the voltage that s induced by the magnetic field is stepped up to the high level needed by the spark plugs By altering the number and ratio of windings in the primary and secondary sides of the coil engineers determine the exact voltage we will get from the secondary side of the coil Distributor When the very high secondary voltage leaves the coil it goes to the distributor where it s directed by the ro tor inside to the correct cylinder at exactly the right moment to fire each spark plug The rotor rotates inside the distributor cap and directs secondary volt age into the correct ignition wire and ultimately to High Secondary Voltage 4 Distributor Primary Terminal Terminal Primary Winding Electromagnetic Field Distributor Distributor Fig 7 1a Current flow through a typical electronic ignition system In this diagram the thicker lines indicate secondary high voltage conductors Primary voltage is equivalent to battery voltage and is indicated by the arrows which also show the direction of flow at the
55. common con ductors are made of copper Aluminum is used in some automotive applications but aluminum con ductors of any type including terminal strips and studs are strictly prohibited in the ABYC electrical standards The soft aluminum used in wiring cor rodes easily unlike the hard aluminum used in boat hulls and it can become brittle and break when sub jected to the constant vibration and flexing of a typi cal boat underway It also isn t as good a conductor as copper and the added resistance means that it gets hotter quicker than copper Don t ever use alu minum wire on your boat and if you find any al ready installed immediately remove it and replace it with copper wire In addition solid wire especially the solid copper Romex that s used in house wiring is never accept able on boats This precludes the use of many wiring types found in hardware stores or in home supply houses Solid copper residential wiring breaks easily under vibration and it was never intended to with stand the exposure to moisture or oil and gas fumes found on today s boats According to the ABYC specifications the only acceptable material that may be used for boat wiring is stranded copper Although not specifically men tioned in the standards good quality boat cable to day is often tinned as well This means that every strand of copper in the wire is coated with a thin layer oftin solder actually that impedes the formation of corrosio
56. current This is to maintain any internal memory the equipment may have for such things as preselected radio stations So when selecting your power for the memory function on your player if needed check Installing Your Own DC Accessories Fig 9 9 Typical bullet type electrical connectors These are useful if installed as opposites on the positive and nega tive return wires in preventing a reverse polarity situation that can damage sensitive electronic equipment your owner s manual remember that this connection must be live at all times and probably the best source of power will be at the feed side of your main battery switch or at the battery itself Adding Speakers When it s time to connect the speakers for your newly installed CD player regular speaker wire available from Radio Shack and other stereo supply houses will do the job However because of the bet ter insulation a better choice would be the marine grade duplex wire already mentioned The ABYC doesn t address speaker wires in its color coding scheme so select duplex wires with dif ferent color schemes to help identify left and right speaker leads When running these leads remember to observe polarity and don t mix up the wires As with any wiring on board speaker wires should be supported at least every 18 inches Once wire gauge and circuit protection decisions have been made the six step list that follows will guide you through the inst
57. devices One thing that will make a minor difference in the installation of your GPS unit is whether or not you select a standard or differential GPS DGPS configuration Like all of the equipment discussed so far the lo cation for the display unit must be carefully consid ground just as you would for any electrical appliance Use your multimeter set up to read volts to make sure the voltage is not below your unit s mini Word uad a mum threshold If it is deter ground mine why by using all of the methods described throughout this book Checking your transducer may require hauling the boat so you can get at the face of the unit If you re up to it a brief underwater swim may be all GPS Antenna Calibrated Factory Supplied Cable that s needed With the sounder turned on you should hear a ticking noise coming from the Fig 12 13 Wiring layout for a standard GPS installation transducer as it attempts to transmit its signal If you don t hear a ticking sound the trans ducer is faulty Also if you rub the palm of your hand across the face of the transducer while someone watches the display they should get a fuzzy reading across the screen If not the transducer is at fault and needs to be replaced Naturally you should also become familiar with the controls and calibra tion settings for your fish finder and depth sounder and be sure May have a chassis ground GP
58. diagram just as you find it Don t forget to write down the color of the wire the gauge if you can tell what it is sometimes the gauge is written on the wire more on this later and the circuit ID number or code if your boat has one Trace each wire for its entire length and when you come to a switch fuse circuit breaker or any other device that you may or may not be able to identify draw that in too When you encounter wires that leave this particular subsystem and go to another such as the ones connected to the accessory position on your starter switch show them going off the page and label their destination to radio to alarm system or whatever is appropriate If you can t tell where one of these wires goes just label it with a question mark for now You may not believe this but you now have a rough draft of your wiring diagram for your starter and charging subsystem Once you redraw it it should look something like the one in figure 2 2 If it still doesn t look like much don t worry as long as you can look at the drawing and relate all your little sketches and sym bols to actual components on your boat Now that you understand how the process works you can work your way through each of the subsys tems on your boat If you have a large or an unusu ally complex boat this will take a lot of time but keep at it Eventually you ll have a complete albeit crude drawing of each of your subsystems Go t
59. engines The amount of spark advance added depends on how fast engine rpm increases Rapid throttle changes induce rapid timing changes Beyond the Basics Outboard and PWC Ignition Systems On outboard and personal watercraft PWC ignition systems some of the parts are located under the en gine flywheel So if your diagnosis leads you here you may need the services of a professional mechanic who has the tools needed to get at these parts All manu facturers include test procedures in their workshop manuals that use special test equipment such as Stevens or Merc o tronic ignition system testers This equipment is too expensive to be a part of your tool kit Unless you do this sort of work daily it just isn t practical to have this stuff This section will show you how to narrow down the most common ignition problems using simple tools and your multimeter Capacitive Discharge Ignition System If your engine was built after 1975 it most likely has some variation of a capacitive discharge ignition CDI system which works by charging a capacitor and releasing this charge to the appropriate igni tion coil at just the right time We have already taken a brief look at thisin the overview of how out board and PWC ignition systems work earlier in this chapter Different engine makers use different names to describe the parts they use in their CDI systems but they all are similar Magnets carefully positioned on the engine s fly
60. for a given application such as a deep cycle battery where a cranking battery is needed and vice versa and using batteries that are too small for the task at hand The information on selecting bat teries at the beginning of this chapter should have corrected any problems you may have had in those areas And then there are the boatowners who chuck out perfectly good batteries they have convinced themselves are bad I ve seen more batteries unnecessarily replaced than any other systems component I can think of It seems that many otherwise sane people blame the bat tery for everything from an autopilot that doesn t work properly to warm beer They will throw away a healthy battery without a thought to the more probable causes of their troubles Just because your engine is cranking over slowly or your cabin lights are getting dim doesn t mean you need a new battery With the retail price ofa small marine battery bouncing around 100 I think it s worth checking the old one to make sure if you re ally need to replace it before you discard it As battery technology and construction meth ods have improved over the years maintenance has gotten a lot easier The biggest problems we used to have were keeping the terminals clean and topping up the cells with distilled water These tasks are still necessary with the new versions of wet cell batteries but the new technologies have greatly reduced the constant need to add water Battery case co
61. for voltage drop 43 44 45 connection repairs 59 64 connectors 60 61 bullet type 145 butt 63 64 coaxial cable 185 86 continuity 37 alarm on multimeters 27 checking 132 33 150 51 169 70 measuring 37 39 trigger coil and short to ground tests 117 INDEX corrosion of battery terminals 75 of cables and connections 20 75 of fuses 142 galvanic 177 protection for ignition sys tems 104 106 silicone sealers and 109 stray current 177 78 cranking batteries 69 70 82 crimping 61 63 crimping tools 11 61 62 63 cross induction 161 62 188 cruisers batteries for 70 72 current draw test 127 28 current requirements for starter motors 127 DC to AC inverters See invert ers decibels dB 184 185 deep cycle batteries 67 68 69 70 82 depth finders installing 186 90 187 188 189 troubleshooting 189 90 de rating 160 detonation See pinging Deutsch plugs 104 106 diesel engines amperage requirements 71 72 current draw test 127 engine shutoff 85 oil pressure sender failures 152 tachometer for 150 differential GPS DGPS 190 91 digital multimeters 26 28 38 diode rectifiers 95 96 diodes 27 79 80 82 86 99 direct current DC galvanic isolators and 178 inverter chargers and 96 rectifiers and 86 87 95 96 direct current DC accessories amperage requirements 136 color coding 138 fuses and circuit breakers 137 38 installing 136 46 length of wi
62. found that the best solution to this dilemma of which multimeter to buy is to combine several rela tively inexpensive instruments rather than to buy one meter that does everything A basic digital multime ter with a 10 or 20 amp capability will be just fine for testing most of the lighting and small motor cir cuits on your boat For measuring any circuits draw ing over 20 amps Snap On makes an inexpensive pair of inductive pickup analog amp gauges Snap On part number MT1009 which read to 100 amps in DC and to 500 amps in AC In this case the ana log scale is fine because with high amperage tests we don t need to measure tiny fractions of an amp a reading in whole amps is plenty These gauges will serve your needs well for everything but shore power or AC generator work Figure 3 1 shows one of my inexpensive 20 amp multimeters and the MT1009 Snap On gauge set This combination of instruments can be bought for under 100 and will measure current up to 500 amps Fig 3 1 A 20 amp multimeter with Snap On inductive me ter set offers a fairly economical solution for measuring am perage up to 500 amps The combination can be purchased for under 100 The ideal situation for general marine work would be two meters in your toolbox one medium priced general purpose meter with a diode check feature and a 10 to 20 amp capacity and one inductive pickup meter with at least a 600 amp capacity Most working marine electricians have
63. gt Waveform Most working electricians will have access to an oscilloscope a testing device that shows the track of an electrical impulse as it re verses direction through a single cycle in an AC circuit The resulting sinusoidal wave shows the variation in voltage from zero up through the peak at about plus 170 volts then back to zero then down to a minus 170 volts then back to zero This fluctuation averages out to 120 volts and is why I suggested earlier that if you intend to work with AC electricity even a little you should invest in a true RMS root mean square multimeter The cheaper meters average responding type read the peak voltages without consideration of the time the circuit is at zero voltage and are only effec tive for measuring true sinusoidal AC wave forms When working on boats waveform is most im portant when considering inverters No you don t have to run out and buy an expensive oscilloscope Just knowing what a waveform is and why it s im portant is plenty for now AC on Your Boat Just a few years ago any use of alternating current on board any small boat under 35 feet or so was extremely unusual Some of the fancier boats did have a dedicated battery charger Constavolt was a popular one but the best of these were expensive and inefficient and the good ones weighed nearly 100 pounds My how times have changed Today it Alternating Current and AC Equipment seems that even the smallest of boat
64. idea of installing a low cost automotive starter motor in place of a proper marine one it could be deadly Copyright 2000 2007 by Edwin R Sherman Click here for terms of use 124 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Starter Motor Problems and Solutions Because engine makers all use similar engine blocks and parts starter motor circuits have many similar ities from one brand of engine to another There fore I have been able to develop a generic procedure for troubleshooting and repairing them However the specifics for your boat s engine can only be found in your workshop manual Use the procedures in this chapter as a detailed guide to get you started in the right direction for locating and correcting specific problems I will try to direct you to sections of your workshop manual when they are needed The illus trations that follow show the major parts of the most common starter motor circuits Figure 8 1 shows a typical OMC Volvo Penta starter circuit with all the important parts mentioned in the list that follows Figure 8 2 on page 125 shows a typical MerCruiser starter circuit Basic Diagnostics There are five basic symptoms of starter motor and starter circuit problems and basic diagnostics Let s look at the symptoms first and we ll explore each in detail in the next sections gt The starter motor is lethargic and turns the en gine slowly First check the condition of the bat tery and cable c
65. ignition system can be broken down into six general categories listed below You should attack the ignition system only after you re certain that the fuel system and your engine s compression are up to snuff the procedures for do ing those things are not covered in this book but are mentioned in your service manual If you don t have some experience in mechanics you should get pro fessional help rather than troubleshoot on your own You ll need to carefully follow the procedures found in your engine s workshop manual for some of the items listed here Engine runs sluggishly and overheats Check the ignition timing and spark advance system Engine pings Check the ignition timing and spark advance Make sure the spark plugs are ofthe recommended type Engine is hard to start Check for spark at the plugs and the spark plugs themselves Check the ig nition bypass circuit the battery and associated wiring and the distributor cap Figures 7 12 and 7 13 on page 113 show my favorite spark tester in use but more on that later pm Engine misfires Check the spark plugs and leads rotor and distributor cap and ignition coil for loose connections at the coil and ignition switch Also check the engine firing order plug wire rout ing and the engine timing Engine fires when cranked but stops when key is released Check the ignition switch and related wiring gt Engine cranks but doesn t start Check for spark at the
66. is always slightly larger in diameter than the negative Don t believe the cable colors Lots of people replace cables with whatever color cable is available at the time they needed a new one Be absolutely certain you know which is the positive and which is the ground negative cable Remember battery electrolyte is sulfuric acid It will burn through shirts pants shoes wood most metals and your skin Anything exposed to battery electrolyte should be thoroughly flushed and imme diately rinsed in fresh water Even then your favorite jeans or T shirt will probably end up with a souvenir set of holes after the first wash Battery Location A major part of battery safety is directly related to the way batteries are installed in your boat Our friends at the ABYC have addressed this issue in section E 10 of the Recommended Standards They list three acceptable possibilities for battery installation 73 74 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS 1 Covering the positive battery terminal with a boot or nonconductive shield Installing the battery in a covered battery box Installing the battery in a compartment spe cially designed only for the battery or batteries In addition there are a few other rules in the standards with which you should be familiar gt The battery should not be located near fuel system components such as lines filter canisters or tanks gt Battery box covers must be ventilated and
67. is called the open circuit voltage test If you don t have a built in meter you can use your multimeter and take a reading right at the battery terminals Figure 5 17 shows the voltmeter connected to a battery for an open circuit voltage test Be sure all ac cessories are turned off when performing this test otherwise you ll get a low reading There is a direct relationship between specific gravity and a battery s open circuit voltage You need a digital voltmeter for this test as the accuracy Battery Fig 5 17 Voltmeter connected for an open circuit voltage test This test will give you an indication of the battery s state of charge but can t tell you which cell within the battery is the culprit required is difficult to read on an analog unit As with the hydrometer test the battery must be stable A heavy load or a recharge just before doing this test will give you a totally inaccurate reading Let the battery sit for an hour or so before the test and your multi meter will give you a meaningful reading Use a digi tal voltmeter hooked up as shown in figure 5 17 and compare the reading to the table at right this will give you a good indication of your battery s state of charge Load Test The load test tells you whether the battery has enough amperage to back up the open circuit voltage Open Circuit Voltage versus State of Charge Specific Gravity Open Circuit State of Specific Voltage
68. is required on self limiting alternators This applies to most alternators with internal voltage regula circuit protection requirements and as already stated these are the only circuits on board that are exempted If a wire is connected directly to a battery terminal and is contained throughout its entire length in a sheath or enclosure such as a conduit junction box control box or enclosed panel the fuse or circuit breaker should be placed as close as practi cal to the battery but no farther than 72 inches 1 83 m away A common question that arises over this exception is just what constitutes a sheath The black corrugated plastic tubing used by most production boatbuilders fills the bill for sheathing and is a good inexpensive choice A wire not connected directly to the battery termi nal can be protected with a fuse or a circuit breaker mounted as far as 40 inches 1 02 m from the point of connection as long as the wire is contained in a sheath For example a large stud on the starter motor solenoid is commonly used to con nect various components on the engine Wires so connected can have fuses or circuit breakers lo cated as far away as 40 inches from the stud as long as the wire is in a sheath hence the 7 40 72 rule Battery chargers covered in chapter 6 add a de gree of complexity to the basic rule Built in battery chargers engine driven alternators and even solar panels are all considered battery ch
69. is the loaded voltage and it should be at least 0 5 volt above the reference voltage Write it down with the others If the no load voltage is no more than 2 5 volts higher than the reference voltage and the loaded volt age is at least 0 5 volt more than the reference voltage your alternator and regulator are operating correctly If the no load voltage is above the 2 to 2 5 volt limit the battery is being overcharged and the voltage regulator is either defective or has a poor ground On alternators with internal regulators remove the alter nator and get it overhauled If your engine has an ex ternal regulator use your ohmmeter to check for continuity between the regulator s ground terminal marked GND and a good ground on your engine If the voltage readings are below the limits de scribed here you ll need to make one more check to ensure that the alternator is getting field current when the boat s ignition key is turned on Use the diagrams in figure 6 1 on page 88 to identify the ter minal on the back of the alternator marked by either an F EXC or IGN This terminal which is supplied ignition voltage hence the possible IGN marking is where the excitation supply of voltage is sent through to the field F windings wound around the alternator s rotor With your boat s ignition key turned on there should be a voltage reading very close to the reference voltage at this terminal If not use your workshop man ual
70. keeping your wires where you want them Fig 9 3 Heat shrink type crimp connectors These are ex pensive but worth every penny if you can get your hands on them 141 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Dedicated Bilge Pump Switch Panels Now that you ve got some of the basic supplies assembled decide if you want to tie this new cir cuit into the distribution panel or connect it di rectly to one of your batteries with an optional dedicated bilge pump switch panel as shown in fig ure 9 4 These switch panels offer an integral fuse and a choice of manual or automatic operation The better units as shown also have a pilot light that lights up when the circuit is on Be careful here though I have found many of these switch panels with 10 amp fuses installed in the holder If you have one of the smaller pumps this is a problem they often require as little as a 1 5 amp fuse A 10 amp fuse would never do for a pump with a locked rotor the fuse would surely allow the pump to burn up Always double check the fuse rating when in stalling one of these switch panels Although the bilge pump switch panel described above could be made from various off the shelf com ponents by a boatowner who had the inclination and time to do it these assemblies are so reasonably priced that I generally use the standard switch panel after making sure the fuse is adequate of course Fig 9 4 Bilge p
71. ll remember how they go when you re ready for your spring launch Remember that connecting 24 volts to a 12 volt system can be a very interesting but very expensive mistake The parallel hookup is not what you ll find on your boat as a bat Parallel Batteries Batteries Fig 5 8 Two 12 volt battery pairs one in series one in par allel Remember that series connections combine the voltages of the batteries connected parallel connections combine the available amperage but do not change the voltage tery switch will usually separate the batteries unless of course you re building a large battery bank from multiple batteries I am just trying to illustrate what happens to amperage and voltage in these circuits Battery System Components Besides the batteries other components found in any battery system are as follows Every system will have cabling connecting the batteries to each other and to the distribution panel and starter There will be a master control switch of some type to separate and isolate the individual batteries In some cases a diode type battery isolator is used to prevent batteries dis charging into each other And in some of the newer installations a device called a battery combiner will be used to do the same thing Naturally all of these cir cuit components must be rated for the amperage they are expected to carry Let s go through this list and take a look at each component Battery
72. loads such as several cabin lights or navi gation lights are served by one pair of wires and one main circuit protector Series Parallel Circuits Series parallel circuits are Cabin Light Fig 1 3 A series circuit with three electrical loads Note that with this circuit type there is only one path for electrical current flow There is still another fundamental flaw in any se ries circuit that s expected to carry more than a single load If any one of the electrical loads should fail in the open position that is break the circuit as when a light bulb or a fuse blows the flow of current through the circuit will cease shutting all the other appliances down as well Parallel Circuits Parallel circuits such as the one in figure 1 4 solve both problems we have with the series circuit by providing more than one path through which elec trons can flow which means that each load on the circuit receives the same nothing more than complex sometimes very complex combinations of series and parallel circuits In the real world of marine electrical systems most of the circuits found on our boats are actually series parallel circuits because they combine components wired in series like switches and fuses in the primary feed of the circuit and at some other point loads are wired in parallel Certain components such as switches and fuses of many actual circuits are usually wired in series regardless of the type of
73. of a dy namometer specially designed for outboard engines The average boatowner doesn t have these tools If you re well equipped and have a reasonable amount of engine experience you can set the timing by following the procedure outlined in the Engine Synchronization and Timing section of your work shop manual On smaller single carburetor engines the procedure is not especially complicated and by following the instructions carefully someone with limited experience can do it On the larger engines of over 25 horsepower do it yourself is not recom mended The variables here are many and go beyond the scope of this book To sum up timing and its importance in ignition system diagnosis remember these important facts Timing will rarely change unless someone alters the carburetor linkage or adjustments Or the flywheel comes loose from the crankshaft Or the fly wheel magnets become unattached from the under side of the flywheel a fairly common problem on some engines Or the engine has many hours on it and the timing plate under the flywheel is worn and has excessive play So if no one has tried to adjust your carburetors and your flywheel isn t loose it s highly unlikely that your ignition timing has changed But if you have any doubts based on all the information presented here get your timing professionally checked More on the CDI Unit If your engine has been intermittently quitting or in termittently losing rpm th
74. of engine run time Spark plugs last almost indefinitely with these systems but it s best to remove the plugs seasonally for inspec tion and to apply a light coat of antiseizing compound to the threads If you wait until the plugs actually wear out you may find that they ve rusted themselves in place making removal almost impossible Ignition Wires While the voltage coming from the secondary side of the coil is very high up to 50 000 volts the amperage is comparatively low This means that the wires that transmit this current from the center tower of the coil through the distributor and on to the spark plugs must be of a very high quality and contain a very low resistance Cheap or deteriorated ignition wires are one of the primary causes of ignition system failure They can also cause maddening radio interference and a host of problems with other sensitive electrical equipment not only on your boat but on the boat in the next slip as well It really pays to keep a sharp eye on your ignition wires When they start to look dete riorated they are deteriorated Replace them Spark Plugs The last and one of the most important parts of the ignition system is the spark plug It s the spark plugs that deliver the sparks to the cylinders and those sparks are the focus of the entire system Spark plugs come in a bewildering variety of types and sizes Fortunately your job as a boatowner is fairly sim ple The engine manufacturer will have
75. of fuss and time However that same electrician working on a 12 boat is quite likely to spend half or even more of his or her time just trying to figure out how the systems are wired Manufacturers and boatbuilders outdo themselves it seems in the creative way they locate components in obscure lockers and hide wiring in unlikely places To further complicate the situation many ma rine components such as radios radar and naviga tion instruments are installed by the distributor or dealer and not by the boatbuilder or manufacturer If you re buying a used boat you can bet that there are numerous components installed by the previous owner who may or may not have known anything about electricity You can also bet that even if your new boat came with a comprehensive wiring dia gram none of these aftermarket add ons are ever noted on it With the cost of a boatyard electrician well past the 100 an hour mark in some areas it s easy to see why electrical repair bills can get so high With every job done at the boatyard a substantial portion of the bill goes toward paying the electrician to figure out the wiring system Thus learning to do your own electrical work is one of the most cost effective ways that you as a boatowner can spend a few hours Once you finish this book you ll be able to make your own basic repairs and additions You may even pay for the book with your first job As a first step in becoming a competent mari
76. of marine parts and me chanic s tools You can find the stores nearest you at www napaonline com In my view Snap On produces the finest tools for the mechanic available anywhere in the world If you are looking for the best check out www snapon com Like MAC Snap On distributes through local mo bile vendors but the distribution network is world wide West Marine Call 1 800 685 4838 or go to www westmarine com Copyright O 2000 2007 by Edwin R Sherman Click here for terms of use Numbers in bold refer to pages with illustrations A abnormal instrument readings 148 49 abrasion protection 58 59 absorbed glass mat AGM bat teries 67 69 97 acceleration spark advance 106 110 acceptance absorption phase 98 accessories See direct current DC accessories Advanced Marine Electrics and Electronics Troubleshooting Sherman 155 AGC fuses 48 49 alternating current AC need analysis for inverter selection 171 73 overcurrent protection 162 63 164 165 174 ripple voltage test 93 94 safety 157 58 terminology 156 57 alternating current AC appli ances 171 172 173 alternating current AC circuit breakers 162 63 164 165 GFCIs 166 67 alternating current AC cir cuits 156 57 on boats 157 checking 167 70 color coding for wiring 158 59 compared to DC circuits 159 62 marine vs residential materi als 162 outlet connections 164 165 overcurrent protection 162 63 164
77. of this certification and will al ways promote the fact that they are certified so it shouldn t be too hard to locate one in your area Basic AC Safety Rules I could easily fill up two or three pages with safety rules that all of us should observe when working with AC but most of these rules are common sense A case recently came to my attention where an electrician who had forgotten his wire stripper was removing in sulation with his teeth Everything went fine until he tried to strip the hot black wire while holding on to the bare end of the grounded white wire He woke up in the hospital with a good part of his lips burned away Therefore one rule might be Always turn off the power before you strip wire with your teeth Another older case suggests another rule Never change a light bulb while standing in a bathtub full of water There are lots more but I have covered them all with rule number 10 below Here are a few others that apply specifically to boats 1 Use only marine grade products wiring terminal strips and connectors on your boat 2 Observe polarity at all times The orientation of the hot wire also referred to as the ungrounded conductor and the ground wire the grounded conductor and color code matches are all very important Reverse polarity can at the least cause certain equipment not to function and at worst it can destroy expensive gear 3 When working on the AC system disconnect the powe
78. often not taken seriously During my career I ve seen two batteries explode covering workers with acid In one instance we were able to flush away the acid so that the worker escaped injury What was his mis take He left a 4 inch wrench on top of a battery and it had come in contact with both the positive and negative terminals In the other instance the victim was permanently scarred His error He disconnected a battery charger from a battery without first turning off the charger The resulting spark ignited the hydrogen gas that had built up around the battery In a third less dangerous instance a battery sim ply exploded and coated the main saloon of a friend s liveaboard cruiser with battery acid curtains carpets furniture everything I m not sure what caused that one but I think he was attempting to charge a battery with low electrolyte Fortunately no one was on board at the time of the explosion so there were no injuries Battery acid is dangerous Battery safety rules are simple but must be followed gt Thoroughly ventilate the area around batteries Highly explosive hydrogen gas which can be ig nited with the smallest spark or cigarette ash is be ing produced when charging a battery Don t put tools on top of a battery when working in the area Metal tools can cause a short between the two terminals and will literally weld themselves to the battery The least you can expect is a spec tacular spark th
79. on the dia gram just as it s connected on your boat and don t forget to include the fuses using the fuse symbol shown in figure 2 1 that should be connected to the positive battery leads somewhere between the batter ies and the switch Now that you have the positive side of your bat tery system drawn it s time to fill in the negative side Find where all the negative battery cables are con nected at a common point on your boat This could be on a separate stud on a heavy duty terminal strip or on an engine or transmission bolt Draw this on your diagram roughly as you find it on your boat once again sketching in any mysterious components that you find attached but can t identify The next step is to locate on your boat the starter motor the alternator and the voltage regulator If you can t find a voltage regulator you most likely have an alternator with an internal regulator Draw Working with Wiring Diagrams little pictures of these items on your diagram making sure that you provide terminals for all the wires you see attached to each Next draw a three terminal switch that will represent your starter key switch These little drawings needn t be fancy just a little rectangle identified with a label will be fine Now that you have the alternator the starter the start switch and perhaps the voltage regulator drawn on your diagram follow each wire that s connected to each item on your boat and draw it on the
80. or improve for your m P P y p Battery single cell O O Switch DPST Circuit boat is just like that road map It orvoltage source O O double pole Circuit will provide us with the informa single throw tion to trace a route from start to Tt og O Switch PBNO finish in this case the electrical flow i O push button Voltmeter Z normally open through the circuits on your boat vey The trouble is unlike road maps which are reasonably consistent in FS Capacitor Ammeter Motor design and have that prominent key to tell you what the symbols JL mean wiring di i Resistor Voltmeter Earth g diagrams come in a ground variety of designs and styles and there is seldom a key to reference Fortunately most of the basic elec Variable a D Light bulb b EXIRET trical symbols are fairly standard resistor p 8 lamp N Soan and the others that you ll need for our wiring diagram aren t too hard Fig 2 1 Common wiring diagram symbols 13 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS good map Some of the most important elements of a good wiring diagram are as follows pm Every wiring diagram for a small boat should be simple enough to be easily read and understood even by those of us who don t have an engineering degree The relative location of all electrical components on the boat must be shown Each component of each circuit must be shown with all relevant specifications The size and the type o
81. plastic is that it will never rot and it won t crack on the grain as do hardwood blocks These plastics are easy to work using regular woodcutting and forming tools Figure 12 11 illustrates a through hull mount ing with a fairing block Transom Mount On smaller boats the transom mount is usually the simplest and easiest of the three choices for trans ducer installation Figure 12 12 illustrates a typical installation Virtually all fiberglass production boats built to day use a plywood cored transom To prevent water from migrating into the core which will eventually Installing Marine Electronic Equipment rot the wood mounting screws and any holes drilled for routing the transducer cable through the transom must be sealed with 3M 5200 or a similar product In addition the mounting bracket must be set up so that the face of the transducer is pointing straight down as with the two other installation options Troubleshooting Fish Finders and Depth Sounders For several reasons fish finders and depth sounders are a bit more finicky than other types of electronic equipment They are sensitive to voltage and will only operate within a certain voltage range typically between 10 5 and 16 5 volts for a 12 volt unit So that all night fishing trip at anchor could conceiv ably drain your battery to below the minimum 10 5 volt level A faulty voltage regulator on your boat could also allow the upper 16 5 volt threshold to be rea
82. plate 3 Screw 4 Wiring har ness 5 Hose guard 6 Access plug 7 Ignition system housing 8 Bracket 9 Lock washer 10 Bolt 11 Cap 12 Spark plug 13 Cap 14 Cables 15 Ignition coil 16 RPM Limiter 17 Screw 18 Wiring hold down 19 Screw 20 Grommet 21 Lock washer 22 Bolt 23 Washer 24 Screw 25 CDI unit 26 Harness sheathing 27 Screw 28 Stator plate 29 Flywheel ring gear 30 Flywheel 31 Woodruff key 32 Lock washer 33 Nut 34 O ring cover seal 35 Screw 36 Outer cover 105 106 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Fig 7 4 Photo of Deutsch type gang plug These offer the best waterproof connections and are now widely used by en gine makers traditional ring eye terminals and studs to connect circuit components should after assembly be sprayed with a corrosion inhibitor like Boeshield T 9 Figure 7 4 shows a modern Deutsch plug with the silicone rubber sealing rings that make these plugs an excellent choice for the marine environment Apply a coating of dielectric grease to the metal surfaces of all spark plug wires before they are plugged in Also make sure the rubber boots on both ends of the plug wires are supple and are pushed down around the towers on ignition coils and distributor caps as well as over the spark plugs Any heat hardened or cracked boots must be replaced The biggest cause of prob lems with the ignition wires to the spark plugs is dam age from chafe and e
83. plugs check the coil and bypass circuit to the coil positive terminal and check the wiring Also check the engine timing and plug wire rout ing and the tachometer and related wiring Some of the items mentioned here such as engine timing and tachometer wiring have not yet been dis cussed but I will cover them in the following sec tions This list is a guide for inboard and inboard outboard IO engines only Use it for sorting out your thoughts as you approach a problem You must work with the specific information for your ignition system if you expect to be successful as an ignition system diagnostician I will discuss two of the most common inboard engine electronic ignition systems the MerCruiser Thunderbolt IV and Thunderbolt V Other widely used systems with similar design and features are made by Prestolite and Delco Use this chapter as a primer on electronic systems in general and refer to the workshop manuals for the specific information you need to troubleshoot these other systems MerCruiser Thunderbolt IV and Thunderbolt V Systems With about 75 to 80 percent of the market at this writ ing MerCruiser is the largest producer of gasoline fueled inboard engines in the world The Thunder bolt series of ignition systems has been quite popu lar over the years and for the last 15 years the Series IV and Series V systems have been the mainstay of the MerCruiser line The Thunderbolt IV system Maintaining Marine Ign
84. point indicated Primary Control Unit Switched by 102 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS the spark plug for the cylinder that needs to be lit off at that time Figure 7 1a on page 101 illustrates the flow of cur rent through a typical electronic ignition system show ing both the primary and secondary sides ofthe circuit Distributorless Ignition Ignition systems on gas inboard engines have evolved to a system that eliminates the distributor entirely These systems which are widely used in automotive applications have been adopted by MerCruiser Cru sader and others and are becoming the norm Dis tributorless ignition systems DIS offer some distinct advantages particularly the elimination of the distrib utor cap and rotor parts that require periodic main tenance and inspection A short list of the advantages of a DIS is gt No timing adjustments are needed it s done auto matically via the engine computer No moving parts to wear 9 No distributor to accumulate moisture and cause starting problems DIS also allow more precise timing and spark con trol over the full spectrum of engine rpm all con trolled by a mini computer The primary components of this system are pm Engine control module computer pm The ignition module which is interfaced with the engine module pm A magnetic sensor or triggering device that is keyed to either the engine flywheel or the engine
85. precise spec ifications on spark plugs so all you have to do is keep the plugs clean and properly gapped and replace Maintaining Marine Ignition Systems them when or before it becomes necessary I ll dis cuss changing plugs later on Regulations Regarding Ignition Systems I need to make several important points before con tinuing much farther into this chapter Most of the ignition systems in use today employ solid state de vices for control In some cases the best approach to troubleshooting will be to consult this book along with the workshop manual for your engine You may find that the only way to be certain of a diagnosis is to try a new component At that point it s time to call in a pro unless you re quite experienced and have full confidence in your mechanical ability When that s the best bet I ll point it out in the text At the very least after reading this chapter you ll be able to perform all routine maintenance on your boat s ignition system When you do need to call a mechanic you ll be able to intelligently talk about your problem Ignition system components used on boats fall under the jurisdiction of the U S Coast Guard and must be manufactured in accordance with their regulations Use of ignition parts that do not comply with these rules and regulations could re sult in a fire or explosion Don t even think about cheating on this by buying less expensive automotive replacement parts These may look the s
86. rapidly re versing thus inducing alternating current Because your battery needs to be charged with direct current this alternating current is passed through a bridge rec tifier where it s converted to usable direct current Why you may well ask do we go to all this trou ble to generate alternating current and then convert it back to direct current when an old fashioned gen erator would develop direct current without all the complicated circuitry of the bridge rectifier The an swer is efficiency An alternator can be built much Battery Charging Systems lighter than a generator and it will produce much higher currents than a generator of the same size It s ironic but true it s easier and better to produce alter nating current and convert it to direct current than it is to produce direct current straight from a generator Engine Driven Marine Alternators There are four broad categories of engine driven charging systems commonly found on boats today The chances are better than good that your boat s charging system will fall into one of the following groups 1 Outboard engine with remote rectifier and no voltage regulator 2 Outboard engine with remote rectifier and voltage regulator 3 Inboard or stern drive with remote voltage regulator 4 Inboard or stern drive with integral voltage regulator Alternator Problems Most problems with alternators are best corrected by removing the alternator from the boat an
87. report Finally with a twist of the starter switches the engines rumble to life and I am away for a day on the water None of this would happen with out the boat s batteries so let s take a close look at this most extraordinary and complicated contrivance How Batteries Work The Basics In direct defiance of the wishes of one of my editors I have decided to avoid a long dissertation on the chemistry that boils between the plates of your boat s batteries For one thing battery chemistry is a com plicated subject that would take many pages to prop erly discuss And for another thing it s not what this book is about I want you to know how the electrical system on your boat works and what to do when it doesn t The internal chemistry of the battery just isn t that important However for you technophiles who do want to delve deeper into the chemical mys teries of the modern voltaic storage battery I would refer you to your public library and the Encyclopedia Britannica where you ll find an exhaustive and ex hausting article on the subject Basic Chemistry Unfortunately I am not going to be able to avoid chemistry altogether and there are a few underly ing principles with which you should be familiar For our purposes it s enough to know that the sev eral types of storage batteries you might find on your boat all work on the same system Batteries are di vided into cells with plates of two dissimilar metals surrounded by a
88. should however be familiar with the basic underlying principles of alternator operation just enough to understand what is going on as your pre cious batteries are being recharged Before I go much further here are some terms you need to know that define components common to all alter nator systems gt Stator windings These are the windings that produce current inside the alternator The stator is the stationary part of the alternator inside which the rotor rotates which makes these two terms easy to remember Rotor The rotor is the magnetized coil that spins inside the stator windings The coil on the rotor is known as the field windings This is easy to re member because field is just a shortened form of magnetic field The rotor provides the magnet ism that induces alternating current in the stator Diode A diode is an electronic check valve that allows electrical current to flow in one direction and blocks it from flowing in the other Diodes are mounted inside the alternator as part of a bridge rectifier circuit Bridge rectifier This is the internal circuitry that uses silicon diodes to convert alternating Copyright 2000 2007 by Edwin R Sherman Click here for terms of use current created in the stator windings to direct current usable for recharging your batteries Voltage regulator This critical device adjusts the current in the field windings to match your al ternator s output and the needs of y
89. sized wire to feed an auxiliary fuse panel connecting all the onboard equipment you want feeding directly from the battery rather than through the main distri bution panel Locate it far enough away from the bat tery to avoid the corrosive fumes but close enough to comply with the ABYC standard Companies like Ancor Newmar and Blue Sea Systems make per fectly suitable fuse panels for this purpose Automatic Float Switch Once you ve decided how you re going to provide power to your new circuit you need to decide if you want to install an automatic float switch for your new pump Since most installations do use an automatic float switch of some type I ll illustrate that setup here Installing Your Own DC Accessories Figure 9 5 shows the basic parts to this new cir cuit laid out and ready for the installation of the pump and the switch Tools Tools you ll need for this installation will include the following some of which are assembled in figure 9 6 bm awire cutter a wire stripper and a set of quality crimping pliers described in chapter 1 b gt aheat source for shrinking the heat shrink tubing a Bic lighter will do the job but a heat gun is bet Fig 9 6 Electrical tools needed for a bilge pump installa ter and safer tion gt slotted and Phillips head screwdrivers to match the turers of bilge pumps tends to be larger than what is screws you ll use to mount the panel float switch 8
90. small consoles to work with and al most always have a compass mounted right in the middle of the area just in front of the helm This is usually right where you want to mount that new ra dio or fish finder to keep it in plain view and easy to use Virtually all of the electronic equipment you re likely to want on board emits some amount of mag netism Remember from chapter 3 how any current flowing through a conductor creates a magnetic field This magnetism is sure to upset the accuracy of your compass and in some cases this compass er ror can be quite pronounced Several years ago without giving the location much thought I installed a new VHF radio on my Copyright O 2000 2007 by Edwin R Sherman Click here for terms of use boat I put it about 8 inches from my steering com pass right where the old one had been The new ra dio worked just fine I could see the controls they were easy to reach when I wanted to transmit and the speaker was close by so I could easily hear any incoming transmission The problem with my com pass didn t show up until several weeks later when I was traveling in fog and had to use my GPS to navi gate to the breakwater entrance to my homeport I knew the GPS waypoint was accurate so all I had to do was follow the compass course to the entrance It was then that I discovered that my compass was 14 degrees off Sure enough the new VHF speakers had much larger magnets in them than my original spe
91. ten have ratings of 360 amps continuous and 600 amps intermittent Be certain that the switch you pur chase is intended specifically for battery switching Battery switches available today have an impor tant feature known as make before break When switching from one battery to another the contact inside the switch connects the battery you re selecting before it disconnects the battery you re deselecting Without this feature your alternator could be de stroyed in an instant An alternator cannot stand even a momentary disconnect from the battery it is charging without damage Therefore never shut your battery switch off with your engine running An alternator is essentially a dumb device Without the load of a battery on it while it s running it will auto matically surge to its full output burning out the diodes inside it Maintaining battery switches is not something many people think of but the most common cause for failure of these switches is loose connections on the back of the switch These loose connections cause resistance which in turn causes heat With starter motor current trying to get through the loose connection that heat is often enough to actually melt the plastic housing around the cable studs This effectively loosens the stud in the case and destroys the switch The answer here is to occasionally check the tightness of the connections at the back of the switch In fact some switch manufacturers even rec ommend
92. the area around the box must be vented to out side air pm All battery boxes and cases must be constructed of nonconductive noncorroding materials gt Batteries must be secured so that the fasteners can not come in contact with battery electrolyte pm Everything within 12 inches of the battery must be covered or in some way protected so that it s com pletely nonconductive This is to prevent any acci dental short circuit between the item and the battery terminal An easy way to satisfy these standards is to install all batteries in a commercially made plastic battery box such as the one shown in figure 5 5 Pre made battery boxes in a variety of sizes are available at any marine supply store Just remember to secure the box with the straps provided and make sure that the bat tery is well ventilated to outside air Battery Maintenance and Testing There are several situations that can cause prema ture battery failure but the most common by far is owner neglect The second most common cause of a battery cashing in its chips before its time is the mal function of the charging system However I classify even this as owner neglect because the conscientious skipper should monitor this charging system closely enough to catch a malfunction long before it can per manently damage the battery Other common causes Fig 5 5 Typical plastic battery box of premature battery burial are using the wrong type of battery
93. the boatowner and will help to ensure that your generator is of the proper size and is performing as it should The basic trou bleshooting checklist at the end of this sec tion will help you to at least point the service technician in the right direction if you do have trouble with your generator Fig 11 21 A typical inverter monitoring panel the Xantrex Link 1000 Inverter Waveform On the subject of voltage output there is one addi tional point that needs to be made regarding invert ers Most but not all inverters produce what is known as a modified square waveform Shore based power supplies on the other hand produce what is known as a sine waveform Early inverters produced a standard square waveform This technical mumbo jumbo is all great infor mation for electrical engineers and of little value to boatowners except for several issues First older square wave inverters had trouble running things like TVs microwave ovens and older computers and could even damage or destroy these appliances Today s modified square wave and true sine wave inverters have pretty much licked that problem and the new inverters run just about anything The second problem caused by waveform is mea suring voltage and amperage As I mentioned earlier in this chapter and in chapter 3 the meter used to measure voltage from an inverter should be of the true RMS variety to give the best results Typically modified sine wave inverter
94. the bronze props on that big sportfisherman in the next slip Copyright 2000 2007 by Edwin R Sherman Click here for terms of use POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS me You ll also need an electrical conductor or a series of conductors so arranged that electrical energy can travel from the source to the place where it s needed to the light bulb in the galley for example then back again to the source As I mentioned above nearly anything can serve as a conductor even the air we breathe normally an excellent insulator serves as a conductor when the charge of electrical energy is massive enough as anyone who has wit nessed the flash of a lightning bolt can attest pm Although they are not required to make an electri cal circuit function there is a practical requirement in most circuits for a fuse or circuit breaker Circuit protectors defend circuits from destructive forces of excessive amperage a subject we will deal with in some detail later on p gt Also not required but present in most circuits is some sort of switch to turn the electrical energy in the cir cuit on and off or to direct it to the place where we want it to go to work for us Sometimes the circuit breaker serves as a switch but there are many other types of switches that we will discuss later on Finally all functional electrical circuits need some sort of load or appliance The circuit load is both the reason for the circuit s exis
95. the fuse jumper s tool of choice Another less dangerous drawback to fuses is that they tend to be awkward to remove so that deacti vating a circuit is sometimes inconvenient This is es pecially true when the boatbuilder has located the fuse holder in the back of some obscure locker as often happens Here again those among us who are easily led astray might be tempted to work on a cir cuit while it s live instead of taking the trouble of re moving the fuse The answer to all these problems is to have a reusable fuse that incorporates a switch so the circuit can be easily shut down and this is just what a circuit breaker does Circuit breakers are available in only a limited range of sizes the most common being 5 10 15 20 25 30 40 and 50 amps AGC MDL and ATO fuses however are available in increments of 1 amp and even fractions of an amp This means that nearly all Wire and Circuit Protection Standards and Repair Procedures circuits on a boat need a combination of circuit breakers and fuses In most cases a circuit breaker will be used to protect the circuit and fuses will be used to protect each piece of equipment on the circuit A typ ical lighting circuit for example might have five sep arate 25 watt light fixtures wired in parallel with a 15 amp circuit breaker protecting the circuit and a separate 3 amp fuse protecting each of the five lights If a problem were to develop causing a current surge at any one o
96. the new circuit Copyright O 2000 2007 by Edwin R Sherman Click here for terms of use Length of Wire Next you should measure the wiring run from the distribution panel to the accessory and back to the panel Don t just measure a straight line from the dis tribution panel to the location of the new accessory and back again Make sure you measure the actual route the wire will follow It isn t at all unusual for the actual route of the wire to be double the straight line distance or even more Voltage Drop and Wire Size Remember that the longer the run the higher the potential voltage drop in your new circuit will be and the larger the wire you ll need to overcome it Before you continue decide now the extent of the voltage drop you re willing to accept Remember that the ABYC standards recommend no more than a 3 percent drop for any critical gear such as elec tronic navigation and communication equipment However a new cabin light could fall into the 10 percent category Personally I use the 3 percent standard in all cases Boatbuilders of high end boats usually use the 3 percent standard throughout their new boats However high volume price conscious builders will often use the 10 percent maximum just to save money which is how they can offer their products at affordable prices Many noncritical accessories will work just fine with the higher voltage drop but oth ers will suffer reduced performance Interior lighting
97. the other hand are built with heavy and comparatively thick plates and have much more lead in them than cranking batteries You can actually tell the difference between the two by lifting them They are designed to be discharged up to 50 percent of capacity and recharged over and over again without sustaining any permanent dam age Because of the heavier and thicker plates used in deep cycle batteries they take much longer to reach full charge than cranking batteries Therefore they aren t a good choice for a starting battery par ticularly where an engine will be started frequently and run for short periods of time Deep cycle batteries are perfect for use as the house battery in cruisers that will be anchored away from shore power for overnight trips or for fishing boats that will be anchored for long periods with the fish finder radio and beer cooler running Deep cycle batteries are designed to take abuse but even these can t be completely discharged and recharged continually without failing Thirty percent 70 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS of full capacity is generally considered a maximum level to which these batteries can be safely discharged Fifty percent maximum discharge however provides a major increase in the life of the battery Combination Batteries Within the last few years I have seen what could be the answer to the battery prayers of many owners whose boats are not clear candidates for eit
98. the rating of fuses and circuit breakers for different types of circuits under differing circumstances Some circuits must be protected with a fuse or circuit breaker that s no more than 100 percent of the total amper age handling limits of all the compo nents on a circuit and other circuits may have a fuse or circuit breaker rated as high as 150 percent of the total amperage One such division of stan dards is between motor circuits and nonmotor circuits Motor Circuits Motor circuits fall into a unique cate gory Starter motor circuits on boats are the only circuits that are exempt from the requirement for circuit pro tection The protection ratings for other DC motors fall into a gray area In a perfect world these motors would have a circuit breaker built in as in most AC motors you may be familiar with The little red reset button on the side of the motor is actually a cir cuit breaker However most of the DC motors you ll run into on board your boat do not have this type of Wire and Circuit Protection Standards and Repair Procedures protection So why are motors different from any thing else electrical found on board The answer to this question lies in the two major differences between motor circuits and other circuits First as already mentioned motors will draw a con siderable amount of additional current when they first start up Once the motor is running the current tapers off to a more reasonable and c
99. the shift in neu tral you ll also need 12 volts at one of the small ter minals on the solenoid All manufacturers use a color coded wire for this connection OMC and Mercury use a yellow and red one Remember that the black wire from the solenoid is a ground wire and not the one to check Use the test described ear lier to check for voltage at this point If 12 volts is found while the key is in start you know that the ig Fig 8 9b Checking voltage at the outboard solenoid with the key in the on position With this test you should get a reading near battery voltage nition switch is OK If you don t find 12 volts here trace the harness as for the other wires If no dam age can be found the problem is inside the control box Figure 8 9a on page 134 shows the solenoid ter minal being checked for 12 volts with the ignition switch in start Figure 8 9b on page 134 shows the positive wire to the starter solenoid being checked for 12 volts with the ignition switch on Other Outhoard Engine Starter Motor Problems In addition to slow starting or no starting some se vere mechanical problems may also cause a no start condition The possibility of extreme engine over heating and water getting inside your engine is real The symptom for either condition is a loud clunk Tracing and Repairing Starter Motor Circuits as the starter motor drive gear engages the flywheel only to encounter an engine that will not turn o
100. the terminal marked connection A shown in figure 8 7a on page 130 The wire on this terminal connects the solenoid to the ignition switch and should be identified in your wiring diagram The quick check to see if the switch is functioning is to look for a 12 volt reading at this terminal with the key on start Simply connect your meter with the black probe to ground and the red probe to this ter minal and have someone shift into neutral and turn the key to start If you get no reading when the key is turned to start the problem is probably within the control unit but not necessarily There could be corrosion at the remote control master plug or there could be a break in the wire connecting the plug assembly to the back of the boat Using your wiring diagram as a guide identify this solenoid feed wire Next disconnect the wire from the solenoid and identify which terminal it goes to in the plug assembly With your multimeter set to the low ohms scale check for continuity between these two points Using your alligator clips you may want to make an extended jumper lead to one of the test leads from your meter depending on the distance between the plug assembly and the solenoid You should get a reading of nearly zero ohms if this wire is intact from the plug to the engine If you get a high reading or a reading of infinity there is a break in the wire or a corroded connec tion between the plug and the engine In some cases this wil
101. the very least you ll be able to point the professional mechanic in the right direction and save on expensive labor charges As already stated each of your ignition coils is re ally two coils combined into one unit consisting of a primary winding and a secondary winding The trick is to identify which external coil wires and connec tions go to which coil inside the insulated case To do this you need the wiring diagram and workshop man ual for your engine Using the diagram in the manual as a guide check the resistance of each of the coil windings with your multimeter s ohmmeter If you find electrical continuity and normal resistance you can be reasonably certain your coil is OK If you find excessive resistance or if the meter indicates an open circuit within the coil then the coil must be replaced Figure 7 16 shows these tests on a typical out board engine high tension coil Remember though Fig 7 16 Using the ohmmeter to test the resistance through an outboard engine ignition coil testing for a short circuit to ground top and testing resistance through the coil windings bottom Make sure to get the proper specifica tions for your engine from the workshop manual that you must identify the correct wire connections and resistance values for these tests to work on your specific make and model of engine Whenever removing an ignition coil from your engine carefully note the location of any insulating wa
102. these plugs available and it s usually best to replace the entire plug assembly rather than to replace a sin gle connector within the assembly Replacing only a part of the plug rarely works and the watertight in tegrity of the plug is almost always ruined Duplex and triplex assemblies are available at the major sup ply houses and repairing these may also require re placing both the male and female ends of the plug P E a Fig 4 30 A bunch of butt connectors at a harness repair point Taped and wrapped as it should be this would look like a snake trying to swallow a rat Fig 4 31 Staggered butt connectors at a harness repair point Using this approach to harness repair will give a much neater job 63 64 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Fig 4 32 Butt connection with waterproof heat shrink tub ing This is the highly recommended method for joining two wires together especially in the area of the bilge Finally whenever you join two wires with butt connectors I strongly recommend that you seal them with a length of heat shrink tubing to make a water tight connection These terminals are famous for trapping water and corroding Figure 4 32 shows a butt connector that has been crimped and sealed with heat shrink Heat shrink tubing is now available with Fig 4 33 Stepped type butt connector These are the only way to go when you
103. to determine if the wire has a fuse in it as it should Replace the fuse if it s blown and recheck for voltage If you still have no voltage reading you could have a faulty ignition switch or bad wiring Further investigation will be needed but the charging sys tem problem you were originally checking out is in Fig 6 7 Checking for field excitation voltage at the alterna tor Remember the ignition key must be switched on when making this test You should get a reading of approximately 12 volts The meter red lead is connected to the F terminal and the black lead to a good ground in this case the GND terminal on this particular alternator The key switch isn t on yet but a reading of about 12 volts will show on the me ter if all is well all probability not with the alternator but with this wire If you read battery voltage at the alternator there is an internal problem with either the alternator or possibly the regulator Either way these units must be removed and sent to the specialty shop men tioned earlier Figure 6 7 shows the field excitation voltage being checked Remember the boat s ignition key must be in the on position when checking for field voltage Charging Amperage Test Voltage is not your only concern when you re check ing alternator output It s possible that your alterna tor amperage has diminished from its rating Reduced amperage can be caused by a fault in the sta tor windings inside the alternat
104. using a specialized torque wrench to en sure proper tightness Battery Isolators The next commonly found component in multiple battery systems is the battery isolator By using these isolators correctly we can eliminate the problem of batteries discharging into each other Isolators use heavy duty diodes which only allow electrical flow in one direction to separate batteries preventing one from discharging into the other It s important to separate batteries for several rea sons First one of the characteristics of batteries is that a fully charged battery will try to recharge its weaker brother in a system So if you have a two battery sys tem and one battery is discharged with the battery switch left on both the first battery will discharge into the second one until they reach the same volt age The ideal system will prevent this but it involves installing a battery isolator Battery isolators use a group of diodes which are electrical check valves that allow electricity to flow in only one direction Isolators are installed between the batteries on a system to prevent a charged bat tery from trying to recharge a discharged battery to which it s connected Isolators are an excellent addi Batteries and Battery Systems tion to any low end multiple battery installation Figure 5 9 shows a typical 70 amp two battery isolator Isolators need a little care just like the other parts of your battery system Isolat
105. using your multimeter to check for AC volts you need to remember that AC and DC volts are dif ferent as far as your meter is concerned With either volts or amps you must switch to the AC function on your meter before making any checks If your meter is self scaling auto ranging the next step is to simply insert the leads into the appropriate sockets and take a direct reading on the meter as shown in figure 11 11 Note that in the diagram the meter s red lead is inserted into the smaller of the two slotted holes and the meter s black lead is inserted into the larger Don t forget to turn on the appropriate branch breaker before making this test If your meter is not self scaling make sure you select the appropriate scale for the voltage you re expecting to read When verifying voltage at an appliance a hot water heater for example that s hard wired into the circuit permanently installed rather than plugged into an outlet you ll need to get at the terminals in the junction box on the appliance With the branch breaker for the appliance turned on check for proper voltage at the appliance by touching your red meter probe to the terminal on the black AC wire and the black meter probe to the terminal on the white AC wire Simply take a direct reading In fig ure 11 12 the AC voltage supply to a typical marine hot water heater is being verified 3 e KEA x SEY M t Black Red
106. variation for watts the unit of electrical power If needed go back and refresh your memory on this process because the wattage equation really has some practical use when dealing with AC In the United States as a requirement of the Un derwriters Laboratory UL rating of AC equipment each electrical device must be marked with either the operating voltage and amperage or the operating voltage and wattage Typically wattage is given Knowing this you can easily find out the amperage of a given appliance by dividing wattage by the oper ating voltage This vital information is step one in the determi nation of overcurrent protection ratings as well as wire sizing No adjustment or de rating of the ampacity of the conductor for length of wire run is necessary as it is with DC circuitry With AC a different criterion comes into play Heat generated by whatever electrical resistance is present will require de rating the wire gauge Bundling of AC conductors requires that wire sizes be increased Also as with DC wires routed through engine rooms must be larger than those used out side the engine room to deal with the higher tem peratures Figure 11 2 shows what a typical bundle of AC ca Wire tie Fig 11 2 An AC wiring bundle Alternating Current and AC Equipment bles would look like in your boat Figure 11 3 isa table from the ABYC s section E 11 showing the am pacity of a typical length of triplex A
107. what went where and how When something went wrong I could tell from a quick study of the diagram what the most likely cause of the problem might be and where to go to fix it Naturally when I switched to the marine field and started working on boats the first thing I did was reach for the trusty wiring diagram Alas there were no wiring diagrams at least none that were comparable to those I had been accus tomed to Troubleshooting a defective electrical sys tem which had been so straightforward with automobiles became a study in frustration and con fusion Just locating components and determining which wire did what became a job for Inspector Sherlock and his trusty Watson or in this case In spector Sherman and his trusty multimeter Until only recently boatbuilders generally have done a rather poor job of creating usable wiring dia grams for their products Some supply only partial diagrams while others don t supply any at all or simply pass on to the buyer the one provided by the engine builder On the other hand some builders go to the opposite extreme and provide diagrams that are masterpieces but you have to be an electrical engi neer to interpret them They are far too complicated to be very useful for the occasional boater electrician and can even be confusing for the professional An electrician working on a car with a decent wiring diagram can usually go directly to an electri cal problem and fix it with a minimum
108. when a diode being checked with a meter using the regular ohms scale shows no continuity in both directions the diode is fine but the meter just isn t up to testing diodes The problem is that you don t have any way of telling if the fault is with the diode or the meter If you can only afford one meter make sure that it has diode checking capability The diode scale will work with nearly any diode you may encounter in marine work The most common Selecting and Using a Multimeter diodes you ll need to check are in your battery iso lators in your alternator and on any solar panels you might be using to keep your batteries topped up We will talk more about diodes in a later chapter Continuity Alarm Be sure to select a meter that has an audible alarm to indicate continuity on the ohms scale This alarm usually consists of a high pitched beep that signals the user that the meter is reading a resis tance value lower than infinity This simple feature really comes in handy when you re in a tight spot where you can barely connect two wires and can t see the face of your meter Make sure that you can actually hear the signal Some of the alarms use such a high pitch that those of us whose hearing isn t perfect can t detect it The alarm is used while checking for continuity through a circuit where the actual resistance in ohms is of minor concern Knowing for a fact that the cir cuit you re testing doesn t have a break in it is all t
109. with temperature So a battery that can put out an equal amount of amper age cranking at temperatures 32 colder than the competition is theoretically a more powerful battery What does all this mean Simple Be careful Do your homework and know what you re buying before you pay your money Manufacturers constantly play games with these numbers If you re getting your bat teries at the local Sears or KMart don t expect the floor people to know any more than you do about battery ratings Typical CCA ratings for starting gasoline engines are shown in the following table Diesel engines depending upon the type of starter motor and actual engine displacement can n 72 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Battery CCA Ratings for Gasoline Engines Engine Size CCA Rating Fourcylinder engine 450 CCA Sixcylinderengine 550 CCA Small V8 350 cubicinch 5 liter 650 CCA Large V8 454 cubicinch 7 4Hiter 700 CCA theoretically require twice as much amperage capac ity as the figures above When in doubt consult the engine builder for the exact specification Again if you have a cruiser with a lot of aux iliary equipment you ll need a battery bank comprised of deep cycle batteries Use the amp hour per day for mula above to calculate the total amp hour capacity Battery Safety Safety considerations around lead acid batteries are
110. 13 14 galvanic isolator 179 GPS receiver 190 191 need for 12 outboard engine remote key 120 poor quality 15 radar 192 shore power 159 160 single pole AC circuit breaker 165 symbols 13 14 tachometer 150 temperature fuel and oil pressure gauges 153 wiring harnesses checking for continuity 132 33 with in line fuse holder 183 junction boxes 20 22 repairing 63 securing 58 59 60 for transducers 187 88 workshop manuals 103 116 118 124 125 132 176 X Xantrex Link 1000 inverter monitor ing panel 174 175 multiphase smart charger 99 Z zone of magnetic separation 145 181 182 209
111. 146 Chapter 10 Engine Instrumentation Problems and Solutions Often taken for granted many times ignored on many boats that s the general lot of the vast array of expensive and delicate engine and navigation in struments The truth is that all your instruments should be taken quite seriously and considered an important part of the safety equipment on board your boat If your engine suddenly stops running 20 miles from shore you could be in serious dan ger That incoming thunderstorm could catch you in gale force winds or a strong current could push you into shoal water before you have time to set an anchor It is very important to monitor your instru ments constantly because they may provide the early warning you need to avoid this sort of emer gency Your instruments are also the primary com munication channel between you and your engine and they will keep you informed about just what is going on inside that very expensive and important piece of mechanical apparatus Understanding what the instruments are trying to tell you is also important It doesn t do much good to look at instruments if you don t know what all those dials and numbers mean For the be ginner misinterpretation of instrument readings can lead to a lot of false worries For example on dual helm boats different instrument readings for temperature oil pressure and rpm are not at all uncommon between helm stations The same is true with the instrum
112. 166 Checking Voltage Continuity and Polarity on AC Circuits 167 Selecting a DC to AC Inverter 0 0 cee eee eee 170 AC Cie 10 6 anes ee ee Re 175 Galvanic Isolators eene kt ese ertt Rer ete ee 177 Chapter 12 Installing Marine Electronic Equipment 180 El ctronic Gadgetry oe ic See ees a eu rere rete hene p 180 Universal Installation Details 00 cee eee eee eee 180 Power Supply ec sis ee p eer e eR rh eens 182 Installing a VHF Radio eee cee eee eee 183 How Much Can Gain 0 eee eee 184 The Coaxial Question ccc ccc cece eect een ee 184 Installing a Fish Finder or Depth Sounder 186 Installing a GPS Receiver 0 eee eee eee 190 Installing Your Own Radar 0 eee eee eee eee 191 En A C E E 193 RESOUECES dr ecrire iUe ACRI d EUR Eia d Rer aane oeta de 200 lode e T PLE 201 Forewortl to the Second Edition Itcan arguably be said that harnessing the electron has been one of humankind s crowning achievements For thousands of years people including those who have sailed the seas have been fascinated by light ning static electricity and harnessing light Early hu mans must have wondered how to put that kind of power to practical use But it wasn t until the close of the 18th century that the path to everyday use of electrical power would begin to have a profound and lasting impact the world over including at sea We all kno
113. 18 18 18 18 14 14 14 14 18 18 18 18 18 16 14 12 12 12 18 18 18 16 16 14 12 12 10 10 18 18 16 16 14 14 10 10 10 10 18 18 16 14 14 10 10 10 8 18 16 14 14 12 8 8 8 16 14 14 12 12 6 16 14 12 12 10 14 14 12 10 10 14 12 12 10 10 14 10 10 10 14 10 10 8 NNN EH OD COO MNNMRAAAODO TO TO TO IO 8 i AAO M TION fo BOO Fig 4 4 Table XI from section E 11 showing conductor sizes for a 10 percent drop in voltage O ABYC 45 46 TYPE SO SOW ST STW SJO SOW SJT SJTW SJTO SJTOW POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS continued from page 43 through with several tables to help decipher these secret codes From ABYC section E 11 we see temperature rating codes for flexible cords in figure 4 5 and insulation char acteristics and temperature ratings for typical wiring conductors in figure 4 6 Another table shown in figure 4 7 on page 48 shows the allowable amperage for various sizes of wires used inside and outside engine room spaces Notice that the amperage decreases inside engine rooms where expected temperatures are greater than outside temperatures Use this table to determine the size of conductors for low voltage DC systems only AC wiring uses different criteria The infor mation on this chart must be compared to the infor mation in the charts shown in figures 4 3 and 4 4 Always use the largest wire gauge indicated by the two charts for a given amperage based on the length of the w
114. 5 amps falls below the 5 amp minimum column in figure 4 3 on page 44 Remember to always round up in wire size and use the 5 amp column calling for a 12 AWG wire for a 30 foot run As soon as you move over to the 40 foot column the table calls for 10 AWG wire If the run were say 32 feet I would stick to the 12 AWG because you have already rounded up once Also remember that safety related electronic equipment will always fall into the 3 percent voltage drop category for wire sizing Much of this equipment particularly fish finders but other gear as well is designed to work in a fairly narrow voltage range See chapter 12 for more details on this subject Your new CD player should be tied into your main distribution panel just like the cabin light already discussed Since it falls into the general equipment category the use of duplex wire with red and black or red and yellow wires will keep the feed wire in compliance with the ABYC s color coding scheme A 10 amp circuit breaker or fuse at the panel will be a good choice here as long as the manufacturer supplied fuse and holder are not removed from the circuit Remember that the panel fuse will protect the wiring to the CD player and in the case of 16 AWG wire the basic ampacity for 105 C rated wire the most common is 25 amps so a main breaker rated at 10 amps is safe and in fact conservative Since the factory supplied harness that came with the CD player probably cam
115. 6 67 207 208 testing tests continued high tension ignition coils 115 16 load 84 85 neutral safety switch 132 33 ohmmeter battery 38 open circuit voltage 84 outboard and PWC ignition 112 20 121 polarity 159 167 70 rectifiers 96 reverse polarity 159 ripple voltage 93 94 spark 112 13 spark plugs 113 14 spark plug wires 115 specific gravity 83 84 starter solenoid 126 27 stop switch 115 119 20 121 temperature sending unit 153 three minute charge 85 three step voltage 92 93 tilt stop switch 115 120 121 trigger coils 115 116 18 117 unregulated charging sys tems 95 96 voltage AC 167 69 voltage drop 31 34 35 128 130 32 water spray 115 116 wiggle 169 170 3M 4200 188 189 3M 5200 188 189 three minute charge test 85 three step chargers See smart chargers three step voltage test 92 93 through hull transducer mount 188 89 tie wraps and clamps 18 59 60 tilt stop switch testing 115 120 121 timing 110 See also ignition timing tools 10 11 See also specific tools for bilge pump installation 143 top dead center TDC 102 INDEX transducers 187 90 transformers 101 transistor radios for checking RFI 182 transom transducer mount 189 trigger coils 104 111 115 116 18 117 trim gauges 149 154 trip free circuit breakers 51 162 troubleshooting See also test ing tests AC generators 177 depth sounders 189 90 engine instrumentation 149 55 en
116. 7 measuring 34 36 37 rating for ATO fuses 49 50 testing 42 43 Ampere Andre Marie 6 ampere hours amp hours 70 71 171 73 ampere interrupting capacity AIC 51 amperes amps 5 6 7 8 19 71 72 analog multimeters 26 Ancor inductive ammeter 11 29 multimeter 29 30 ratcheting crimper 11 61 62 143 anode 65 156 antenna gain 184 185 antennas GPS 191 radar 191 92 VHF 184 85 191 appliances 2 AC 171 172 173 DC 8 136 46 ATO fuses 48 49 50 automatic float switch 142 201 202 automotive alternators 88 automotive batteries 66 average responding multime ters 26 base timing 110 batteries See also battery instal lation amp hour ratings 70 71 basics of 65 66 CCA and MCA 71 72 cost comparisons 68 69 cycles 66 68 69 dimensions 71 group sizes 71 maintenance and testing 74 76 75 safety 72 74 selecting 69 72 sulfated 66 67 testing 74 76 82 85 20 hour rating 71 types of 66 70 battery bank size determination inverter 171 73 battery boxes 73 74 battery cable ends soldering 60 battery cables 77 131 battery carrying strap 72 73 battery chargers ferro resonant 67 96 97 four step 96 growth in demand for 157 smart 96 97 99 testing 89 94 99 battery charging phases 97 98 battery charging systems See also alternators outboard engine 94 96 95 shore power 96 99 solar cells 99 symptoms 89 testing 91 94 battery combiners 77 82 battery h
117. 75 heat shrink tubing 18 64 168 heat shrink type crimp connec tors 141 heat sinks 80 144 horsepower 6 hot lead 156 159 hot water heaters 168 170 house battery 69 hydrometers 83 84 idle speed spark control 110 ignition coils 101 104 105 111 115 16 ignition control module 100 101 102 104 110 111 134 ignition problem quick check list 114 20 121 ignition protection 52 53 103 123 166 ignition sensors 108 9 ignition switch 133 35 134 ignition systems final checks and ignition tim ing 120 22 121 ignition problem quick check list 114 20 121 inboard components 100 103 101 102 maintenance of 103 104 7 106 MerCruiser Thunderbolt sys tems 107 10 108 109 outboard and PWC 103 4 105 110 20 121 regulations regarding 103 testing 112 20 121 troubleshooting 106 7 ignition timing 109 10 122 CDI unit 111 and engine problems 106 107 ignition wires 103 impedance 26 157 inboard ignition system compo nents 100 103 101 102 induction 29 87 101 103 4 111 12 156 inductive ammeters 11 29 30 36 37 93 169 inductive pickups 28 29 36 37 inductive voltage sensor 167 inside the hull transducer mount 188 installations battery 76 82 bilge pump 140 44 141 142 143 cabin lights 139 40 DC accessories 136 46 depth sounders 186 90 187 188 189 DGPS receiver 190 91 dual battery 57 58 79 81 electronic equipment 180 92 fish finders
118. 8550 3 All trademarks are trademarks of their respective owners Rather than put a trademark symbol after every occurrence of a trademarked name we use names in an editorial fashion only and to the benefit of the trademark owner with no intention of infringement of the trademark Where such designations appear in this book they have been printed with initial caps McGraw Hill eBooks are available at special quantity discounts to use as premiums and sales promotions or for use in corporate training programs For more information please contact George Hoare Special Sales at george hoare mcgraw hill com or 212 904 4069 TERMS OF USE This is a copyrighted work and The McGraw Hill Companies Inc McGraw Hill and its licensors reserve all rights in and to the work Use of this work is subject to these terms Except as permitted under the Copyright Act of 1976 and the right to store and retrieve one copy of the work you may not decompile disassemble reverse engineer reproduce modify create derivative works based upon transmit distribute disseminate sell publish or sublicense the work or any part of it without McGraw Hill s prior consent You may use the work for your own noncommercial and personal use any other use of the work is strictly prohibited Your right to use the work may be terminated if you fail to comply with these terms THE WORK IS PROVIDED AS IS McGRAW HILL AND ITS LICENSORS MAKE NO GUARANTEES OR WARRANTIES
119. AC and DC only If the meter is not self scaling you ll have to select a scale appropriate for your expected reading Figure 3 15 shows some typ ical current values for the equipment on your boat Using an Inductive Pickup If you have an inductive meter it may have several scales to select from Generally these meters will have a high and a low amps scale in addition to the usual selection of AC or DC As with the standard meter simply select the scale for your expected reading based on the chart in figure 3 15 Some inductive meters require the DC amperage scale to be cali brated before each use In this case with the meter set up and the jaws of the clamp closed just rotate the calibration knob until zero appears on the scale Now isolate a wire at the point in the circuit where you want to measure amperage This might in volve unbundling a bunch of wires or in extreme cases it might involve adding a short run of wire to a circuit If you must add a piece of wire to get a place to clamp your meter make sure the wire is large enough for the circuit and that the temporary termi nals are tight otherwise you might change the dy namics of the circuit enough to get an inaccurate reading Once you have a wire isolated simply clamp Typical DC Amperage Draws for On Board Equipment Amperage Draw Load range depending on unit OCHO teers REY TS 1 3A MIMO WMS cee vconotccouocveosoce 75 300 A QUTODIIO Tears parents ent E
120. C boat cable Remember that the green conductor does not normally carry current and is therefore excluded from the process Another common question that comes up has to do with routing AC and DC wiring in the same bun dle Although the ABYC allows this practice as long as the wiring in question is separated by an appropri ate sheath which can be the outside skin of a typical length of AC boat cable it s much better to keep AC and DC wires in separate bundles The possibility of cross induction remember any wire with current TABLE VIII A ALLOWABLE AMPERAGE OF CONDUCTORS WHEN NO MORE THAN 2 CURRENT CARRYING CONDUCTORS ARE BUNDLED TEMPERATURE RATING OF CONDUCTOR INSULATION 60 C 75 C 80 C 90 C 105 C CONDUCTOR omm ym 176 F m coe SIZE AWG n7 j 20 n4 20 mo 25 23 25 oe on NN RE EE og d w pone 20 iso 2s 195 30 6 35 2 om 25 J nes 25 ges oss za o oss s 33 s o9 m o9 oo o 9 5 p 9 T9 125 C 200 C eru 392 F s s pepe za CU 29 38 3 F3 m T 39 86 38 95 T5 j Outside engine spaces OS 2Inside engine spaces IS Fig 11 3 ABYC ampacity table for a single run of triplex O ABYC 181 182 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS flowing through it generates a magnetic field is real and may cause problems with sensitive electronic equipment as we ll see in the next chapter Marine versus Residentia
121. Charge Gravity LS e mene E 1 120 1O E S EEE ART 1 155 jT B RO 1 190 2 jp jo mm 1 225 12 6 or more ODE 1 260 1 280 reading you took above Open circuit voltage read ings can be misleading and give you a false sense of security due to a phenomenon known as the surface charge A battery in poor condition may give you a reading as high as 12 5 volts or more if it has been sit ting idle for a few hours However as soon as you try to crank your engine with this battery you ll hear that disheartening click click click sound that tells you there s a battery problem Load testing will give you some real answers about how your battery will perform when the chips are down An easy way to load test your battery requires no special tools and is quite conclusive Make sure all battery cable connections are clean and tight Next disable your engine s ignition system or if you have a diesel engine activate the fuel shutoff so the en gine won t start during the test To disable the igni tion system on a gasoline engine follow the workshop manual for the engine On engines built from about 1992 you should be able to disconnect either a plug at the coil or distributor to disable the ignition system Do not try to disable the ignition by removing the center high tension lead on the coil not only is this dangerous but it could damage the ignition system More on this in chapter 7 Once the ignition or diesel engine shut
122. D CIRCUIT BREAKER SOME ITEMS MAY HAVE SECONDARY OVERCURRENT PROTECTION AT THE UNIT FUEL VOLT TEMP OIL TACH 2 Sedome Coron CODES LACK O ORANGE BL BLUE P PINK BR BROWN PU PURPLE R RED G GREEN TAN T GY GRAY W WHITE LT LIGHT Y YELLOW ALARM 2 ENGINE WIRING HARNESS BATTERY ANTENNA STEREO 4 7 1S GAGYBLI s ACLAROUND LIGHT 16 GA BL 16 GA D 8L 16 GAGYL TTT SYMBOLS SWITCH DPST SWITCH SPST FUSE CONNECTION NO CONNECTION DC GROUND PLUG 16 GAG 16 GAGA Y 16 GA BR 16 GA D BL 16 GA BR NAVAGATION GH 16 GA GAY 16 GABR 16 GA D BL 16 GA BR W LIVE WELL eJI PUMP 2 4 4 14 Fig 2 2 A good wiring diagram with all of my listed key elements incorporated Working with Wiring Diagrams OPT NO 2 BATTERY 1 SHORE POWER Ii BREAKER SWITCH OPT AC OUTLET Fig 2 3 A typical poor quality diagram This is all that came with a sailboat that I purchased in the early 1980s to describe the electrical installation The problem is certainly not exclusive to sailboats components do refer to the glossary at the back of this book Wire Identification and the ABYC Color Code Identifying the wires that connect the various compo nents illustrated by a wiring diagram can sometimes be a challenge when you first get started The good news here
123. E TO ELECTRICAL SYSTEMS If you do find 12 volts at point 2 proceed to point 3 and connect the red probe to the hot side of the neutral safety switch which disconnects the starter motor when the transmission is in gear You should get another 12 volt reading If not the connection is bad or the wire between the starter button and the neutral safety switch has a break in it Repair or re place the wire as needed Next be sure the transmission is in neutral and move your probe to point 4 the output side of the safety switch Push the button and take a reading you should get 12 volts If you don t the neutral safety switch is defective or out of adjustment To check for proper adjustment unbolt the switch from its bracket allowing the switch button to extend fully If you still cannot get a 12 volt reading at point 4 the switch is bad and must be replaced If you do get a 12 volt reading adjust the neutral safety switch by repositioning it in its mount so that the shift link age extends the button as far as it will go If you do get a 12 volt reading at point 4 and the engine still won t crank move the red probe to point 5 at the battery terminal on the starter motor the connection with the large red wire With the engine in neutral press the starter button and check for 12 volts If you don t find it there is a poor connection or a broken wire between points 4 and 5 Repair or replace the wire as required If you do find 12 vo
124. Fig 11 11 Using a multimeter to check voltage at an outlet A useful tip to help you when working with AC circuit testing is to get two short lengths of heat shrink tubing at your local supply house one white and the other black Shrink the black piece around the red lead on your multimeter and the white piece around the black lead This will remind you that the black lead on the AC is the positive and the black lead is the neutral when working with AC It simply gives you a quick color reference to work with Slight variations in your meter readings are the norm when measuring AC voltage In fact a varia tion of as much as plus or minus 10 percent of the rated voltage is possible If your dockmates are all using the AC system feeding the marina simultane ously you can expect a lower voltage reading At peak usage times of the day usually around breakfast and dinner you can also expect lower readings AC generators on board could also con ceivably run to that much of a variation This vari ation is not indicative of any particular problem Fig 11 12 Using the multimeter to check voltage to a hot water heater terminal block and will not affect the performance of your onboard equipment as long as the 10 percent variation at the rated frequency either 50 or 60 Hz is not exceeded By the way multimeters that can read frequency have dropped considerably in price and are available for less than 50 If you re goin
125. HF and single sideband SSB radios and radar units the amperage re quirements for most new electronics are compara tively low so wire gauge is not too much of an issue Generally on small boats the length of the wire between the distribution panel and the equip ment is not that long so sticking with the same gauge wire supplied with the equipment usually 16 AWG will suffice Figure 12 2 shows a typical wire harness with an in line fuse installed as supplied with a Loran C unit As for the connection to your boat it s best to dedicate a circuit breaker at your DC distribution panel for instruments and designate separate positive and negative bus bars to connect your various pieces of equipment Not only can direct connections to your batteries be messy but they will add to the length of wire needed to power up your electronic gear Figure 12 3 on page 183 illustrates the best method to supply your equipment by creating a ded icated branch bus from your main distribution panel This way you can use bus bars that are adequately sized and the addition of more equipment later on will be a much simpler task Once your new gear is mounted where you want it Installing Marine Electronic Equipment the next steps are specific to the various types of equipment Now you have to think about other things such as antenna or trans e e ducer placement Installing a VHF Radio Your VHF radio should be the mainstay of your onb
126. Height Height Sft 10f 25 100 ft 250 h 5 ft 5mi 7mi Omi 15 mi 23 mi 10 ft 9 mi 10 mi 11 mi 18 mi 25 mi 30 ft 10 mi 12 mi 13 mi 20 mi 28 mi 60 ft 12 mi 14 mi 15 mi 21 mi 30 mi Fig 12 4 Antenna height versus VHF range high gain will have a pancake shaped radiation pat tern oriented flat with the surface of the Earth This can have a profound effect on your radio s transmit range without increasing the transmission power but too much gain can work against you especially if you re pitching and rolling in a rough sea The three commonly available antenna dB rat ings for boats are 3 6 and 9 dB Figure 12 5 on page 185 illustrates their approximate radiated wave pat terns Notice that the 3 dB antenna is radiating a broader pattern than the 6 and 9 dB antennas For this reason a masthead mounted 3 dB antenna is the best choice for most sailboats If the 6 or 9 dB an tennas were to be used the sailboat s radiated signal while heeled underway would either be aimed at the moon or the bottom of the ocean The best compro mise for a small powerboat is the 6 dB antenna It will provide the maximum range with a minimum amount of signal lost due to the boat rolling in a sea way For extended range many powerboats with dual stations will mount a 9 dB antenna for the radio on the upper station which is more likely to be used in a calm sea The radio in the lower station which is more likely to be u
127. IMUM NUMBER OF STRANDS tain 19 strands of wire whereas an AWG 10 gauge Type 3 wire will have 105 strands Type 3 YPE2 TYPE 3 wire will also have a slightly lower resistance for a given gauge than a Type 2 wire Wire Size Once you have determined the type of wire to use on your Type 1 Solid conductor and stranding less than that indicated under Type 2 shall not be used Type 2 Conductors with at least Type 2 stranding shall be used for general purpose boat wiring Type 3 Conductors with Type 3 stranding shall be used for any wiring where frequent flexing is involved in 205 500 normal use NOTE l1 Metric wire sizes may be used if of equivalent circular mil area If the circular mil area of the metric conductor is less than that listed the wire ampacity shall be corrected based on the ratio of the circular mil areas For comparison of conductor cross sections AWG and ISO See AP TABLE 2 2 The circular mil area given is equal to the mathematical square of the diameter of the AWG standard solid copper conductor measured in one thousandths of an inch The area in square inches The circular mil area of the stranded conductors may differ from the tabulated values and is the sum of the circular pi circular mils 4 1 000 000 mil areas of the wires strands in the conductor project and in nearly all cases this w
128. L SYSTEMS content soft water is fine for batteries some is terrible The best bet is to check with a local battery shop and ask about their experience with the local water gt Keep tabs on both your engine s alternator and your boat s 110 volt battery charger if you have one Overcharging or undercharging is damaging to any battery Overcharging will boil the electrolyte and rattle the lead off the plates Undercharging will al low the lead sulfate to permanently harden reduc ing the surface area of the plates A sulfated battery will not develop full power and will eventually have to be replaced Battery Installations There are a number of ways to hook up and com bine batteries For the small open boat the choices are fairly simple and easy to understand But if your boat is a medium sized cruiser with twin engines and both a bank of starting batteries for starting the en gines and a bank of house batteries for supplying your needs while away from the dock the battery systems can get fairly complex I will only attempt to present the most common systems here First refresh your memory on series and parallel wiring hookups as we discussed back in chapter 1 These two methods of connecting battery cells and batteries are the primary methods builders use to alter system voltage and amp hour capacity Also you need to know a little more about battery charac teristics To create a 12 volt lead acid battery man ufactu
129. Malestrom Powerboater s Guide to Electrical Systems Second Edition Maintenance Troubleshooting O onan and Improvements a a EET Nin your boat s DC and AC wiring E Diagnose and fix problems o Install electronic equiprnefit e Get full instructions lt fordozens of lt E x 3E PEO TO OE r PoE r ri Ls t F m d E gt A a T c e T Or Sane s 7 x T Y d o pe om Aa B m na s u 7 oo d Mis P P uu P Sf x d ae ide Drap my r e e mE FED AA LT XE e jn Pe F xi x 2 7 PEDE wx RE II d 99 P P ta gt o f zm m y Second Edition Powerboater s Guide to Electrical Systems Maintenance Troubleshooting and Improvements Ed Sherman Camden Maine New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto The McGraw Hill Companies Copyright 2000 2007 by Edwin R Sherman All rights reserved Manufactured in the United States of America Except as permitted under the United States Copyright Act of 1976 no part of this publication may be reproduced or distributed in any form or by any means or stored in a database or retrieval system without the prior written permission of the publisher 0 07 159441 8 The material in this eBook also appears in the print version of this title 0 07 14
130. OME EQUIPMENT MAY NOT BE INSTALLED ON ALL MODELS 3 FUSEBLOCK POWER SUPPLIED BY ENGINE MOUNTED CIRCUIT BREAKER 4 SOME ITEMS MAY HAVE SECONDARY OVERCURRENT PROTECTION AT THE UNIT FUEL VOLT TEMP OIL TACH 2 ane ALARM 2 TRIM SWTICH TRAILER SWITCH COLOR CODES B ENGINE WIRING HARNESS START CIRCUIT NEUTRAL SAFETY AND EMERGENCY SHUTDOWN SWITCHES LOCATED AT SHIFTER ANTENNA STEREO 4 16 GABL 16 GA GY BL16 ACLAROUND 1 16 GA GYL LIGHT 16 GA D 8L SITAS NAVAGATION LIGHT SYMBOLS SWITCH DPST SWITCH SPST FUSE 7M i 2 2 PIN CONNECTION BLOWER NO CONNECTION 16 GA GAY i 16 GAGAY ilr DC GROUND BILGE PUMP 16 GA D BL 16 GA D BL 16 GABR 16 GA BR W LIVE WELL PUMP 2 4 Fig 2 8 How the bilge blower circuit would look on a good quality wiring diagram often seems like they do it just to confound us poor electricians The problem isn t with the use of the junction boxes they usually make a lot of sense The problem is where the boatbuilders choose to lo cate them I have found them inside lockers under floorboards behind drawers and medicine cabinets over headliners and I even found one behind a hold ing tank whereI couldn t get to it without a lot of un pleasant pumping These terminals are often located in spots so obscure that you would never find them without the help of some kin
131. Ohm 1787 1854 a German physi cist was one of the great early experimenters with electricity He left us with the simple but oh so im portant mathematical formula that bears his name Ohm s law helps us to understand the relationship between the measurable forces in electricity Once we are armed with a clear understanding of the re lationships between the different elements in this formula we will have made a giant step forward in our ability to understand and locate electrical prob lems As we work with this invisible thing called elec tricity we need to get used to dealing in an abstract way with the stuff We ll be taking a lot of mea surements with a multimeter and we will learn to translate these measurements into meaningful in formation Throughout the rest of this book I demonstrate the correct methods of obtaining ac curate electrical measurements with a multimeter and I try to provide an understanding of what these measurements mean First however we must get the definitions of a few electrical terms clear in our heads and then become completely familiar with this wonderful thing called Ohm s law Fig 1 5 A series parallel circuit as found on your boat The Key Players There are four terms that will continually crop up in any discussion of things electrical volts amps ohms and watts Each of these terms represents an electrical value and is named after an early experimenter in electricity These are the pe
132. R S GUIDE TO ELECTRICAL SYSTEMS The only other ingredients in your boat s batter ies are the grid an inert plastic frame on which the solid active ingredients are suspended in the elec trolyte and the case Lead dioxide sponge lead and lead sulfate are all very soft and fragile The grid gives the plates the support they need to stand up to vibration and shock The case of course contains the entire contraption and insulates one cell from the next The voltage from a single cell in a fully charged lead acid battery will always be approximately 2 1 volts called the galvanic potential regardless of the size of the battery A lead acid cell the size of your house is going to produce the same voltage as one the size of a peanut Thus when six of these cells are strapped together in series positive to neg ative and negative to positive you have a standard 12 volt battery Recent engineering innovations have allowed manufacturers to produce plates that are slightly thinner than their predecessors but just as electrically capable And due to advances in material technology the new plates are much stronger than the old ones Figure 5 1 shows the construction ofa typical 12 volt battery with cell dividers and internal plates Types of Lead Acid Batteries There have been enormous advances in battery tech nology in the past few years and the result is a large and growing assortment of batteries that you can use on your boat T
133. RAS 1 30 A bilge blower en eese eee tn NE 1 34 bilge OUND Ree ee UP UN NE UU DURS 1 5 5A Cabin antes ase t ERU paces 1 24 cabin light incandescent 0 1 4 A Tisi dorso eee eek Mu EE 0 1 1 04 TIUIDTESCETUC TREE E ETE T TETTE ETT TETTE 0 7 2 A ICMAT 2 socsenenesousoesceenesoss 4 5 A knofmeleleee reer TEE 0 1 1 0A LOTO GRS GARE E RETURN ERUNT N 1 24 MOCETCHOM DU eee eee 15 20 A mostheddilights ests npr S 1 2A TOUClips M eM ORDEN 4 8 A artt BO ios eee ooo oe aosceehoec 5 8 A TUnninQWi onis REED 3 6 A SSB TUI den nel E fate 1 2A transmit 25 30 A stereo tape deck CD 0 000000 1 2A VHE TOdo ARE E E ES 0 7 1 5 A transmit 5 0 6 0 A WOSTICOWMI DUI eee TEE TETTE 25 5 A wiper motor each RETE EET TETTE 1 5 5A Fig 3 15 A table showing typical current draws for power boat equipment Remember that these values are approxi mate and your equipment may vary from these values Always confirm the draw for your own equipment the meter around the wire with the equipment on the circuit turned on make sure the meter is oriented properly and read the amperage off the scale Ammeter use will be illustrated in a variety of tests throughout this book so if you re still uncer tain about how to use your meter the photos and diagrams that follow should set you straight Selecting and Using a Multimeter Measuring Resistance and Continuity All circuits and the components within them have so
134. S Antenna DC they are set up properly Fig 12 14 Wiring layout for a differential GPS DGPS receiver ered Follow the procedures described above for de termining any compass deviation and getting power to the receiver The big consideration is where to lo cate the GPS antenna GPS receivers use receive only antennas that need a clear view of the sky at all times Even something like a Bimini top or a windscreen can affect the integrity of a GPS signal Also radio transmissions from other electronic equipment such as cell phones VHF radios and single sideband SSB radios can affect a GPS signal The rules here are simple and not too hard to comply with even on small boats Basically the ideal is to maintain about a 1 meter separation or a little less than a yard between transmitting antennas and the GPS receiving antenna On most boats this is simply a matter of mounting the VHF antenna on one side of the bridge and the GPS antenna on the other Mission accomplished On boats with elabo rate gear mount brackets and airfoils just keep from mounting these antennas adjacent to each other GPS is a line of sight system between the an tenna and satellites orbiting overhead The antenna scans the sky via a conical pattern that points straight up So unlike VHF mounting an antenna too high can actually be detrimental to its perfor mance in a rolling pitching sea particularly if you have selected the improved accurac
135. Shore Side Underground Conductor Black Grounded Neutral Conductor White Boat side Optional Galvanic Isolator Black White Green To Engine Negative Terminal or its Bus Fig 11 6a Wiring diagram of a double pole breaker circled area that will simultaneously trip and open the black and white conductors O ABYC Alternating Current and AC Equipment rae E Shore Power 5 9 Cable Connector ca S oO Branch Circuit Shore Power Inlet Electrically insulated Breaker Typical Connection from the boat if isolator is installed Main Shore Power Disconnect Circuit Breaker 120 VAC Device 120 VAC Grounding Type Receptacle Shore Power Cable x E lt Tutte a ols aa 7 o 4 4 6 2 Pole 3 Wire Optional Grounding yes Plugs amp alent Polarity eceptacles solator Indicator To Engine Negative Terminal or its Bus Grounding Conductor Green Underground Conductor Black Grounded Neutral Conductor White Shore Side Boat side Fig 11 6b Here a single pole breaker circled area is allowed in the branch feeder to both the 120 volt AC appliance and the outlet because the boat is equipped with a polarity indicator The breaker will only trip the black conductor ABYC Black Green Wh
136. The smallest unit of a battery A 12 volt stor age battery has six cells charge coils Coils within a CD ignition system used to step up voltage supplied to the ignition coils chassis ground The case ground for metallic cased electrical equipment circuit A complete path for electrical flow from the positive power source or terminal to the negative or ground terminal A complete circuit has the following key elements a power source circuit protection most circuits a switch an electrical conductor a load or an appliance and a return conductor to ground negative circuit breaker An automatic switch that trips when the rated current flow through it is ex ceeded A bimetallic circuit breaker uses the dif ferential thermal expansion of dissimilar metals to open the switch circular mils CM Cross sectional area of a con ductor closed circuit turned on A complete circuit one that is coaxial cable Used typically for antenna leads and to interconnect marine electronic equipment This two conductor cable consists of an inner conductor insulated by a dielectric shield that is surrounded by a braided wire conductor and then insulated on the outside by another layer of nonconductive sheathing cold cranking amps CCA The number of amps a battery at 0 F 17 8 C can deliver for 30 sec onds and maintain a voltage of 1 2 volts per cell or more color coding One of several acceptable methods of identifying
137. War Today the standard of living across the globe has risen as more and more people experience the con venience of electric power at home school work and at sea If there is any doubt in your mind try to exist for one day without any influence of the power of the electron You ll quickly discover that you will literally be back in the Dark Ages In harnessing the power of the electron it was recognized early on that standards were needed for reasons of both practicality and safety For recre ational boats and yachts the American Boat amp Yacht Council ABYC a nonprofit industry member ship organization has been developing writing and updating the safety standards for boatbuilding and repair in the United States for over 50 years This includes electrical safety standards Over the past half century the ABYC has come to be known as the recognized global leader in ma rine safety standards research development inter national harmonization and co recognition ABYC standards are endorsed and used by the United States Coast Guard Transport Canada the National Marine Manufacturers Association NMMA Boat and Yacht Certification program the international community and by virtually every industry seg ment Over 400 of our member volunteers donate time expertise and research while serving on tech nical committees that develop and revise the ABYC standards and technical information reports The positive lifesaving imp
138. act of the ABYC stan dards cannot be overstated but perhaps none more so than in the area of wiring and electrical systems installation maintenance and repair of boats and yachts Proper electrical system design wiring type and size overcurrent protection wire termination power source management proper installation and integration of electronic sensing and control com ponents and the networking of all critical systems have and will significantly reduce injury and fatali ties caused by electrical fires and shock and damage Copyright 2000 2007 by Edwin R Sherman Click here for terms of use vii viii FOREWORD TO THE SECOND EDITION to watercraft components accessories and systems Simply put ABYC standards and in particular ABYC electrical standards save lives and property In addition to developing and disseminating in dustry standards the ABYC has taken the lead in ad vocating providing and promoting technical workforce professional development continuing education and technical workforce certifications Three courses that make extensive use of Ed s book are the ABYC Basic Electricity course the ABYC Electrical Certification course and the ABYC Ma rine Systems Certification courses Additionally his book is a resource for all boaters and want to be boaters who want to take ABYC boater courses seminars and workshops Visit www abyc com to learn more about the ABYC its mission and its ed ucati
139. ak in the circuit or an open circuit If your meter is reading a string of zeros perfect continuity is indicated with no perceptible resistance Any numbers shown on your meter including zeros show the resistance in ohms and indicate a complete circuit eR Fig 3 17 OL overload shown on the face of a digital mul timeter Specific resistance is not too important for gen eral circuit checks Specifications are never given and general assumptions really can t be made considering the variety of equipment available For example if you checked for continuity through a circuit for your stern light and you got a resistance reading it would indicate that all is well through the circuit The resis tance you re reading is in the light bulb filament Typically bulbs of this type will show several hun dred ohms of resistance But suppose you check the same circuit and you see an OL reading on your me ter This indicates an open circuit and most probably the bulb is blown and needs replacement An ohm reading near zero would indicate a short circuit between the positive conductor and ground If this circuit has been blowing fuses or tripping the cir cuit breaker you ll know you re on to something the first step in tracing a short circuit Figures 3 18 3 19 and 3 20 show the three possi ble meter readings and what is happening in the cir cuit to give these readings On some components like ignition coils and spark
140. akers had and the magnetic field they generated was sending my compass haywire Zone of Magnetic Separation The bottom line here is quite simple You must maintain a zone of separation between your compass and any new electronic gear you install The prob lem I had with my compass was caused by the new radio being too close to it Ideally in my experience a separation of about 16 inches does the trick but with highly magnetic equipment such as powerful speakers or radar that zone of separation can con ceivably extend to 3 feet or more You might be thinking that with your boat a 16 inch zone of separation is impossible your con sole just doesn t allow that kind of room Well that s OK a simple test is all that s needed to deter mine if you can close the zone Temporarily power up the equipment and move it near the compass while looking for any deviation in the compass dial By slowly and carefully moving the activated equip ment closer to the compass you can establish the actual minimum zone of separation for that partic ular piece of gear Keep in mind that in some cases any device such as one with a magnetic speaker can have a profound effect on compass deviation with out even being switched on In my experience Loran and GPS receivers have virtually no effect on compasses LCD fish finders also seem to be fairly harmless in close proximity to compasses However their CRT brothers can emit Installing Marine Electron
141. aking soda though If it leaks through the caps or vent holes into a cell it will neutralize the acid in the cell and destroy it Check cables and connections for integrity and tightness At any sign of corrosion remove the ca bles and use a wire brush or dedicated terminal cleaner brush to clean the post and the cable connector Terminal cleaning is shown in figures 5 6 and 5 7 Don t cheat and think that you have done anything constructive by cleaning the exte rior of the cable end terminal and post The elec trical contact is made on the inside of the terminal that s what counts If your battery has stud type terminals as many marine batteries do the cleaning tool will have to be helped a little with coarse sandpaper or with a wire brush or pocketknife The socket on the terminal tool just isn t deep enough to clean the entire length of a studded terminal Top up the battery with distilled water If you can t get distilled water at least use low mineral tap water There is a considerable variation in the mineral content of tap water from one municipal ity to the next Some tap water with low mineral Figs 5 6 5 7 Steps to cleaning the battery post and clamp using a battery service brush Use these tools until you see shiny surfaces on both the post and inside the clamp Figure 5 6 shows the terminal being cleaned figure 5 7 shows the battery post being cleaned 15 76 POWERBOATER S GUIDE TO ELECTRICA
142. all the connections Shore Power Branch Circuit Power Inlet Electrically Breaker Typical insulated from the boat i Cable Connector if isolator is installed ONAC and the wiring are intact Transfer Switch Grounding between your AC panel ea GEN OFF SHORE Type Receptacle the e did Shore Power Vo bisonnec OX an open indicates e1 Cable ircuit Breaker ther a break in continuity N aK inside the galvanic isola in ES aes tor ora problem onthe f EE i wos dock Have the marina ifc ams 7 2 operator verify the con 8 lt er d L3 g dition on the dock If it s 8 y J l Ji OK you may have a 3 2 d Opfidnal faulty galvanic isolator VII E 2 Pole 3 Wire rudes Any ABYC certified elec 9 8 Goggo a ee trical technician can 9 28g Receptacles Lio Main aout check this for you ifyou s 3 53 veo n 5 3 HE ficta eor Figure 11 24 shows 6 e the correct location for the galvanic isolator in 120 VAC Generator relation to your shore power inlet and the AC panel on your boat If Fig 11 24 Diagram of the galvanic isolator between the shore inlet and the AC distribution panel The galvanic isolator must always be the first device installed in series with the green wire as it enters your boat ABYC 179 Chapter 12 Installing Marine Electronic Equipment Electronic Gadgetry Some
143. allation of the CD player and speakers Remember that when locating the speakers the magnets contained within them will af fect things like compasses and any electronic com pass sensors you may have on board Keep the speakers at least 16 18 inches away from compasses and sensors 145 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS 1 Use the cutout template supplied with the 5 Test the operation of the equipment In other player and speakers to cut out your mount words turn it on and see if it works ing holes 6 Finish mounting the equipment chassis in the 2 Install your speakers and the player in the mounting hole Enjoy holes Figure 9 10 provides a wiring diagram for this in stallation that includes the speaker wiring If you keep the points mentioned here in mind for all of your DC circuit additions and carefully fol low the steps outlined including the tables and charts in chapter 4 you should have no problem adding 4 Connect all wires to the back of the player and your own equipment to your boat in a safe and pro to the speakers carefully following the printed fessional manner instructions supplied with the equipment as to which wire goes where 3 Route all wiring from power sources ground connections and any speaker or antenna leads Be sure to secure the wiring and pro vide chafe protection where needed as de scribed in chapter 4 Fig 9 10 Basic wiring diagram for a new CD player
144. ally de crease Several years ago when I was testing solar pan els for Cruising World I discovered that at noon on a July day at 42 latitude the panels were being heated to 120 F at which point their output began to dimin ish So when mounting panels on flat surfaces you must raise them above the surface to allow air to cir culate on both sides of the panels Since a solar panel will allow a battery to discharge through the panel when the panel is not exposed to the sun all panels must have a blocking diode in the posi tive feed from the charger to the battery The diode lets current flow from the panel to the battery but blocks current flow from the battery back through the panel On most panels the diode is in a small box mounted at the output terminals on the back of the panel Finally no panel should be installed without a charge controller a fancy term for a voltage regula tor since the 15 to 20 volts a solar panel can produce is too much for sealed gel cell or AGM batteries Some charge controllers have internal blocking diodes however and you don t want redundant blocking diodes since in marginal light situations the panel out put could be reduced to a useless value remember diodes have an inherent 0 7 voltage drop through them You can bypass or eliminate the blocking diode on the panel if the charge controller has an internal blocking diode Chapter 7 Maintaining Marine Ignition Systems Ignition System C
145. ame as the marine grade parts they are not The USCG mandates that ignition protection re quirements be met in the Code of Federal Regula tions CFR so this is not a mere recommendation but law The bottom line on ignition service is that no shortcuts are allowed Follow the advice in this chapter and you ll be way ahead of the game Outhoard and PWC Ignition Systems Unlike those on inboard engines most outboard and PWC ignition systems don t use battery power to feed the primary side of the ignition circuit With these systems voltage required for the primary side of the circuit is generated under the engine s fly wheel using the same principle of magnetic induc 103 104 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS tion already discussed in chapters 3 and 6 The essen tial difference is that these systems use a series of per manent magnets located around the inside perimeter of the underside of the flywheel As the engine rotates these magnets move past carefully placed coils of wire mounted on a timing plate which is also located under the flywheel You guessed it voltage is produced by induction in these coils One coil acts to produce the primary voltage which initially is much greater than with inboard sys tems Typical primary voltage is around 175 to 300 volts alternating current The coil producing this voltage is generally known as the charge coil and it sends its current directly to the system s igniti
146. ance with the very latest of the ABYC s electrical standards and the procedures described herein have all been tried and tested many times over by me per sonally and by my students Many of the tests and procedures that I have detailed here are identical to those used in my curriculum for the ABYC s elec trical technician certification program By following the recommendations in this guide you will be taking a long step toward keeping your boat s electrical system in top working order Then in those rare instances when a failure does occur the procedures outlined here will get you to the source of the problem quickly and easily so that you can effect repairs and be back underway without the stress and frustration normally associated with elec trical problems There are several points in this book where I clearly state that a professional marine electrician should be called in or consulted for certain com plicated difficult or dangerous operations Some of these procedures require either specialized equip ment or expertise and often both that goes far be yond the scope of this book Please do not take these warnings lightly or fail to heed them Expen sive and delicate electronic equipment can be dam aged and even destroyed by improper installation and repair techniques and the high voltage AC sys tem on your boat can be extremely dangerous if proper procedures are not understood and followed to the letter Household AC curren
147. and say a short prayer that I had set the dials and con nected the probes properly Any mistakes and the meter would make a little crackling sound emit a puff of white smoke and I would be holding a hand ful of useless junk This is a bit of an exaggeration of course but the point is that the multimeters of just a few years ago were unwieldy expensive delicate and hard to read and interpret That expensive analog monster I used in my early days as an electrician was not nearly as versatile and accurate as the most inexpensive digi tal meter is today What a difference a few years makes Huge 25 advances in multimeter technology and design have brought us meters that are compact the smallest is about the same size as and only slightly thicker than a credit card rugged reliable and so easy to read that a novice can be using one with only a few min utes of study They are also cheaper than they used to be now a perfectly usable meter with somewhat limited capabilities can be had for less than 20 at any Radio Shack about two thirds what an inex pensive meter cost 20 years ago Back when I bought my first multimeter there were perhaps a dozen dif ferent models from which to choose today there are hundreds of different makes and models available to the beginning electrician In fact there are so many different multimeters on the market that selecting the right one can be a bit daunting and if you make the wrong choice i
148. and am testing its function with a multimeter set to check continuity when the switch is tilted manually I m ver ifying with the meter that the switch turns off and on any spark Or you might have a strong spark and an engine that backfires when you try to start it or one that misfires at high speed Your ignition system could still be the culprit Before blaming the CDI unit or ignition control module for a no spark condition or bad timing the backfiring there are several addi tional things to check First be absolutely certain that all wires are hooked up correctly It s all too easy to cross plug wires or switch primary feed wires going to the high tension coils so that the CDI unit sends its sig nal to the wrong coil Double check everything against your engine wiring diagram Gang plug connections are always keyed so they only go to gether one way but it s easy to make a mistake on engines with individual terminals To avoid the pos sibility of crossfire between cylinders make sure that all high tension leads go into the proper hold down clamp on the engine Maintaining Marine Ignition Systems Loose Flywheel Check Next consider the flywheel Remember that it has carefully positioned magnets attached inside The fly wheel is keyed to the crankshaft so that these magnets pass the appropriate charge or trigger coil at a specific point in the engine s rotation On rare occasions usually after the flywheel has been r
149. and is also sometimes connected into a lightning protection system as well This wiring which is generally covered with green insulation and connects to things like seacocks and propeller shaft struts should never be used as a DC ground return for an electrical appliance GLOSSARY deep cycle battery A battery designed to withstand being deeply discharged at a moderate rate of current draw over an extended period de rating Reduction of a nominal rating typically used with ampacity and voltage drop tables Deutsch plug Trade name for a high quality wa terproof plug assembly DGPS Differential global positioning system using both satellite and land transmitted data to calcu late position dielectric An insulating material diode An electrical semiconductor that allows electrical flow through it in only one direction direct current DC Electrical current that flows in one direction See also alternating current AC double pole A classification of switch or circuit breaker that allows for the opening of two sepa rate connections simultaneously dry cell battery A battery using a dry paste like electrolyte instead of a liquid See also wet cell battery DVOM Common acronym for digital volt ohm meter also known as a multimeter or VOM earth ground A point that is at the same voltage potential as the local earth electrical potential Voltage electrolyte The solution inside a battery but can be any electrical
150. and then heat up to a point where it melts opening the circuit it s designed to protect The trick is to select a fuse that will allow sufficient amperage to flow freely through the circuit to run all the equipment on the circuit but will self destruct just before the current reaches the point where it can AVAILABLE INSULATION TEMPERATURE RATING 75 C 167 F 60 C 140 F 75 C 167 F 90 C 194 F 90 C 194 F 105 C 221 F See UL 1426 NOTE Some of the listed types are not commonly available in stranded construction for sizes smaller than 8 AWG Fig 4 6 Table IX from section E 11 showing insulation markings for typical wiring conductors found on board exclusive of flexible cables ABYC 47 48 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Conductor Size English Metric see Table VIII e UA N 10 1 40 165 9 ONCE 00 62 225 t2 Ww td t2 SiN w jN t2 t2 Ue 1 Outside engine spaces OS 2Inside engine spaces IS ALLOWABLE AMPERAGE OF CONDUCTORS FOR SYSTEMS UNDER 50 VOLTS Temperature Rating of Conductor Insulation 60 C 75 C 80 C 140 F 167 F 176 F OS I 5 OS I OS IS5 OS IS OS IS OS IS OS OR IS ie ow x s o 75 as uz real 5 us 5 23 35 3 0 3 pue 9 iso 25 15 so one as 38 ao 356 45 Fas 9 o m2 o 3 s 390
151. anufac Panel Switch Battery Bilge Pump Fig 9 5 Basic circuit components Fig 9 7 Wiring diagram for a bilge pump 143 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS not all are of the centrifugal type and correct im peller rotation is imperative if the pump is to work properly Adding a New Compact Disc Player A new CD player like any other electronic equip ment you decide to install or add to your boat s inventory of goodies is a prime example of equip ment that is polarity sensitive Essentially motors and any equipment that contains any type of solid state circuitry all fall into this category It pays to be quite cautious here as mixing the positive and negative conductors can burn out internal compo nents of valuable equipment quicker than you can snap your fingers Having said that the rest of the installation of a CD player is relatively easy especially if you have found the above descriptions of the installation of the cabin light and bilge pump easy to understand Really the most difficult part of installing a CD player is figuring out where you want to mount it and cutting the hole in the panel for the face plate Some electronic equipment today will have a heat sink mounted on the back chassis as shown in figure 9 8 This heat sink does just what the name implies it ra diates heat away from the parts within the equipment it s designed to protect Make sure that the air
152. any other things that can cause a spark plug not to fire An oil blend that s too rich too much oil in the gas a weak spark to a given cylinder incorrect heat range spark plugs and fuel system problems are just a few If you have regularly serviced your engine worn out plugs should not be a consideration So what s left Look at the plugs and verify that they can actually fire Remove the plug using a ratchet and spark plug socket or use the plug wrench supplied in the tool kit for your engine and look it over The plug should not be soaked with black fuel oil mixture Are the center and ground electrodes intact If not throw away the plugs and put in a new set 113 114 If the plug s center and ground electrode are OK and the plug is gapped correctly check the number on the plug and match it to the manufacturer s rec ommendations It may be the wrong heat range for the engine If all of these things check out OK insert the plug into the correct plug wire boot wedge the plug into a spot on the side of your engine as shown in figure 7 14 being sure that the metal case of the plug is grounded and crank the engine If you see a blue spark jumping from the center electrode to the edge of the plug on a surface gap plug or to the ground electrode on a standard plug the spark plug is OK and should fire in the cylinder If you don t see a spark or if you see a weak yel low one and you re sure that adequate cu
153. ards that dictate how designers and field personnel should carry out their work The basics of marine electrical system troubleshooting haven t changed much but certainly some of the equipment we install and use has This second edi tion ofthe Powerboater s Guide reflects these changes and provides an update to where we are in 2007 Ex amples of some of the new material found within this second edition include complete reference up dates to all the applicable ABYC electrical standards Since the first edition notable changes have been made to both the ABYC AC and DC standards in that what were once Standards E 8 and E 9 are now combined into Standard E 11 The ABYC battery standard has some significant changes within it and they are discussed here We ve also seen a major change in ABYC Standard A 28 Galvanic Isolators which now requires a status monitoring system to be integral with the isolator that information has been added to this edition Additionally and not standards based we ve seen some major improvements in both battery technology and battery combiner systems Compo nents that used to rely on either fully mechanical or electromechanical control have gone completely solid state and have added intelligence built in to provide much more accurate control of multiple battery systems New information is provided here about this new era of battery control In the area of engine specific electrical systems we ve moved from tradit
154. argers and the rules go like this Each ungrounded DC positive conductor connected to a battery charger alterna tor or other charging source shall be provided with tors as long as the connection is not at the battery the conductor is in a sheath and the wire is no more than 40 inches long The protection rating must be based on the maximum rated output of the alternator Figures 4 17 4 18 and 4 19 on page 58 illustrate the various allowable protection loca tions and the exceptions The above recommendations are intended to minimize the chance of an electrical fire on your boat But following these recommendations won t do anything to protect the equipment itself That s why many electrical appliances will also have a built in fuse However just because the device has a fuse built in doesn t mean you can wire it into your boat with out supplying an additional fuse or circuit breaker as close to the battery as you can get it Wire Routing and Support The wire routing and support standards of the ABYC are intended to keep electrical wires from getting burned chafed or soaked by bilge water It s impor tant to think dynamically when installing any new wiring or repairing old wiring Conditions change dramatically when your boat is underway in a rough sea with engine parts spinning away and exhaust at full temperature Improperly routed wires and bun dles of wire collected into harnesses can be damaged by spinning pulleys a
155. arging sys tem problem probably with your voltage regulator To solve this problem follow the procedures out lined in chapter 6 Figure 10 5 on page 153 shows the voltage and ground verification checks being made at the back of a typical voltmeter Temperature Fuel and Oil Pressure Gauges Engine service manuals generally combine these en gine instruments into one group for diagnostic pur poses because they all operate on the same basic principle they all use a variable resistance to ground to generate the instrument reading Figure 10 6 on page 153 shows a simplified wiring diagram that il lustrates how these gauges work Temperature Gauges Like all other gauges except the mechanical ones the temperature gauge needs battery power and a good ground to function If the gauge stops func tioning a simple way to verify that the electrical cir cuits are in order is to disconnect the wire at the sending unit the variable resistor on the engine and short the wire to ground with your ignition switch on If the needle moves all the way to the right to maximum temperature the problem with the cir cuit is a faulty sending unit which should be re Engine Instrumentation Problems and Solutions Fig 10 5 Verifying voltage and good ground at the volt meter placed If there is no change in the position of the needle trace the power to the instrument and verify the continuity of the ground l
156. art chargers are small reliable and highly efficient They are also extremely complex as compared to the simple ferro resonant chargers and I won t even begin to describe their circuitry Suffice it to say that they charge your batteries in precise steps or phases that are highly beneficial to the longevity of your batteries More important these steps are adjustable to accommodate the type of battery you have mak ing them the only choice if you have gel cell or AGM batteries These new smart chargers are produced by a number of manufacturers and have really gone a long way toward maximizing the potential for the newest battery technologies both gelled and AGMs How ever don t for a minute assume that a smart charger will be a waste of money if you have standard wet cell batteries All batteries will benefit from using a smart charger These chargers are available in a variety of configurations for single dual and three battery bank installations and have amperage ranges from Battery Charging Systems LU 20 30 jud AN AMPERES aF Fig 6 12 A ferro resonant charger These constant rate chargers have destroyed many a battery as few as 8 amps to as many as 130 amps for the largest inverter charger combinations Phases of Battery Charging Unlike the ferro resonant chargers that gradually re duce the charge rate along a rather steadily sloping curve as a battery comes up to charge smart charg ers use t
157. ary isolation of house loads from the engine circuit during engine cranking to protect sensitive electronics So there is no more blinking out of electronic gear during engine start ing when the whole system used to experience so much voltage drop that many electronic devices couldn t function normally Testing Your Batteries Even with proper maintenance all batteries wear out eventually The trick is to know when replacement is re ally required In my 35 years of experience dealing with storage batteries I d say that they are the most frequently misdiagnosed component in any electrical system Peo ple assume that because their engine is turning over more slowly than usual the battery is at fault and it needs replacement More often than not the battery is not the culprit but rather a loose or poor connection or perhaps a fault with the charging system Before you can make any real determination of the condition of your battery or begin any other serious testing you must first test your battery You need to recharge your battery first then check the battery s load handling capability Hydrometer Test So what are these tests and what do they mean Let s start with the hydrometer test Hydrometers are used to measure the specific gravity the ratio of one liquid density against another You re likely to encounter two and possibly three types of hydrometers used to check battery electrolyte condition antifreeze strength and di
158. as described earlier Follow the instructions printed on the tester to determine what course of action is required Fig ure 6 9 shows the LED tester connected and ready to check a charging system If you re not sure which terminal is B on your alternator refer to figure 6 1 If you don t have the tester you can do an alter nating current ripple test using your multimeter as shown in figure 6 10 Connect your meter leads to the battery with the red probe to the positive post and the black probe to the negative post and set it to the AC volt scale Run the engine up to a fast idle switch the meter to the alternating current volt scale and check the reading You should have no more than 0 250 volt AC at the battery If the reading you get is greater than that the diodes in your alternator are de fective and the alternator must be serviced Draw Test The last test I will mention is the draw test Particu larly in the marine environment it s possible to get electrical crossovers from a hot wire to a nearby ground causing a voltage leak that can drain your battery Testing for crossover current is fairly sim ple but a few precautions need to be mentioned You re looking for a constant electrical draw on your battery Make sure all the electrical accessories on your boat are turned off and the engine is not run ning Make sure you have disconnected everything including any radios and stereos with memories and clocks that byp
159. as wet cells and the materials are basically the same The big differences are that the electrolyte is rendered into a paste about the consistency of grape jelly and the plates which have a slightly different composition to reduce gassing are suspended in this goo Since there is no liquid to top up there is no need for the familiar caps and the cells are for all practical pur poses sealed There are several important advantages to gel cell batteries You don t have to worry about spilling the electrolyte by tipping the case over for one thing In fact gel cells work just fine on their sides or even upside down They hold a charge much better than wet cells and can be left unattended for longer peri ods of time and of course you don t have to worry about topping up the electrolyte The disadvantages of gel cells besides the cost which we will go into below are that they cannot be overcharged without suffering permanent and often terminal damage Also because the electrolyte can t circulate between the plates the way it can in a wet cell battery gel cell plates must be kept thin enough to accept a charge in a reasonable length of time Generally over the last few years gel cells have de veloped quite a bad reputation for not living up to the claims made for them by manufacturers Moreover gel cells have charging needs that differ from both the AGM which we will discuss next and wet cell bat teries Traditional con
160. ass the switches Next disconnect the positive terminal at the battery Set your multimeter to read amps and connect it in series with the termi nal end of the battery cable and the positive post on the battery A reading of any significant amperage over 0 01 amp indicates something on board is draining your battery Now you must locate which circuit is the culprit If your boat has fuses isolate each circuit by remov ing the circuit fuses one at a time and checking to see if the amperage reading is eliminated or reduced If you have circuit breakers carefully turn off the breaker switches one at a time until the amperage reading disappears or decreases to practically noth ing Once you have located the circuit that s causing the battery to be discharged you should be able to troubleshoot the circuit just as I described above Outhoard Engine Charging Systems Outboard engine charging systems come in two vari eties with or without voltage regulators The unreg ulated systems have an alternator built into the top of the engine that puts out constant amperage of 5 or 6 amps or more on newer bigger engines any time the engine is running Regulated systems use a volt age regulator that s similar to the one we discussed above However there are enough important differ ences to warrant a closer look Unregulated Systems Smaller outboards from 6 to 10 horsepower usually do not have a voltage regulator The charging systems
161. at could easily cause an explosion or serious burns Also wearing jewelry when work ing around batteries is risky for the same obvious reasons When connecting or disconnecting battery termi nals always disconnect the negative terminal first and hook it up last This sequence minimizes the chance that a spark can jump the gap between the battery post and the cable end terminal as you hook it up Don t smoke If you must smoke don t do it around batteries Batteries are heavy Use the carrying handles pro vided on good marine batteries and get help if you need it If your battery doesn t have carrying han dles borrow a special battery carrying strap as shown in figure 5 3 and use it Don t overfill wet cell batteries The excess elec trolyte will boil out as the battery charges leaving an acid film all over the battery and everything in the surrounding area Figure 5 4 shows the proper level to which each cell should be filled When the level is correct and you look down into the cell you should see a fish eye staring back at you Never attempt to recharge a frozen battery it will probably explode A frozen battery must be com pletely thawed before any attempt is made to re store it Odds are that it s dead anyway Never attempt to charge a battery that has elec trolyte levels that are below the top of the battery plates On sealed batteries with a charge indicating eye various colors are used to indicate the
162. at must be followed Be familiar with these steps and make sure you take them before you head off into the sunset The equipment avail able today is good but it s not completely magical it needs user intervention to give the best results by installing a factory sup plied harness which is avail able in different lengths One last thing regarding the radar antenna All closed array scanners those with a fiberglass enclosure come May have a with a condensation drain BEL valve on the bottom shell of ground the antenna housing Make sure this drain is unob T structed and working as it should at all times Conden sation buildup inside the an tenna housing will destroy the expensive circuitry in there Once the antenna is Scanner Fixed length cable mounted and the lead is fed Fig 12 16 Typical wiring hookup for a radar system Glossary ABYC American Boat amp Yacht Council Inc The preeminent standard making organization for the recreational boating industry The ABYC s Standards and Technical Information Reports for Small Craft covers all areas of small boat con struction and repair not just electrical matters alternating current AC Current that reverses di rection In the United States the current reverses direction at the rate of 60 times per second at 60 cycles or 60 Hz In Europe and other parts of the world the standard is 50 Hz See also direct cur rent DC fre
163. ates all of the dimensions outlined here One additional consideration besides the orien tation of the transducer is the wiring harness con necting the transducer to the display unit Even though these cables are generally much longer than needed for a typical installation the cable length should not be altered in any way Factory supplied extensions are available if more length is needed If stud with a wingnut on it at the back of the instrument This is the grounding lug Transducer Mounting and Troubleshooting Regardless of which brand of fish finder you have you ll have three choices for transducer mounting But if you wish to have the water temperature monitoring capability that comes with most top brands available today you ll be limited to two of the three mounting options No matter which mounting method you decide to use you must give your transducer a clear view below the boat that will not be clouded while underway by air bubbles or momentary separation 3 6 Skeg of the hull from the water For power Fig 12 9 Transducer location with separation zones measured out Lifting Strake 188 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS you find you have excess after running the cable to your display do not cut it and splice the connector to the shortened harness The length of this harness is engineered to a precise resistance and alteration will affect the performance of th
164. attery or any 12 volt battery with a set of automotive jumper cables Hook the positive lead to the battery first and the negative lead next Be careful not to let the clamps at the other end of the cables touch and arc Next set up your multimeter to measure DC amps When you re uncertain of the amount of current a piece of equipment will require it s best to perform this check with your meter s 10 or 20 amp setup An over reading on the wrong scale with the meter s leads in the incorrect sockets will blow the meter s Wire and Circuit Protection Standards and Repair Procedures internal fuse Make sure that the jumper leads are connected to the DC positive and negative terminals on the piece of equipment in question Clip the leads in series with the load and take the amperage read ing once the equipment is running With an induc tive clamp meter simply get the equipment running clamp onto either of the leads of the jumper cables and take a reading Figure 4 2 shows the hookup for making this ba sic test For a look at the typical amperage for com mon items of equipment you might find on your ULLLTTTT LELT u AA s Fig 4 2 Battery jumper cables being used to determine amperage draw for a new electrical installation In this case I m checking the actual draw for a new bilge blower boat refer to figure 3 15 on page 37 Once you have established the amperage for the equipment you re testing
165. basic multimeter require that the meter be connected in Fig 3 8 Meter lead connections on a meter and voltage checks for three light socket types Selecting and Using a Multimeter Figs 3 9 3 10 3 11 3 12 Various hookups for checking voltage drop In figure 3 12 the meter leads are shown as you would trace through a circuit looking for voltage drop at various points in the circuit Starter Motor Fig 3 9 Measuring the actual voltage Fig 3 10 Checking the voltage drop at Fig 3 11 Checking the integrity of the drop between the stud and the termi the switch Again the circuit must be starter solenoid Excessive voltage drop nal Remember the circuit must be on If the connections were clean and here necessitates removing the starter turned on to get any reading The tight the 0 2 V reading shown would in to replace the solenoid 0 2 V reading indicates either a loose dicate a fault probably corrosion inside or corroded connection that requires the switch repair Although less than 396 of 12V 0 2 V at any point in a circuit spells trouble at that point Bayonet Circuit Protector Switch On Fig 3 12 The solid leads measure the voltage drop in the positive feed wire to the light The dotted leads check the negative return A high meter reading indicates undersized wiring POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Q Switch On
166. been shortened from their original design Shorts as they are commonly called are almost always induced by human error and come in three varieties Shorts to Ground The first of the three is the short circuit to ground With this condition the wire to the electrical load 10 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS the feed has somehow connected itself directly to ground before reaching the appliance In a short to ground the resistance in the circuit which you ll re member is essential for a circuit to operate has been circumvented As Ohm s law will tell you if you work through the numbers a lot of amperage will flow with only the resistance of the wire to stop it The good news If the circuit is designed correctly the fuse or circuit breaker will trip The bad news Some wire and insulation may be burned before the cir cuit protection opens the circuit Intercircuit Shorts The second variety of short is what I refer to as the in tercircuit short With this type two or more electrical circuits will be affected simultaneously The cause Drilling through a wiring harness to install new deck gear and then running a screw down through the deck into the harness effectively connecting multiple circuit wires This short circuit with a screw is quite common Another frequent cause for this type of short is not thinking dynamically Remember our electrical system will change when the engine is run ning and while we are u
167. before mounting it close to your compass Once you decide where to put your fish finder or depth sounder make a DC positive and negative con nection for powering it The best bet is to hook it up to a dedicated bus bar Refer to figure 12 3 on page 183 to refresh your memory on how this is done Don t forget that depending on the manufacturer you may need an additional grounding lead to the unit s case Be sure to check your installation manual to determine this Note An easy way to figure this out is to look for a threaded Installing Marine Electronic Equipment boats the transducer should end up toward the rear of the boat at a point on the hull where the bottom is submerged at all speeds and under all normal sea conditions You should also consider the noise the air bubbles and turbulence generated by propellers and lifting strakes built into the hull This interfer ence can reduce transducer performance As a general rule try to mount the transducer at least 18 inches about 46 cm away from the pro peller The face of the transducer should also be in ward of the first lifting strake on the bottom of the hull by about 3 to 6 inches 7 6 to 15 cm If your boat has a skeg or keel mount the transducer about 12 inches 30 cm to the side of the keel This is not to minimize the effect of turbulence but to ensure that the transducer s conical beam is not partially blocked by the keel reducing its performance Figure 12 9 illustr
168. both To simplify all this spend the extra money and buy the inverter manufacturer s optional system monitor You can cover all the compliance issues in one shot and get some features built into the dedicated system moni tor that are extremely worthwhile These monitors can provide important data such as volts amps amp hours consumed and time remaining on the supplying battery bank to name just a few of the avail able functions Figure 11 21 on page 175 shows a typ ical inverter monitoring system This one is a Link unit from Heart Interface now part of Xantrex circuit protection and system monitoring As for overcurrent protec tion consider that both the AC and DC sides of the in verter will need some form of overcurrent protection in stalled The output side of the inverter may have a circuit breaker built in but it pays to double check As for the DC side protection will need to be installed The special fuses slow blow used for this purpose are generally not provided as Fig 11 20 A T type fuse installed in an inverter DC feed cable Alternating Current and AC Equipment AC Generators Just as with inverters advanced trou bleshooting and installation procedures for AC generators go way beyond the scope of this book These things are best left to the ABYC certified professional marine electri cian However some general knowledge of these workhorses is still important for
169. bsystem the console navigation subsystem the lighting sub system and the house or utilities subsystem Another way to do the same thing is to divide your boat phys ically with each division labeled as a subsystem so that the head galley forepeak engine compartment and anything else that s appropriate for your boat be comes a subsystem The actual division will depend on the size and the kind of boat you have but you get the idea Next get three or four large 11 by 14 inch is ideal sheets of graph paper for each of your sub systems you ll be doing each one over several times and a large clipboard or a piece of plywood to write on Write the name of each subsystem on a separate sheet of the paper The Rough Draft For your first draft you re going to make a separate diagram for each subsystem You ll put them back to gether for the final if you like but for now it s a lot easier to keep the systems in order if you keep them separate in your mind s eye hence the separate sheets of paper As a logical first step let s start with the charging and starting circuit it s one of the simplest but also one of the most important First draw a sketch of the battery symbol as it s shown in figure 2 1 on page 13 for each of the bat teries on your boat Now label each battery with all the pertinent information you have available This might include the cold cranking amps and the amp hours if you know these things much
170. camshaft to sense piston position in the cylinders High tension coils to supply secondary level high voltage to the spark plugs A DIS may have one coil per cylinder or one coil for a pair of cylinders On paired systems each end of the secondary windings of the ignition coil will be con nected to a spark plug as shown in Figure 7 1b These ends are connected to cylinders that are opposite in the engine s firing order but both at top dead center TDC simultaneously One plug will fire on the com pression stroke and the other will fire simultaneously on the opposing cylinder s exhaust stroke referred to Ignition Module Magnetic Triggering Device O OOO O Coils T UL HP a L MN La aic EL DOU alll T OC EIE Fig 7 1b A paired cylinder DIS as wasted spark It doesn t really hurt anything but it reduces the number of components required Employ the basic maintenance considerations as for any ignition system Keep coil towers and plug wires clean and free from any oily film that can attract dust and then moisture droplets which will ultimately cause high voltage arcing and insulation damage on the wiring and coil cases If a problem does occur with one of the electronic components specialized scan tools are required to properly diagnose computer and ignition modules To date I ve only had to replace the spark plug wires about every 750 to 1 000 hours
171. cate a relative component location on the boat but don t count on it usually you have to search on your own to find all the components in a given circuit small batteries 800 CCAs is more than enough current to start a fire and cause serious burns in the event of a short Thus a means of quickly disconnecting these small batteries is no less important than it is for the big guys in my mind All batteries regardless of CCA rat ing should have a master shut off switch Chasing Circuits Remember that the distribution panel or panels sometimes there are more than one on your boat is the point at which most of the circuits on your boat come together in close proximity and the situation 19 20 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Panel Board Feeder Wire Circuit Protector P Battery Master Switch Fig 2 7 A proper power supply circuit to the switch panel showing the circuit protector fuse or breaker and the bat tery master switch always looks a lot worse than it really is Once you learn what a basic circuit looks like and develop the habit of ignoring everything but that one circuit you re working on all that spaghetti will start to make sense and everyday repairs will come easily and quickly For example suppose one Sunday morning you decide to take the old Donzi for a run out to Block Is land to buy the kids and some friends a pizza It s a beautiful sunny day with a fla
172. ched Depending on which depth sounder or fish finder you have you might hear an alarm indi cating high or low voltage or the unit may automat ically shut down There is no problem with the unit itself but it s a problem nonetheless The other fairly common problem with these units is fouling of the face of the transducer with sea growth Barnacles and other marine growth will eventually block the face of the transducer and affect its ability to transmit and receive a signal The solu Transducer Fig 12 12 A transom mounted transducer 189 190 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS tion here is simple Either periodically wipe down the face of the transducer with a wet cloth to clear the surface or prevent the fouling in the first place by using transducer antifouling paint available at West Marine and other marine supply houses I don t recommend that conventional bottom paint be used to protect these surfaces If your fish finder or depth sounder stops work ing altogether or begins to send mysterious signals through your display there are several additional steps you can take to isolate the problem First en sure that the display unit is get ting power and has a good Installing a GPS Receiver Whether you re installing a conventional GPS receiver or a chart plotter with an integrated GPS sensor you essentially need to make the same considerations as you would with all other electronic
173. cing inside the ventilation ports of the alternator Other differences between alterna tors for cars and those for are offset look for an arrow stamped on one of the blades that will show the direction of rotation and always check the manufacturer s literature for exact installation instructions Alternator Electrical Connections The best bet for identifying the wires connected to your alternator is to use your engine s workshop manual and wiring diagram If after testing your al ternator you discover that it must be removed for overhaul or replacement carefully mark all the wires with tape Also mark the terminal identification on boats are that marine alter nators are of heavier con struction may have a higher output and have fewer cor rosive parts than those for cars do Don t let anyone talk you into substituting This is an area mandated by the USCG on gasoline pow ered vessels Those ventilation ports Early Prestolite Style Fits OMC Green or Yellow Field Aux Not Used B B Output Ground B mentioned above also testify Output eal aad to n alternator s need for Volvo Paris Rhone Fits cooling air That thing on the Volvo Penta Delco Self Exciting Style its MerCruiser pulley that looks like a fan is gt B f Output in fact a fan Often these fans B og Ground have blades that are set to work in one direction only S E D or 61 and the direction of engine Indicat
174. coil is much longer than that in a trigger coil and therefore has a higher resistance The wiring harness for these coils is always se cured to the movable timing plate under your en gine s flywheel and usually exits from under this assembly on the starboard right side looking toward the bow of the boat of the engine power head Once you have located the harness and found all the wires that come through it match the color cod ing on the wires to your wiring diagram and deter Maintaining Marine Ignition Systems mine which wires go to and return from the charge and trigger coils These wires often terminate in a gang plug that con nects to the CDI unit Disconnect this To test the charge coil set your ohm meter to the scale for the expected resis tance as specified in your engine manual Insert the red and black test probes into the plug socket that matches the correct color wire and take a read ing Charge coils generally have resis tance between 400 and 900 ohms If the reading is more than that or if a reading of infinity indicates a break in the wiring the charge coil is defective and must be replaced EY plug to continue testing e e Next check for a short to ground by Fig 7 17 Continuity tests through the trigger coil test and the short to removing one of the meter probes from ground test Again you ll need your workshop manual to get the proper the plug assembly Now switch your me specificat
175. ct each individual piece of equipment If in the example above there were two other pieces of equipment sharing the cir cuit with our 5 amp device one drawing 1 amp and another drawing 2 amps you would have a total of 8 amps on the circuit You could then have the 10 amp main fuse or circuit breaker for the wiring and three individual fuses of 5 2 and 1 amp each to protect the equipment Panel Feed Wire An additional consideration especially if you re go ing to be adding heavier loads or multiple addi tional loads to your distribution panel is the size of the wire and the rating of any circuit breakers or fuses feeding the distribution panel Keep in mind that the builder may have based the size of the positive and ground wires to the panel only on the factory installed equipment even though the panel may have blank sockets where additional breakers and circuits could be added Distribution panel ratings are based on the sum of the ratings of all the circuit breakers installed on the panel The ampacity of the conductors feeding the panel must match that total amperage Thus a panel with two 20 amp breakers five 10 amp break ers and five 5 amp breakers not an uncommon arrangement would need a master circuit breaker or fuse and a feed wire that could handle 115 amps if everything on the boat were turned on at once The ABYC also says that if the panel has a master circuit breaker on the panel rated at no more than 100
176. cuit It s equally important with an AC circuit but it carries the added influence of induction the generation of an electrical current in a wire exposed to a magnetic field Induction becomes important with AC be cause of the higher voltages remember how the strength of a magnetic field increases with an in crease in voltage Also the tendency of resistance in a DC circuit to cause a buildup of heat which in turn causes an increase in resistance is not as important in an AC circuit the reversing electrons just don t get a chance to generate a lot of heat be fore it s time to turn around and go back to where they started This makes AC much more efficient than DC when higher voltages are needed and it s one of the big reasons we use it at all Copyright 2000 2007 by Edwin R Sherman Click here for terms of use Impedance Impedance is the combined effect of resistance and induction The place you ll hear the word used the most around boats is when working with your radio antennas see chapter 12 Voltage drop The efficiency of AC is also the rea son that voltage drop which I have repeatedly stressed as one of the most important considera tions in any DC circuit just isn t important in an AC circuit Also because of the higher voltages used in AC a much lower amperage is needed to do a given amount of work remember Ohm s law which further reduces the importance of re sistance and voltage drop
177. cuit breakers 2 50 51 AC 162 63 164 165 ampere interrupting capac ity 51 bimetallic 51 for DC accessories 137 38 engine mounted 91 GFCIs 166 67 locations for 55 57 magnetic 51 100 150 percent rule 54 55 56 removing 51 52 7 40 72 rule 57 58 standards for 46 51 testing 53 54 trip free 51 162 circuit identification 17 19 circuit problems 9 10 circuit protection in battery installations 57 58 100 150 percent rule 54 55 56 7 40 72 rule 57 standards 54 55 57 58 circuit protectors 2 circuits 1 5 See also alternating current AC circuits direct current DC circuits starter motor circuits chasing finding 19 20 components of 14 15 20 22 continuity resistance tests 39 identification of 17 19 marine 2 3 marine vs automotive 3 motor 54 55 nonmotor 55 parallel 2 4 problems 9 10 series 2 3 4 series parallel 2 4 5 voltage drop 8 9 tachometer 150 closed switch 2 coaxial coax cable 184 86 Code of Federal Regulations CFR 102 cold cranking amps CCA 19 71 72 color coding ABYC 15 17 for AC wiring 158 59 for DC accessories 138 ISO 159 reverse polarity 159 substituting wire colors 18 19 colored heat shrink tubing 18 19 colored tape and wire ties 18 compass deviation 180 81 191 conductors 2 allowable amperage of 46 48 161 163 bundling of AC 160 61 insulation and temperature ratings 46 47 48 161 162 163 sizes
178. d grasp of the basic principles of electricity will find some of the following to be repetitious but bear with me even those of us who work in marine electricity every day will benefit from a good review of the funda mentals Let s start with a brief discussion of the most basic of all electrical components the circuit Electrical Circuits Electrical circuits are just what they say they are circles or loops of conductive material that allow an electrical impulse to flow around and around in an endless orbit This conductive material is most often copper wire but it can actually be nearly any mater ial In an automobile the engine block and chassis are critical parts of many circuits At home the very earth your house is sitting on is a part of the electri cal circuit and is essential for the correct operation of your pop up toaster and your television set That s why one prong on all your electrical plugs is called the ground There are several types of electrical circuits with which we will want to become familiar However regardless of type the essential elements of a circuit will always be the same pm All circuits on a boat need a source of electrical power it could be a battery your municipal power through a shore power connection a gen erator an engine driven alternator a solar panel or a wind driven turbine It can even be with cat astrophic results the chemical reaction between your aluminum outdrive and
179. d of wiring diagram showing their exact location even then they can sometimes be hard to find Hidden junction boxes can often be the source of a loose or broken connection in a circuit and must be found before the faulty circuit can be put back into service The first thing you do once you find one of these lost junction boxes is to note its location on the wiring diagram for the future reference of the next poor slob who has to work on the boat I don t have any way of telling how much time I have wasted over the years emptying out lockers and pulling up floor boards trying to find one of these elusive connection points but I know that it s a lot Figure 2 9 shows one of these junctions carefully hidden Locating Wires Another common problem you will encounter as a beginning marine electrician is the mysterious case of the vanishing wires Often wires exit the distribution panel only to disappear behind a cosmetic bulkhead or cabinet Worse yet they vanish into a molded in conduit on the inside of the hull only to reappear at the component itself The wiring can travel the entire length of the boat without leaving a single clue as to what may be going on between the distribution panel and the light fixture or whatever other component is in question This is another case where a good wiring 21 22 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Fig 2 9 A wiring harness junction located inside a loc
180. d taking it to an alternator shop which has the special equip ment needed to make delicate repairs Some manu facturers have factory exchange programs that allow you to exchange your unit for an identical factory rebuilt replacement for a fee of course It s a simple matter to pop the old alternator out exchange it at the dealer s then pop the new one back in This ex change is sometimes available no matter what con dition your old alternator is in a real blessing when you experience an engine fire or after your alterna tor gets doused with salt water Many offshore boats carry a spare rebuilt alternator that can be substituted for a defective unit if it should give up the fight while fishing the Gulf Stream or on a long weekend in the Bahamas This swap and replace procedure presupposes that you re able to diagnose when and why the alter nator in your system is acting up 87 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Marine versus Automotive Alternators Before one of your dockmate electrical experts there s one in every marina tells you otherwise remember that there is a big difference between marine and automotive alternators The brushes are sealed on ignition protected marine alternators used on gasoline engines this prevents dangerous sparks that could cause an explosion If you want to see the difference just open the hood of the fam ily car in the dark while it s running You re likely to see sparks ar
181. d up to a maxi mum of 10 percent voltage drop for noncritical equipment In a perfect world and certainly in any electrical work you perform it s really best to shoot for 0 percent voltage drop as an ideal but in the real world some voltage drop will always be present es pecially in long wire runs There are several simple math problems that may help you to get a feel for what the ABYC maximum voltage drop figures mean Assume a 12 volt system If a noncritical circuit is allowed a 10 percent maximum voltage drop you need to know what 10 percent of the system voltage for your 12 volt circuit equals In practice the actual numbers will be slightly different A fully charged 12 volt battery will have a voltage of between 12 6 and 13 5 volts The actual voltage would change the fol lowing numbers slightly but we will use the 12 volt figure to simplify the math To find the allowable voltage drop turn the per centage into a decimal and multiply it by 12 the sys tem voltage in this example The problem looks like this 0 10 x 12 1 2 The maximum allowable voltage loss would be 1 2 volts so by subtracting 1 2 volts from the original 12 volts you end Battery Circuit Protector Cabin Light Cabin Light Cabin Light up with 10 8 volts as a minimum al lowable voltage at any point in the circuit Applying this same math to the 3 percent criteria multiplying 0 03 x 12 gives a maximum allowable voltage drop
182. d winding wrapped around it rpm Revolutions per minute scanner Moving radar antenna rotating self discharge The gradual loss of a battery s ca pacity as it sits in storage self limiting An electrical power source whose maximum output is restricted by its magnetic and electrical characteristics self scaling auto ranging ammeter A meter that automatically selects its best range for a measure ment series circuit A circuit having only one path for current to flow through series parallel circuit A circuit combining ele ments of both a series and parallel circuit sheath A material used as an insulating protective cover for electrical wiring shore power Power delivered from the dock short circuit A circuit fault that effectively short ens the designed path of current flow through a circuit Short circuits usually eliminate the load from the circuit allowing excessive current to flow shunt A short electrical bypass generally associ ated with an ammeter single loads An individual electrical load in a circuit as compared to multiple loads supplied by a circuit sine wave The waveform made when alternating current is charted over time slaverelay See solenoid slow blow MDL fuse A fuse with a delayed ac tion used in motor circuits and other circuits where start up load is significantly greater than the continuous current draw on the circuit smart charger charger Computerized multistage ba
183. de of the engine block This terminal will generally be much larger than the others If you find 12 volts at this plug and the plug terminals are in good condi tion it s reasonable to assume that 12 volts is getting to the remote control assembly and feeding the ig nition switch In all cases there will be a wire coming from the remote control assembly that provides 12 volts to the ignition module CDI unit on your engine This wire activates the electronic circuitry within the module while the engine is running Use your wiring diagram to identify this wire on your engine Make sure the emergency shutoff switch is off and turn on the ignition key A reading of 12 volts where this Fig 8 9a Checking voltage supply to an outboard engine solenoid with the key in the start position Remember with the key in the start position if the engine is cranking the voltage reading will drop down to as little as about 9 6 volts wire attaches to the ignition module tells you that this function of the ignition switch is OK If you don t get 12 volts here you need to trace the main harness and look for any trouble spots correct them as needed If no trouble spots are found the problem is in the remote control unit A possible trouble spot could be the point where you drilled a hole through the harness when you were mounting that new rod holder or downrigger In addition to 12 volts at the ignition module when the key is turned to start and
184. dels of engines are difficult to come by Manufacturers usually don t provide these data even in their workshop manu als As a means of estimating current requirements for starter motors mechanics have for years used 1 amp for each cubic inch of engine displacement as a starting point for gasoline engines Diesel engines operate with much higher compression ratios so a diesel starter motor might draw as much as 2 amps per cubic inch of displacement Both these values are only good for very rough estimates of starter motor current Gear reduction starter motors which have become increasingly popular in recent years typically draw much less current than do direct drive motors about half for a two to one reduction ratio Fig 8 5 Checking for voltage supply to a starter motor sole noid You should get a reading of approximate battery volt age here 127 128 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS So if the amperage specifications aren t available from the engine maker how do we get them Easy Just do a current draw test when you know your starter is working normally and record the amper age the starter motor uses in your manual Then when a problem does crop up you ll have a known value to work with as a benchmark To do the current draw test first make sure your starting battery is in good serviceable condition If you have an inductive clamp multimeter capable of measuring up to about 500 amps clamp the ind
185. discuss the details for each of these proce dures in a little more detail Testing Spark Plug Wires Testing spark plug wires is easy If you have already used the spark tester and seen a spark at the end of the spark plug wire you know the wire is conducting Fig 7 15 An ohmmeter test of a spark plug wire Depending on your engine type you may or may not measure resistance of any value when performing this test With resistor type wires used on some of the newest engines readings of 5 000 10 000 ohms for each foot of wire length are not un common Maintaining Marine Ignition Systems electricity to the plug But that s not all the wire has to do It also has to insulate this electricity under all engine operating conditions and conduct electricity when your boat is underway and the engine is vibrat ing Look at the wire and the wire ends inside the protective boots Look for any sign of cracking worn insulation and any sign of green corrosion on the metal clips that lock the ends of the wire to the coil and spark plug If you find corrosion slide the boot back onto the wire and carefully clean the connector with a wire brush until the metal is bright and shiny If the wire is chafed or cracked replace it To check the wire electrically set your multimeter on the low ohms scale and insert the meter probes into the wire as shown in figure 7 15 The meter should read near zero ohms except on some of the ne
186. dition replace the gasket A fuel leak here is ex tremely dangerous and cause for immediate concern If your tests of the fuel gauge sending unit cause no movement of the needle on the gauge verify that you have power and good ground at the instrument just as with the temperature gauge already described If this fails to locate the problem replace the gauge Oil Pressure Gauges Oil pressure gauges are tested in the exact same way as both the temperature and fuel gauges mentioned al ready Figure 10 9 on page 155 shows the location of a typical oil pressure sending unit on a General Motors V block used widely by MerCruiser OMC Volvo Penta and other marine engine manufacturers For the exact location of the sending unit on your engine refer to your engine workshop manual Trim Gauges As mentioned earlier trim gauges generally Fig 10 8 Fuel tank sender removed and being tested Move the float up and down while watching the ohmmeter Look for a progressive Finally if you have any real doubt about the change in resistance value Any OL readings while performing this accuracy of your gauges you should consult a test indicate a dead spot in the sender and it will need replacement professional with the mechanical and elec 154 found only on outboard and IO boats have an extremely high failure rate because the sending units on these boats are located un derwater on the engine drive unit These sending
187. e a mess and it can be difficult to reassemble If the remote control assembly has a key switch sep arate from the shift control this central pivot screw will not be a problem You can usually access the back of the switch without removing the switch from the panel Now use your wiring diagram to identify the wire coming from the back of the ignition switch to the ground shut off at the power pack As with the smaller engines this wire will usually terminate at a gang plug under the engine cowl in the harness going to the power pack Once you find it disconnect the plug or connection to the remote control assembly Now you re ready for your ohmmeter tests Check at the engine end first and for your multimeter s safety be sure your battery is disconnected before doing this test First connect the red probe on your ohmmeter to the wire that runs from the ignition switch to the re mote control assembly Connect the black probe to a good ground With the ignition key on you should get a high reading or infinity If your meter indicates a complete circuit with a resistance reading near zero 119 120 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS disconnect this wire from the back of the ignition switch and recheck the meter reading If the meter now reads infinity the ignition switch is faulty and must be replaced If the meter reading has little or no resistance it indicates a complete circuit to ground mean ing th
188. e and in sulation resistance of the insulation to oil moisture and fuels and temperature rat ings of the insulation are all explained in cryptic notation Again our friends at the ABYC come continued on page 46 43 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS CONDUCTORS SIZED FOR 3 PERCENT DROP IN VOLTAGE NOTE In the event of a conflict between the voltage drop table and the ampacity table use the larger wire size Length of Conductor from Source of Current to Device and Back to Source Feet 10 15 20 25 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 12 Volts 3 Drop Wire Sizes gauge Based n Minimum CM Area IN AMPS 5 10 15 20 25 30 40 50 60 70 80 90 100 eo o o TOTO ROOOC NNNAPROODD OOANNDAADAO WNOHANNAH OOS S oo TOTO R0 000 OOH s NMNHLEAADD 24 Volts 3 Drop Wire Sizes gauge Based on Minimum CM Area N 18 18 18 16 16 14 18 16 14 10 16 14 12 10 12 10 12 10 10 10 10 8 8 o o o e NOOQO NNLFSAOD CO NNFADHOS COHANNALOOS ROHANNAAMODS S COOH NNA DO a MNN SOOO O o Qmm sas Boom SSS 32 Volts 3 Drop Wire Sizes gauge MN 18 18 18 18 16 12 16 14 10 14 14 12 14 12 12 12 12 10 10 10 10 8 8 b e o ANNNNAAAAOMD O NNNADHHO CO NNAHRDHOO mmoo mnmnmoie oooo OCOOsANNALADDOOD OOANNALADAA OOH MNFADD VPHROCANNALELDOA oo DO NNA OD NN PARA OO NNNMNAAHOH O 8 6 6 6 6 8 8 6 6
189. e black probe to a negative terminal or wire or to ground your meter will tell you the voltage at the point the red probe is touching In other words whenever your meter leads are connected to the cir cuit in parallel as is explained in chapter 1 with some sort of load between them you get a voltage reading Inexperienced meter users often make simple mis takes and become puzzled when their new meter shows no reading at all This absence of a reading can be dangerous because it can lead the novice to believe the circuit is turned off when it s in fact still live or hot Figure 3 5 on page 32 illustrates a multimeter properly connected to a 12 volt circuit to check for ad equate voltage at a cabin light The red meter lead is connected to the positive terminal on the light and the black lead is connected to the negative connection Many beginners get confused when they try to check voltage at points throughout a circuit and can t figure out what to do with the black lead This lead should always be connected to the yellow or black on older boats lead of the circuit you re testing or to a good ground connection Figure 3 6 on page 33 shows this same circuit with a meter hooked up in parallel to the switch ac tivating the circuit In effect both meter leads are connected to a positive feed with no load between them This hookup is incorrect and will not show a voltage reading under any circumstances Testing for Voltage Drop
190. e cases protection for all of these areas can be provided by just one GFCI outlet with conven tional outlets installed downstream from the GFCI To protect the other outlets downstream the GFCI must be the first outlet in the circuit On larger boats this protection may be broken up into more than one circuit necessitating the use of several GFCI outlets Ignition Protection with GFCIs All of this is of particular significance to boats that use gasoline as fuel and must meet ignition protection re quirements as discussed in chapter 4 Most GFCI out lets are not rated for ignition protection and therefore should never be used in engine rooms Marine grade GFCIs are available but at considerable cost This is really no problem for either the boatbuilder or you if you intend to add an outlet in your boat s engine room Simply use a conventional outlet in the space requiring ignition protection and tie it into a GFCI outlet mounted in a safe area such as in the galley Figure 11 8 illustrates how this arrangement should be wired Testing GFCI Outlets All GFCI outlets used on boats must be tested monthly The delicate internal mechanism of a GFCI outlet used in the harsh marine environment can corrode and cause the unit to not trip when you need it most The simple test procedure is often over looked and not testing each outlet every month can cause obvious problems it won t work when it s re ally needed
191. e effective Once again our friends at the ABYC have pro vided some guidance In their view solder must not be used as the sole means of connecting terminals to wire The connection must first be mechanically fas tened crimped and then soldered They do make an exception however relating to battery terminals Battery terminals may use only solder as long as the cable enters the terminal at a minimum distance of 1 5 times the diameter of the conductor the battery cable itself This is shown in figure 4 22 The reasoning behind the ABYC s crimp plus sol der recommendation for connections may not be clear to the novice electrician Excessive current can generate enough heat in a poor quality connection to melt the solder allowing the terminal to come un done I recommend that you stick to crimping fol lowing the guidelines given here First select the correct terminal Figure 4 23 shows the preferred types all captive by definition Cap tive means that if the screw or nut holding them in place comes loose they won t fall off the shank of the screw or stud The figure also shows some types that should never be used Don t ever wrap the bared end of a wire without a properly attached terminal around a screw and tighten it in place With stranded wire the only type you should be using it s quite easy to have some of the strands squeeze out and they can end up touching an adjacent terminal causing a short circ
192. e nature of the lines what the roads would be like paved or dirt straight or twisty single lane double lane divided or interstate You would also see intersections junc tions detours and areas of potential trouble and con gestion To see what the various Working with Wiring Diagrams to figure out Before we do anything else let s take a look at a few of the more common electrical symbols that you re likely to encounter on any standard wiring diagram Common Symbols Like road maps wiring diagrams use a variety of symbols to indicate different components within an electrical circuit Electrical engineers are trained to recognize several thousand of these symbols and to understand just what they mean This gives wiring diagrams a certain consistency To the untrained eye however these symbols can be as cryptic as an an cient Chinese manuscript Figure 2 1 illustrates some of the symbols most frequently used in marine wiring diagrams Elements of a Good Wiring Diagram A wiring diagram should be laid out just like a road map and will incorporate many of the features of a symbols and graphics mean you 4 entrees Switch SPST would look at the key or legend i o o single pole Y Diode E b no connection single throw T rectifier which is usually provided on a cor ner or on the back of a map Conductors ae Switch SPDT E The wiring diagram you re go connected O Sane zd ouble throw ing to develop
193. e or black numbers 17 18 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS printed on them black for the white and light col ored wires and white for the black and dark colored wires To use them first identify the circuit you want to label by the nameplate on the front of the distribution panel adjacent to the switch or circuit breaker It will probably say something generic like accessories There are usually five or six labels of each number in a set so all you need do is place a number on the first wire behind the switch panel then trace the wire to the fixtures that it operates Place labels at strategic places along the wire as you go Next trace the yellow or black wire back to the common bus which should be located somewhere near the distribution panel and label it the same way Now write that circuit number down someplace handy and move to the next circuit If you already have a wiring diagram you should also write the new circuit number on the corresponding circuit on the diagram Now you know that the circuit on the switch panel marked accessories is circuit number 32 and it feeds the light in the forepeak and the exhaust fan in the head If either if these appliances should stop working all you need do is trace wire number 32 un til you find the problem Named Labels Several manufacturers make label sets that you can use just like the numbered labels They simply state just what fixture or fixtures a sp
194. e unit Coil excess wire neatly and lock it together with some tie wraps Hide the coil behind an out of the way panel away from any other electrical cables or harnesses It s possible for this cable to be affected by cross induction from other electrical cables and devices Remember all wires with electricity running through them have a magnetic field around them Cross inductance here will affect the sensitivity of your depth sounder or fish finder Inside the Hull Mount If you aren t using a transducer with a water temper ature probe built into it you may want to mount your transducer inside the hull This is the simplest of the installation choices and will generally prove satisfac tory but you may experience a loss of range If your boating keeps you in less than about 100 feet of wa ter this method may work well for you This ap proach only works on boats with a solid fiberglass bottom Cored bottoms will not precisely transfer the ultrasonic waves from the transducer and per formance may be greatly hindered If you re not sure if your boat bottom is cored check with the builder before moving ahead on this type of installation If you re determined to try for an in hull installa tion do some experimenting first Connect the trans ducer to the sounder s display and temporarily adhere the face of the transducer to the inside of the hull with some nonhardening adhesive such as BoatLIFE caulk or a similar polysulfide sealer
195. e values are dif ferent The total circuit current in amps will be the sum of the current drawn at each load in the circuit Circuit Problems and How They Occur In my years of listening to people talk about electric ity I ve learned one thing for sure To the uniniti ated every time anything goes wrong with their electrical system it s described as a short Although this is certainly possible the truth is that most prob lems that occur with electrical systems on boats are not short circuits In fact a more probable cause for electrical trouble on a boat is caused by the unwanted open or interrupted circuit already mentioned So what are the common problems and what are some of their causes and characteristics Open Circuits An open circuit is one that contains a break or open in the continuous path or route for electron flow described earlier This can be caused by a break in the wiring a connection that has come undone or cor rosion that accumulates to the point where the volt age drop is so great that current will no longer flow in the circuit By comparison a wanted open occurs when you switch off an electrical device The switch effectively breaks the continuity through the circuit To pinpoint unwanted opens in a circuit you must attack them systematically with your multimeter and we will learn just how to do this in a later chapter Short Circuits Short circuits are just that circuits that have
196. e wire that connects the igni tion switch to the engine is shorted to ground and must be re paired If all of these readings check out turn off the key switch Battery and check your meter You should a roun have a low resistance reading near Sable zero ohms If your meter still gives a reading of infinity check that the ground for the key switch is con nected and in good condition If it is you may have a break open circuit in the wire leading from the switch to the terminal on the engine Check the entire length of this wire for a break and either in stall a new wire or splice the break Starter motor Solenoid Engine ground Remote control with key switch and neutral safety switch Remote control harness plug Battery Positive cable Electrical junction Ignition module Figure 7 20 shows a typical wiring diagram for a remote key installation with the typical test points shown and the possibly faulty wires indicated If after testing the stop circuit you still have a prob lem with your engine not shutting down with either the key switch or the stop button the fault is in the CDI unit itself Unfortunately it s a solid state sealed de vice and is not repairable it will have to be replaced Mercury Tilt Stop Switch Testing Some mid sized and larger outboards have a switch designed to cut out the ignition if the engine is trimmed up too much It s located in
197. e with quick disconnect bullet type connectors you can use the same type to splice into the harness you re running from the panel to the player These bullet type connectors come in male and female halves and are a good way to ensure that the polarity of the equipment is observed Just make sure the correct connector ends up on the ap propriate wire Many installers cut off these bullet connectors and replace them with straight butt type crimp connec tors feeling that these might be less likely to corrode The truth is that this is not such a great idea for sev eral reasons First the standard male and female bul let connectors enable a quick disconnect in the event you need to remove the CD player for service or what ever reason and the connector can be reused when you reinstall it Second most bullet connectors that I ve seen have a rubber seal to minimize water intru sion Last these connectors are a good way to ensure that polarity is observed regardless of wiring color Figure 9 9 shows the bullet type plug connector in question For the installation of the wire for your new CD player follow the same ten steps for installing the cabin light and you ll be ready to go with the main wiring for the player Review the Step by Step In structions earlier in this chapter Keep in mind that many pieces of electronic equip ment today will have two positive feed wires one switched and the other intended to supply a constant DC
198. e you ll have to replace the assembly If all appears to be OK to this point push in the stop button and check your meter It should indi cate continuity with a low reading Finally if you have a stop clip pull it out and observe your meter reading It should again show a low reading If push ing the stop button or pulling the emergency clip does not give the desired low ohmmeter reading the assembly must be replaced Figure 7 19 shows a typical meter hooked up for these tests On larger engines with a remote starter switch you still check the switch for short circuits to ground you ll just have to cover the distance between your engine power head and the key switch Use your ohmmeter and your engine s wiring diagram just as before Identify all the terminals and connections on your key switch by removing the back cover of the control unit to get at the back of the switch Some manuals show a detailed picture of the plug assembly coming from the back of the switch and identify all Maintaining Marine Ignition Systems Fig 7 19 Multimeter tests of an outboard engine stop circuit the terminals and connections If you can get at the plug in this case you won t have to remove the re mote control assembly If removal and partial disassembly of the remote control assembly are necessary carefully follow the instructions for opening the control unit In some cases removal of the central pivoting screw can cre ate quit
199. ead Replace or repair these wires as needed If both of these leads are in good order and be having as they should the fault is in the instrument itself Figure 10 7 shows the wire disconnected at the sending unit and shorted to the engine block This is what your dash panel mounted instrument should read if the fault is simply with the sending unit which is the most common difficulty This test is for a one wire sending unit If your unit has two wires attached to it disconnect one of the wires from the sender and touch it to the terminal on the sender for the other wire Watch the gauge with the ignition on or get someone to watch the gauge needle for you If the needle moves as you connect these leads the problem is in the sending unit Fuel Gauges Fuel gauges are wired exactly as temperature gauges but use a different type of variable resistor as the sending unit The senders are located inside the fuel tank you need access to the top of the tank to locate the senders and the wiring To test the sender turn the ignition key on disconnect the wire from the sender and ground it at either the black lead on the sender or directly to the tank Observe the gauge Instrument Common Ground Engine or Tank Sending Unit Ignition 12V Fig 10 6 Simplified wiring diagram for temperature fuel and oil pressure gauges UTERE ere Bes ms r COMES Fig 10 7 Testing the temperature sending unit With the wire to the
200. ecific circuit operates Named labels have the advantage of not requiring a key to translate the number into a function but they also have several disadvantages For one thing they are not as neat and tidy as the numbered labels and most circuits will have more than one function re quiring more than one label You can get around this last objection by simply writing your own labels on white electrical tape with a permanent marker and wrapping it around the wire but it still is a bit messy especially on large or complex systems The labels also tend to fall off if exposed to solvents or fumes Colored Heat Shrink Tubing A great way to identify circuits is to provide each one with its individual color code applied with heat shrink tubing By using two colors for each circuit you can ID up to 25 separate circuits with only five separate colors if you use three colors for each circuit the total number of circuits jumps to 125 The big drawback to this system is that each wire must be disconnected at both ends before the heat shrink can be applied so it s very labor intensive when ap plied to an existing system However it s fine for additions to existing systems and when a boat must be completely rewired Colored Tape and Wire Ties You can of course apply the same color designation as described above using colored electrical tape which is easy to apply without disconnecting any of the wires The trouble with tape is that it is
201. eck into the cockpit I immediately altered course to investigate and found a fellow who was along with his entire family in a complete panic The fire had been started by a severe short circuit and the boat had no means of shutting off the electrical system Current from the battery was feeding the fire making it impossible to extinguish as long as the battery re mained connected There was no master switch of any kind It was an all too typical situation of a single battery installed on a small outboard powered boat I jumped aboard the runabout and cut the positive battery cable with a cable cutter I keep on board for working with heavy shark leaders The boat did have a working fire extinguisher aboard and once the bat tery was disconnected we were able to extinguish the blaze in time to save the boat Even so I m not sure if this fellow s family will ever again go boating with him on any kind of boat This little melodrama points out how important it is to be able to disconnect the battery power when there is an electrical fire It s imperative to disconnect the power before you attempt to put out the fire As long as there is battery current available your at tempts to stop the fire will be futile A 40 switch could have saved this fellow hundreds of dollars in damage and made his family feel a whole lot better Some Typical Selector Switches Let s look at some typical battery selector switches and learn how to deal with them
202. eck it against the specs in the workshop manual the ignition module is de fective and must be replaced Some ofthe latest CDI systems use a module with an integral trigger coil and the module is located un der the flywheel In this case you won t be able to get at the charge coil to service it and you won t find any reference to trigger coil testing in your workshop manual The flywheel must be removed to service these parts you ll need the services of a dealer or an other pro if your tests on the plugs secondary wiring and high tension coil lead you this far Problems with charge coils trigger coils and the permanent magnets under the flywheel are extremely rare and something that you may never have to deal with on your engine The only thing that usually causes early failure of these parts is accidentally sub merging the engine in salt water and not properly cleaning it A saltwater dunking will cause excessive corrosion in all the parts under the flywheel and in most cases ruin the engine if it isn t tended to right away If you should dunk your engine in salt water flush it with fresh water and get it to your dealer without delay So you have checked for spark to your spark plugs You now know how to check your system s spark with a simple spark tester You can remove your plugs check them and replace them when it s necessary You can check your spark plug wires and high tension coils and with the help of your work sh
203. ecommendations and advice in this chapter even a novice electrician can easily install all these things and many more Before You Begin Before installing any new electrical accessory there are some important things to consider Among the most important are the voltage and amperage that will be required by the new item However you must also think about the capacity of your distribu tion panel the fuse or circuit breaker you re going to use and the size of the wire and how you re going to run it Voltage Requirements You must be sure that the accessory whatever it may be is designed to operate at the system voltage in your boat Most small to medium sized powerboats today operate with 12 volt electrical systems Larger boats however may have 24 volt or even 32 volt systems Some even have systems that combine volt ages with certain items running at 12 volts and oth ers running at 24 volts Higher voltages are used on larger boats because the higher voltage is more effi cient and the builder can reduce the size of the 136 wiring and many parts A 24 volt starter motor is much smaller and lighter than an equivalent 12 volt starter motor for example With higher voltage wiring ampacity goes up as voltage increases This not only saves money but also considerable weight and the smaller wire is eas ier to work with If you recall from Ohm s law as we discussed in chapter 1 there is a direct and lin ear trade off be
204. ectedly So how do we verify the system is producing charging voltage It s easy if you have one of the in ductive ammeters described earlier Simply clamp the meter over the positive battery cable with the en gine running and rev the engine don t over rev it Most inductive meters work on a 100 amp scale so don t expect to see much needle movement Remem POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS ber this is a very low amperage charging system 4 maybe as many as 9 amps are all you can expect Op erate the engine at a fairly high rpm if the needle on the meter moves at all your system is OK If there is no movement visually check all the electrical con nections and terminals for corrosion and tightness Clean and tighten them as needed If your system is equipped with a fuse you should check it visually or test for continuity through the filament with your ohmmeter Check your engine s owner s manual for the location of the fuse if you have one If everything seems OK then the problem is probably in the rectifier Testing rectifiers is tricky without the wiring dia gram for your engine They don t all look alike and the wiring varies from one manufacturer to the next The best approach for rectifier testing is to refer to your engine s service manual All you ll need for equipment is your multimeter set to the diode test scale If you test the rectifier and determine that it s OK you must next test the stator These
205. ed antenna connection either at the radio or at any point in the antenna lead where a splice is installed to extend the lead For a simple so lution to this problem apply a light coating of sili cone lubricant to the center stud and threads of the barrel on the connector itself before screwing it into place This will provide a good watertight seal and keep the green gremlins corrosion away Regard less these connections should be checked at least once each boating season to ensure that no corrosion Coax Type versus Signal Loss in dB Fig 12 6 Signal loss in dB for cable runs of 20 and 40 feet using three popular grades of coaxial cable 185 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Fig 12 7 A Centerpin PL 259 CP coaxial coax connector exists Corrosion here will definitely create inferior VHF performance Eventually you may need to replace one of these coax connectors known as PL 259 connectors Hap pily a recent breakthrough in design has eliminated virtually all of the difficulty normally associated with this task With a standard connector you must care fully strip back precise staggered lengths of each of the three layers of coaxial cable down to the center core Once this is done you carefully insert the coax ial into the connector and either solder both the cen ter core to the center pin and the braided conductor to the outer body of the assembly or use special sle
206. ed arms 10 inches longer than normal to reach them Follow the steps I have outlined in this chapter and you ll make the correct starting system diagno sis every time without fear of unnecessarily replac ing expensive parts or of your spouse asking for a divorce Coast Guard Regulations for Starter Motors The U S Coast Guard mandates that like alterna tors and distributors starter motors used on gasoline powered boats be the ignition protected type discussed in chapters 4 and 7 This is serious busi ness and an area where I have personally seen more than one act of foolishness end in catastrophe A for mer student of mine owned a small marina that like most marinas did routine service on customers boats In a well intentioned attempt to save a few dollars for a customer my student this happened long before he was my student of course made the fatal error of installing an automotive starter motor in the customer s boat All went well until one day at the fuel dock the customer started his boat after a fill up A large explosion blew the boat to pieces killing the man The insurance investigator for this tragic acci dent traced the installation of the inappropriate starter motor to my student The customer s wife sued and ended up with a handsome settlement that included my student s boatyard He lost everything as a result of this one act of negligence The lesson here is obvious Do not even consider for a moment the
207. ed from voltage and am perage or information often provided by the appli ance manufacturer POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Fig 1 8 The power formula Like the Ohm s law equation the power equation can be used to determine the third value if two are known Multiply and divide just as with Ohm s law This is the pie formula which is useful for determining AC amperage All UL rated Underwriters Laboratory appliances must have either volts and watts or volts and amps indi cated on an attached sticker The sticker is useful for sizing circuit breakers and wire size Working with the Numhers A quick look at Ohm s law and the pie formula pre sented above and some brief experimentation with a few actual numbers illustrate the interrelationship of all the elements we have discussed so far As with any algebraic formula we can move and substitute values so that we can use the same formula written different ways to determine any of our electrical val ues as follows gt V AxR orvolts equal amps multiplied by ohms gt A V R oramps equal volts divided by ohms gt R V A or ohms equal volts divided by amps With the pie formula we get the following three variations gt W VxA or watts equal volts multiplied by amps gt A W V or amps equal watts divided by volts gt V W A or volts equal watts divided by amps So assuming a 13 5 volt constant the normal voltage in a charged 12 volt ba
208. ed to as capacitive discharge ignition CDI systems and we will take a closer look at them later in this chapter Ignition coil Fig 7 2 Typical outboard engine ignition system In this di agram the key components of a typical outboard engine ca pacitive discharge ignition CDI system are noted with their typical location shown Figure 7 2 shows the layout of a typical outboard engine CD ignition system Figure 7 3 on page 104 illustrates a typical PWC installation of this same type Maintaining Ignition Systems Maintaining your boat s ignition system is an easy task requiring just a little care and tidiness The biggest enemies to your ignition system are the same as those for any other part of your boat s electrical system It s just that the consequence of improper maintenance is more obvious in the ignition system because of the extremely high voltage found on the secondary side of the system Corrosion Protection All wiring connections and terminals need to be protected against corrosion On modern systems sealed Deutsch plugs are the norm today and they work exceptionally well requiring no maintenance Their three ribbed silicone rubber sealing rings ef fectively keep all moisture away from the electrical contacts inside the assembly Other systems using Maintaining Marine Ignition Systems Fig 7 3 Typical PWC capacitive discharge ignition system 1 Protective padding 2 Cover
209. ed wire and the black probe connected to ground Next have your helper turn the ignition switch to start If your boat has a starter button separate from the ignition switch turn the key on before pushing the starter button Make sure the transmission shifter is in neutral You should get a reading of approximate battery voltage as the engine cranks If you don t find battery voltage and the engine won t crank there is an open circuit which could be caused by a blown fuse between the ignition switch and the relay A third wire on the relay will have battery voltage present with the key on In some cases this terminal will be hot whenever the battery master switch is on If not trace this wire back to its source and repair the open circuit Use your wiring diagram to deter mine where the wire is connected to power If battery voltage is present determine if the re maining wire on the relay has battery voltage with the key in the start position If it does your starter circuit problems have nothing to do with the solenoid or Fig 8 4 Using an ohmmeter to check ground continuity at the solenoid Tracing and Repairing Starter Motor Circuits any of the wires going to it If it doesn t the solenoid is faulty and must be replaced Current Draw Test Measuring the current drawn by the starter motor as it operates will give you some important infor mation However specifications for the amperage drawn by different makes and mo
210. eded start up watt requirements of these appliances Be sure to check the specifica tions of the unit you re working with to make sure its rating is adequate In the case of generators if sized properly a typical 20 30 percent overrating for total maximum draw will take care of this mo E OER OAR ALE oM eiae che s etn seda e teet Tiel mentary need especially since it s unlikely that you ll have all of your appliances running simulta neously for an extended period of time Total wattage Fig 11 16 Wattage load analysis sheet for inverter or generator selection Amp Hour Calculation Table for Inverter Battery Bank Sizing Use Time Minutes Hours Amp Hours Used Typical Appliance Jhr 2hk 3hr 8hr 24hr 13inch color TV EIN EE DICEN UE Sed DUE TAE T A 110 VRE E Deere ie MSE RAE ror aE DBR cd DOCE NS D ene et Ace cos RET 110 CUI O RE EET rwr lcm 2 Tablelamp le QU CN ER Siento DUE eE 205 ves VIDT 221 THOME AUNPIUINY a aa E EE T E DU Qut qug mes Se tia 110 Blender ee ar va E NU QM EE TESSUTO 14 PANON RE TETTE A s Zier 23 ZUOECUNIITETTIQTUIO ERE TETTE TET TT EETAS REE A oso nee D cscwse TIET 550 Mid size microwave Te oT 20g ies ess Bate em TO NR 249 Coffee maker NES TES 239p at dM sa nncve 02 thoes 183 Vacuum cleaner ieee eee BO 10 esee 20 RUN 302 Fullsize microwave Loree nee 94 ero 60 38 eeenoc 252m 413
211. el lent performance provided the basic rules for lo cating it are followed In addition to the location requirements already noted make sure the trans ducer is positioned so that its face is aimed straight down and not canted to one side or the other If you want to mount the transducer on an angled section of the hull a mounting pad is required Use an ap propriate material for the fairing block see below and make sure the stem of the transducer is com pletely sealed so that water can t leak into the boat It s also important that water not come into contact Plain Washer 5200 Adhesive Mounting Pad Rubber Washer Fig 12 11 Through hull mounting of transducers with fair ing blocks with the freshly exposed fiberglass or core material around the perimeter of the through hull hole a leak here exposes the laminate or core to water and can damage the laminate as water attempts to mi grate into it 3M 4200 or 5200 works well for this purpose As for the material to use for the fairing block stay away from wood Traditionally wood has been the material of choice for this job but today it s un necessary and less desirable than modern materials such as Delrin or Marelon These miracle plastics are now used for making seacocks and other through hull fittings and are widely used in other industries They are available in sheet and block form from in dustrial supply houses The beauty of using
212. em Components The key ingredients in the recipe for this witch s brew of electronic and electrical apparatus that makes up your ignition system are as follows one battery one control module one distributor with cap several yards of ignition wire and one spark plug for each engine cylinder Let s take a brief but close look at these ingredients one at a time I will have alot more to say about all of these items later in the chapter Right now I just want you to know what they do Ignition Control Module The ignition control module called the capacitive discharge ignition or CDI unit on PWCs and out board engines we ll look at this in more detail later in the chapter is the little black box that coordinates and controls all the various functions of the igni tion system It s usually one or more computer Copyright 2000 2007 by Edwin R Sherman Click here for terms of use chips and when it malfunctions there is nothing to do but replace it with a new one There are many dif ferent designs of these modules and no two engine builders use just the same one To be useful in an ignition system the high volt age produced in the secondary coil windings needs to be continuously turned on and off as the engine runs This ensures that each cylinder gets spark at exactly the right time With early ignition systems before ignition control modules breaker points acted as the switch for the primary voltage On today s en
213. emaining possibil ity is that there is a problem in the gauge itself and a new unit should be installed Note One slight possibility is that the tachometer is not getting a signal from the ignition system via the gray wire from the ignition system it self but this is extremely rare and al most always associated with an ignition system problem as well If you need a new tachometer make sure to follow any calibration instructions provided with the gauge Manufacturers generally provide one gauge for four six and eight cylinder engines The correct number of cylin ders should be set using a small cali bration screw on the back of the gauge as shown in figure 10 4 Select the set ting that corresponds with the number of cylinders on your engine If you have a diesel or gasoline en gine that uses the previously mentioned tach sensor at the alternator you still need to verify that the tachometer is getting 12 volts with the key on and that it s connected to a good ground If you find that everything I have mentioned so far is in order and your tachometer is still not reading the problem may be an open circuit in the 151 132 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS sensor wire from the alternator to the tachometer or a fault within the alternator itself Since this sensor wire is sensing voltage from within the alternator no signal here means no voltage inside the alternator The basic checks of the chargi
214. emoved and im properly reinstalled the flywheel becomes loose on the end of the crankshaft and shears off the key The flywheel may spin independent of the crankshaft and change position of the magnets relative to the crank shaft ruining the ignition timing To check for a loose flywheel disconnect the mas ter plug to the ignition module to disable the ignition system you don t want the engine starting with your hands on the flywheel Next grasp the flywheel firmly with both hands and feel for any side to side or up and down movement as shown in figure 7 22 Any movement indicates a loose flywheel An experienced mechanic must remove the flywheel and the crank shaft and flywheel must be inspected and repaired or replaced as needed With luck you ll just need to install a new key and to re torque the flywheel Fig 7 22 Checking for a loose flywheel 121 122 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Timing Check If all wiring is properly connected and your flywheel is secure a timing check is in order This is not a pro cedure for the inexperienced outboard engine me chanic The procedure varies somewhat for every outboard made and verifying the position of the ignition timing pointer is a precise and difficult job requiring special tools that the average boatowner won t have The timing should be checked at idle and for maximum advance at high speed This is best done in a special test tank or with the aid
215. ent discharge 45 amp hours x 2 650 cycles 0 0017 per amp hour Gel cell 86 amp hours 2 50 percent discharge 43 amp hours x 1 400 cycles 0 0027 per amp hour AC RE 92 amp hours 2 50 percent discharge 46 amp hours x 3 000 cycles 0 0014 per amp hour Please keep in mind that these costs are based on charge cycle numbers that are quite high In actual use your cost per amp hour will probably be much higher However on average the findings here are as good for comparison of battery types as any other method Although they will require more maintenance than other types conventional wet cell batteries are still the least expensive of the three types to buy and own over the long haul AGM batteries offer all the advantages of the gel cells plus a less finicky charge cycle Therefore in almost all applications AGMs are a better choice than gel cells but as of this printing you ll still pay a substantial premium for AGMs over wet cell batteries AGMs are a particularly good choice for installations where acid spills are a consid eration as with personal watercraft Jet Skis and other sport boats and they are excellent for use on boats that will be left unattended for months at a time Which Battery Is Right for You All but the smallest open boats should have at least two batteries The starting battery is for starting the engine and needs a lot of cranking capacity to spin a heavy du
216. ent of its total wattage most of the time Knowing this it should be clear that running a TV from even 175 176 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS the smallest generator will damage the unit if that s the only draw for extended periods Generators are really only suitable for fairly serious AC loads such as electric ranges air conditioners and hot water heaters all running simultaneously and for extended periods of at least and hour or so for example dur ing preparation for the evening meal Other serious disadvantages of generators include the noise ofthe engine those wonderful exhaust fumes permeating into the pre dinner cocktail hour and simply having one more engine on board to maintain As already mentioned both the voltage and fre quency of AC generators are carefully controlled by an engine mounted governor that keeps engine rpm stable under all electrical loads If you have a genera tor on your boat your AC panel must have a volt meter to be in compliance with the ABYC standards It s a good idea from time to time to monitor this gauge Any variation in voltage beyond 10 percent of the normal rated output for the generator that s indicated by this gauge is an indication of trouble Modern generators are commonly regulated to control voltage to as little as plus or minus 2 percent if all is well with the unit As voltage fluctuates so too does frequency Normal frequency here in the United States is 60 H
217. ents on twin engine boats duplicate instruments for each engine often give conflicting readings This is normal and no prob lem once you understand what is going on Many older boats use mechanical gauges and much of the information provided in this chapter on elec trical troubleshooting will not apply to these instru ments It s a good idea to determine what kind of 17 gauge you have before a problem does crop up so you ll have some insight into what the best plan of action may be Look at the back of the instrument If it has nothing but wires connected to terminals it s an electrical instrument However if you see any kind of non electrical tube or cable in addition to one or two wires you probably have mechanical gauges The wires are for the instrument lights Many boats have a combination of mechanical and electrical gauges Most small to medium production boats built today use only electrical gauges mostly because they are alot cheaper and easier to install than mechani cal ones Since this book is intended for outboards and smaller powerboats generally powered by IO drives or gas inboards I ll focus on problems with the electrical instruments on these boats and leave the mechanical gauges alone Common Instrument Interpretation Problems There are several things to think about when you re viewing your boat s instruments For example con sider the actual accuracy of the instruments For rea sons that will be poi
218. er Fig 4 5 Table VIII from section E 11 showing insulation markings and temperature ratings for insulation on flexible cords as used on board ABYC Wire and Circuit Protection Standards and Repair Procedures Fuses If you were ever foolish enough to connect the posi tive and negative terminals of any 12 volt battery with a length of wire with no intervening load to slow the flow of electrons the wire would immediately be come red hot and melt This is how an unfused short circuit can quickly destroy a boat and it s how a fuse works If you interpose a short piece of smaller gauge wire into this ultrasimple circuit the smaller wire will self destruct and stop the flow of electrons before the heat builds up enough to damage the larger wire CONDUCTORS TYPES DESCRIPTION SEE NOTE TH Moisture and heat resistant thermoplastic T HWN Moisture and heat resistant thermoplastic resistant 1231 1232 1275 thermoplastic thermosetting A 1344 1346 ftw Moisture resistant thermoplastic W W XHHW Moisture and heat resistant cross linked synthetic polymer MTW Moisture heat and oil resistant thermoplastic WM Style Nos 1230 moisture heat and oil You have in effect built yourself a fuse in the form of the smaller wire You might recall that in chapter 1 I noted that a by product of resistance is heat Well a fuse is de signed with an element that will carry a certain amount of current
219. er tently become connected intermittent rating See continuous rating internal short Short circuit within the case of an electrical appliance inverter voltage A device that converts DC voltage to AC joule A measurement of energy One Joule equals one watt for one second jumpers Short lengths of conductors either wire or strapping key To activate kilo k A common prefix meaning 10 to the third power or 1 000 lead A length of wire usually fairly short As in meter lead lead acid battery Typical battery using lead plates and sulfuric acid electrolyte LED outlet tester Tester used to verify AC plug outlet wiring connection status that uses light emitting diodes LEDs to signal status of con nections at the outlet and its connected wiring life cycles The estimated number of times a battery can be discharged to a specified level and brought back up to full charge before it fails live Meaning power is available load Any device in a circuit that dissipates power lugs Ashort threaded stud used for wire termination GLOSSARY magnetic circuit breaker Breaker that uses the magnetic field generated by a current carrying coil to open the circuit magnetic field Magnetic lines of flux invisible but present around all conductors with electrical cur rent flowing through them The magnetic lines of flux surrounding the Earth are the basis for the function of a magnetic compass magnetic sepa
220. er OMC Volvo Penta and US Marine are shown with the ter minals identified You ll need your engine s service manual to match the wiring harness to these diagrams Charging System Symptoms Regardless of the charging system used on your boat the following symptoms usually indicate a problem 1 Constant undercharging of the battery indi cated by poor battery performance 2 Constant overcharging of the battery indi cated by having to add water electrolyte accu mulation on the top of the battery or a rotten egg odor in the area of the battery 3 Abnormally high or low voltage or amperage readings from any meters installed in your system when the engine is running 4 A noisy alternator 5 A constant whirring noise from radios or a sudden reduction in signal strength with Lo ran C receivers Simple Checks When you experience one of the above symptoms or when you otherwise suspect you have a charging sys tem problem several preliminary checks should be made before you assume the worst and replace your alternator Belt Tension and Replacement First check the belt that drives the alternator to see if it s too loose Alternator drive belts as shown in figure 6 2 should have no more than about inch of deflection for each foot of span between pulleys If the belt is loose inspect it for excessive wear Any fraying of the belt s edge or cracks or grooving in the belt indicates that it s time for a replacement
221. er motor Starter grounded to solenoid 131 132 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Finally connect the meter as shown in figure 8 7d on page 131 with one probe connected to the body of the starter motor scrape away a little paint to be sure of a good contact and the other probe connected to the negative terminal on the battery Turn the key to start Your voltage reading should be less than 0 3 volt If the reading is higher either a connection is bad at the engine or at the negative battery post or the cable is undersized It should also be the same size as the main battery cables This test will work with any starter circuit in board or outboard and the values for allowable volt age drop given here apply to all systems using a 12 volt power regardless of engine size Also you may notice that the total voltage drop may exceed the 3 percent mentioned earlier in this book Oddly enough the total individual voltage drops may fall somewhere between the 3 and 10 percent limits discussed I have always felt that the 3 percent maximum is most important for a starter motor circuit meaning that the total voltage drop would be no more than 0 36 volt for the entire circuit Having said that I can tell you that engine service manuals consistently use a 0 2 volt maximum drop for all the connections and parts up to the starter motor and 0 3 volt back to the battery as the acceptable limit this giv
222. er things than new bat teries on which to spend your boating dollars so this chapter is dedicated to seeing that you get the max imum life and performance out of your batteries by recharging them properly There are many acceptable ways to recharge boat batteries Auxiliary generators wind driven genera tors solar panels and water driven generators are all used on boats in varying circumstances However the vast majority of us weekend powerboaters with small to medium sized powerboats rely almost en tirely on the engine driven alternator and shore powered battery chargers to keep our boat s batteries up to snuff Thus I am going to concentrate on these two methods of recharging and leave the others alone I will however close this chapter by touching on solar powered means of keeping batteries topped up and ready to go boating Alternator Basics Many books that cover the subject of alternators go into all types of alternator internal testing proce dures and into details of how alternators actually work I m not going to do that in this book for just the same reasons I didn t go into great detail on bat tery chemistry It s way too complicated to be cov ered quickly and it frankly isn t very practical information for the average boatowner You want to know how to tell if your alternator is working and if it isn t you need to know how to fix it Everything else is excess baggage so we are going to avoid it You
223. ere is still a remote possi bility that your CDI unit is acting up Unfortunately questions with the CDI unit may require you to rely on your dealer s expertise for some tests particularly on mid sized to larger outboard engines However if you have a no spark condition and you have care fully performed all of the tests outlined above you can feel quite comfortable purchasing a new CDI unit and installing it That was your problem Other problems with the CDI unit are a little more difficult to pinpoint Your system may have a built in rpm limiter or a slow down circuit designed to reduce engine rpm if the engine overheats If all of your other tests point to the CDI unit in anything other than a no spark situation inform your dealer of everything you have done and rely on the dealer to make the final decision on replacing the CDI unit Dealers will not accept returns on electrical parts so trial and error methods of testing can be expensive Optical Timing Systems If you own a medium to large outboard made within the last several years you may have a subsystem inte grated into your CDI unit called optical timing This is a very sophisticated system that electronically controls the timing advance and retards the spark for easier starting Unfortunately troubleshooting this system requires an arsenal of specialized test equipment and adapters If your engine has an optical timing system consult your dealer for diagnosis once yo
224. eries and the even newer absorbed glass mat AGM batteries so let s take a close look at each of these three Wet Cell Batteries Wet cell battery technology has been around since the days of the first electric start automobiles This is the type of battery with the removable cell caps generally but not always with which we are all fa miliar because it s the type still found under the hood of the family car Wet cells have the lead plates suspended in liquid electrolyte and the durability of the individual batteries depends on the robust con struction of the case and grids as well as the amount of material in the plates Even today wet cell batteries offer some impor tant advantages over gel cell and AGM batteries the new kids on the block They are usually the cheapest to buy initially and as we will see below they are by far the cheapest to use over the long haul provided of course that you don t neglect regular mainte nance They also stand up well to abuse such as over and undercharging The disadvantages of wet cells are that they re quire more elaborate ventilated battery compart ments They will not hold a charge as long as the newer gel cells and AGMs which means that they can t be left unattended for as long They must be Batteries and Battery Systems kept upright at all times and they require regular topping up with distilled water Gel Cell Batteries Gel cell batteries work on the same principles
225. ers essen tially all look alike and the only way to be certain of their ratings is to read the label affixed to them The problem is some of these labels are located on the side of the breaker requiring removal of the breaker from the switch panel to be certain of the amperage rating These labels are typically glued on paper labels that af ter a few years in the marine environment dry up and fall off or become very hard if not impossible to read Fortunately removing a circuit breaker from its holder is a straightforward procedure First be sure to turn off the master switch feeding the distribution panel to avoid arcing any wiring as you remove the breaker Next back out the one or two screws adja cent to the switch handle on the face of the panel and 51 52 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS slide the breaker out from the back Figure 4 11 shows the screws on the face of the panel holding the breaker in place and figure 4 12 shows the breaker with the specification label showing the unit s ratings removed Ignition Protection Electrical ignition protection regulations for gaso line powered recreational watercraft go beyond the ABYC s voluntary standards and are enforced by the United States Coast Guard ABYC section E 11 defines ignition protection in these official words Ignition Protection The design and construc tion of a device such that under design operating conditions it will not ignite a f
226. ery The difference between batteries is not only in the physical construction but in the ratios of lead perox ide and other materials such as antimony and a cal cium alloy used in constructing the battery s plates and in the amount of material used in the plates These variations affect the number of times a battery can be cycled the number of times a battery can be discharged and then recharged and still come back to useful life The construction of a battery also affects how long it can remain discharged before the lead sul fate hardens to the extent that recharging can t re verse the chemical reaction When this happens the battery is said to be sulfated and must be replaced These chemical and construction variations in bat tery types also explain why some batteries have a tendency to produce more hydrogen a process called gassing than others Engineers have been able to reduce gassing to al most nothing by adding antimony into the plate ma terial Less gassing means less water loss and hence the evolution to the sealed batteries which are be coming the norm today We now enjoy modern gel cell or absorbed glass mat AGM technologies that keep the sulfuric acid in either a gelled state or ab sorbed in a mat material much like conventional dry cell batteries The first basic choice you ll have to make as you try to pick out a battery for your boat is between the old technology wet cell batteries the new gel cell batt
227. ery Amp hours CCA 24 85 500 700 27 100 550 800 4D 150 180 1000 8 D 200 225 1175 GOLF 200 225 1500 1600 might just find that a bargain battery might not be such a bargain after all Marine Cranking Amps versus Cold Cranking Amps Most medium sized boats need a cranking battery with enough cold cranking amperage CCA to get the engine going but it isn t that simple any more A new classification has been added to the mix and some vendors are now rating the batteries they sell in marine cranking amps MCA in place of cold cranking amps As defined by the ABYC the two definitions are Battery cold cranking performance rating The dis charged load in amperes that a battery at 0 F 18 C can deliver for 30 seconds and maintain a voltage of 1 2 volts per cell or higher Cranking performance also referred to as marine cranking amps at 32 F or MCA at 32 F The dis charge load in amperes that a new fully charged battery at 32 F 0 C can continuously deliver for 30 seconds and maintain a terminal voltage equal to or higher than 1 20 volts per cell Fig 5 2 Common battery group sizes amp hour ratings and dimensions Notice the 32 variation in the two ratings This means that if two batteries with the same amper age one using the MCA rating and the other using the CCA rating are being considered the one us ing the CCA rating will be the more powerful battery Battery potential decreases
228. es Figure 7 11b shows a spark gapping tool being used to adjust the electrode gap Engine Stop Control Last but certainly not least is the stop control the device you use to shut off your engine by disabling your ignition system Depending on the engine the stop control might be activated by a simple stop but ton or on larger engines by a key switch On newer engines you ll find an emergency stop button with an overboard clip and lanyard wired directly to your system s CDI unit When the lanyard is pulled the clip is yanked out of the stop button This creates a momentary short circuit inside the CDI unit that di verts the voltage intended for the high tension coils directly to ground and shuts off the ignition long enough to stop the engine These stop circuits can cause a lot of problems and procedures for testing Fig 7 11b A spark plug gapping tool them will follow a little later in this chapter Outboard and PWC Ignition Tests The first step with all electrical circuit testing is to carefully use your eyes Look for the obvious When ever a problem develops with any engine or system that has been regularly maintained troubles are al most always due to some minor oversight and are easily solved Check all the wiring for any loose con nections on your engine Look for signs of corrosion on terminals and connectors Check for any broken or frayed wires Make certain the problem is not something as silly as a blown
229. es a maxi mum of 0 5 volt The truth is a well done factory cir cuit will give voltage readings well below the 3 percent tolerance and I prefer to use that figure for my own criterion I mention the 0 2 and 0 3 volt specifications here only because I know you ll run into them if you follow your service manual as you should when doing these tests Testing the Neutral Safety Switch If your boat has remote engine controls with the shift lever and ignition switch at the helm the neutral safety switch is located inside the control unit Therefore you should never attempt to diag nose problems with this switch without the aid of the workshop manual for your engine and control unit There are just too many variables in wire color coding and control unit disassembly procedures to cover them all here In fact unless you re fairly confident as a mechanic you should never remove or attempt to disassemble the remote control unit It s full of spring loaded levers shims and cable attachments that are critical in their placement and function So beware However it s quite easy to check all wiring and parts affected by the neutral safety switch enabling you to consult intelligently about the problem with your mechanic Your neutral safety switch is electrically con nected to both your ignition switch and the starter solenoid When you shift into neutral the switch should close completing the circuit between the ig nition switch and
230. es are in order In other words it s time to assemble our monster Beginning with the series circuit remember that there is only one path for electrons to flow through out the circuit Here s what happens as amperage which you ll recall is the volume of electrical energy flowing through a circuit travels through the circuit voltage the electrical potential is used up and re duced as the current amperage encounters resis tance ohms and is converted to power wattage This reduction in voltage is referred to as voltage drop The sum of the individual voltage drops mea sured at each component in a series circuit is equal to the original source voltage The total circuit resis tance in a series circuit is the sum of the individual resistance values of each load resistance in the cir cuit The same amperage will flow through each re sistance in a series circuit but the voltage is divided and shared by the loads in the circuit In the parallel circuit there is more than one path for electrons to follow and this changes the charac teristics of the circuit considerably First having more than one path reduces the inherent circuit re Electrical Basics You Need to Know sistance The total circuit resistance in a parallel cir cuit will always be lower than the resistance for any single resistance in the circuit Current amperage will vary as it feeds each individual resistance in the circuit to the extent that the resistanc
231. esel fuel quality These hydrometers are all different and cannot be interchanged and they are designed and calibrated against a standard for the liquid you re checking A battery hydrometer is used to check the state of charge for each cell of a wet cell battery This test can only be performed on batteries that have remov able cell caps not gel cells AGMs or sealed no maintenance batteries Do you remember when I explained how a bat tery works I described a chemical reaction where the acid is absorbed into the battery plates leaving only water The hydrometer measures the change of the electrolyte from acid to water and tells us the per cent of charge of each cell in the battery Knowing the percent of charge does not tell you whether or not you need a new battery If all the cells are equally low something is either discharging the battery or you have a charging system problem The only other pos sibility is that there are one or two bad cells and the battery has discharged the good cells into the bad cells equalizing the hydrometer readings You re looking for a different reading between cells If all the cells are equally low recharge the bat tery and recheck the specific gravity for any varia tion between cells One low cell after recharging indicates a battery on its way out Three very important points must be made re garding specific gravity testing 1 Don t attempt the test immediately after adding water to a ce
232. eves to compress all of the components of the coax ial into place With the new solderless connectors all you do is to cut the end of the coaxial cable square firmly push the cable into the new connector squeeze together the locking arms and thread on the outer cover of the connector These connectors are sold as Centerpin PL 259 CP connectors and truly take the work out of this usually finicky task shown in figure 12 7 Figure 12 8 gives a complete VHF installation overview from the DC distribution panel to the radio and from the antenna to the radio As a final note to these instructions for VHF in stallation and general use remember to check your radio on an appropriate channel each time you take your boat out This is not at all frivolous In my ex perience most failures with VHF radios occur on the transmitter side of the circuitry not on the re ceiver side So simply turning on your radio and lis tening to the chatter on various stations is no assurance that the radio will work as it should if the need to call for help ever arises Be certain always check for both transmission and reception before leaving the dock Remember your VHF is an im portant safety tool not a toy Respect and use proper radio etiquette at all times You ll greatly appreciate this minor formality if you ever do need to use your radio in an emergency DC Panel Antenna Installing a Fish Finder or Depth Sounder In terms of functional
233. f Fire Island for a fin ished set of drawings After all that would be fun and isn t having fun what powerboating is all about Chapter 3 Selecting and Using a Multimeter Multimeters A multimeter is a highly versatile measuring and testing tool that will be essential for performing a great many of the tests and procedures that we will be covering in the rest of this book It s one of the first tools that you as an aspiring marine electrician will need to buy and it s by far the most important With your multimeter you ll be able to make quick and accurate measurements of all elements of your electrical system and you ll rarely approach any electrical task without it in hand Back when I first started in electrical work a good and expensive multimeter was already one of the most important tools in my toolbox However there are profound differences between the cumber some multimeters of only a few years ago and the sleek digital marvels we have today My first meter was a 4 inch thick 6 by 8 inch black box fes tooned with knobs and terminals and a large white dial with some six or eight scales printed on its face In those days the better and more expensive a me ter was the larger it was simply because a large ana log scale is much more accurate and easier to read than a small one To use this beast I would select the range of the scale I wanted set the function zero or calibrate the meter needle connect the probes
234. f several generating processes is just that We have all felt the shock of static electric ity after shuffling our bare feet across a wool rug Electrons stripped off the rug by the friction of our feet build up in our body then when we grab the doorknob the circuit is completed the excess elec trons rush back into the carpet and we get a jolt sometimes quite a strong jolt of electricity Over the years many analogies have been con trived to explain the electricity phenomenon none of which is entirely satisfactory One such analogy compares electricity to a tank of water with a hose attached and another compares it to a looped tube full of Ping Pong balls that endlessly push each other around in a circle Yet another uses horses gal loping around a racetrack to try to help us visualize electrons racing around an electrical circuit While all of these picturesque analogies help to explain some aspect of electricity comparing a battery to a water tank for example works quite well none does a good job of explaining them all In the following pages we break electricity down into its fundamental elements then once an under standing of each of these elements has been estab 1 lished we put them together into the finished prod uct We proceed slowly and collect and study all the component parts then once we have a good under standing of them we assemble them into a complete picture Those readers who already have a goo
235. f the fuse or circuit breaker used in each circuit must be clearly indicated Each wire to and from each component in the boat must be identified on the diagram by color and number or label depending on how this marking is applied The gauge of every wire in each circuit should be shown Figure 2 2 shows an example of a diagram with all the elements described above Figure 2 3 shows a far less descriptive diagram which was the norm for years This one may look a lot like the one that came with your boat Component Identification If you re new to marine electrical systems one of the first things you should do is learn to identify the wiring and the major components of a circuit Get ting a positive ID on such items as bilge blowers bilge pumps and cabin lights is easy because you can tell what they do just by looking at them but what about the other required components in the circuit Where are they and how can you begin to determine which wires feed what circuits as you look at the multitude of choices behind your distribution panel Figure 2 4 shows the back of a typical master dis tribution panel with all the key components identi fied For a further explanation of what these NOTES 1 2 3 4 TRIM SWTICH TRAILER SWITCH START CIRCUIT NEUTRAL SAFETY AND EMERGENCY SHUTDOWN SWITCHES LOCATED AT SHIFTER SOME EQUIPMENT MAY NOT BE INSTALLED ON ALL MODELS FUSEBLOCK POWER SUPPLIED BY ENGINE MOUNTE
236. f the light fixtures the fuse for that fixture would blow leaving the others still working A dead short in the main circuit however would trip the cir cuit breaker and extinguish all the lights Ampere Interrupting Capacity The amperage rating of a circuit breaker is calculated as a percentage of the current carrying capability of the smallest wire in the circuit There is an additional rating known as the ampere interrupting capacity AIC that is a peak rating taking extreme situations such as catastrophic short circuits and other surges into account As a user you need not worry about the AIC rating as all the reputable producers of ma rine circuit breakers take these values into account Trip Free Breakers ABYC specifications state that all circuit breakers used in pleasure craft be of the trip free type defined as a resettable overcurrent protection device de signed so that the means of resetting cannot over ride the overcurrent protection mechanism This is an elaborate way of saying that they don t want you to be able to override the breaker by holding it closed once it has tripped With trip free breakers the prob lem that caused the breaker to trip in the first place must be located and repaired before the circuit can be reactivated Types of Circuit Breakers There are two kinds of circuit breakers commonly used on today s boats Bimetallic breakers sense re sistance generated heat and magnetic breakers se
237. fers some significant technological advantages over the Thunderbolt IV system the most significant of which is known as the knock retard spark control This feature is a giant step forward in avoiding internal engine damage due to pinging Engine cylinders are designed so that the compressed gas air mixture burns very rapidly but progressively When the mixture explodes instead of burns a loud rapping or pinging noise is heard Thus pinging is sometimes called detonation Whatever it s called pinging is bad for your en gine Incorrect timing low quality fuel or excessive carbon buildup inside the combustion chamber are the primary causes If it s allowed to continue ping ing will eventually cause valves and piston tops to literally melt away By adding two electronic devices to the ignition system engineers have devised a way to minimize Fig 7 8 MerCruiser ignition sensor pointing out metal jumpers These jumpers are famous for corroding through effectively shutting down your ignition system Fig 7 9 Retaining screws holding an ignition sensor in place 109 110 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS pinging as a cause of engine damage The knock retard spark control is operated by one of these two additional devices The knock control module receives an electrical signal from a sensor called a knock sensor which is screwed into the engine block This sensor hears any pingi
238. few years old it may not comply with all of the standards outlined in the ABYC s Recommended Standards and Technical Information Reports This is not a cause for immedi ate concern These standards have evolved over the years and have been revised as new materials and technology became available The tables charts and recommendations in this chapter and in the rest of this book reflect the recommendations of the ABYC at the time this book was written Wire types and cir cuit protection ratings are not likely to change in the foreseeable future On the other hand there could be breakthroughs in insulation technology as newer and better materials are developed and a technolog ical advance might create a new circuit breaker that will be better than the ones we use today If either of these events should transpire rest assured that the ABYC will take a close look and make appropriate recommendations based on what they see Basic Wiring The ABYC electrical standards go into great detail on the minimum criteria for both DC and AC cir cuits used on boats Basic considerations include the length of the wire nominal voltage amperage rout ing of the wire insulation temperature rating and the chemical environment to which the insulation is likely to be exposed One additional consideration is the conductive material used in the wire Wire Types Electrical wire comes in a variety of types and con ductor materials but by far the most
239. flow past this heat sink is adequate to provide necessary cooling when the equipment is in use Proper cooling 144 Fig 9 8 Typical electronic equipment heat sink of the equipment will improve its longevity and per formance How much cooling air is enough Not much just don t stuff your valuable CD player into a tiny hole with no room for air to circulate Once you decide on a good location for your new CD player and cut the necessary mounting holes you re ready to wire it in Pm sure you remembered to check the packaging before you left the store after buying the player Quite often the installation in structions include a template for the mounting cutout Having this template will save a lot of time and ensure that you get a proper installation with a minimum of fitting As with any electrical equipment always follow the fuse recommendations provided by the manufac turer Most CD players come with a two wire harness about 18 to 24 inches long with an in line fuse holder already installed on the power lead Typically these leads are made with 16 AWG wire Since most such equipment but not all draws less than about 1 5 amps 16 AWG is usually large enough for runs of up to 30 feet where the CD player is located 15 feet away from the power source If the distance from the power goes over 15 feet step up to 14 AWG In this example using the 3 percent voltage drop from chapter 4 for a circuit length of 30 feet 1
240. fuse Any of these things can be the cause of ignition problems and they can be quickly fixed with basic tools Testing for Spark As with the inboard systems the first step in trou bleshooting your ignition system is to verify that you re getting spark However with outboard and PWC systems you need to check each cylinder because each cylinder has its own high tension coil and partial system failures of one cylinder are not uncommon When checking the coils it s extremely important that you check for any fuel leaks and make certain that all fuel line fittings and connections are secure It is a good idea to create some shade near the Maintaining Marine Ignition Systems Adjustable Knob Attach to Spark arcs here Spark Plu Wire attaches here Fig 7 12 Snap On spark tester I prefer this type over all others because it s adjustable which gives you the ability to determine the strength of the available spark spark plug wire you re checking It s very difficult to see a spark jump a gap in bright sunlight Use the spark tester shown in figure 7 12 Adjust the knurled knob on the tester to give an air gap of about 75 to 7i inch between the two pointed contacts inside the cylinder Figure 7 13 shows the spark tester properly connected and ready to go Hold the tester so you can see inside the cylinder as shown and crank the en gine You should see a bright blue spark not yellow jumping between the tw
241. g to work with AC regularly this is a good added feature to have on your meter Checking AC Amperage Checking AC amperage through a circuit can bea bit tricky The problem is that since sheathing pro tects AC wiring through most of its length it s some times tough to find a single conductor around which to clamp your meter to take a reading Remember that with an inductive clamp type ammeter you can only use one conductor to measure amperage This applies to both AC and DC The truth is this is not a reading you ll be making very often because AC ap pliances all provide the data needed to determine amperage The need to actually measure amperage in AC systems is far less of an issue than it is with DC circuitry Figure 11 13 shows an inductive AC clamp meter being used to determine current in an AC circuit AC Continuity Tests Continuity tests for AC circuits are more frequently needed than are voltage and amperage tests and the ability to perform a good continuity test will be use ful especially when checking things like shore power cords The most important point to remember when checking for continuity is to be certain the wiring that you intend to check is disconnected from the power source The risk here goes beyond simply damaging your multimeter it s also a shock hazard Continuity tests can be used not only to determine the integrity of wiring but also to check some resis tive AC appliances things such as a hot
242. ge in others Falling oil pressure might be accompanied by rising engine temperature and falling rpm for example When this occurs you must respond quickly and verify that a problem does in fact exist Ask yourself Is there really a problem or is the gauge just acting up Initially you must assume that a problem does exist and immediately shut down your engine until you can verify that it s OK Verification of engine condition requires some mechanical expertise on your part and if you re in doubt you may need to consult an experienced me chanic This works fine at the marina but offshore it won t be possible to call a mechanic so some basic tips are in order If your boat has an outboard engine my book Outboard Engines Maintenance Trouble shooting and Repair will surely help you solve most common problems If yours has an IO or inboard en gine the following steps should point you in the right direction Low Dil Pressure When your oil pressure gauge gives you a low oil pressure reading immediately shut down the engine and check the engine oil level Refer to your owner s manual to determine the correct level if you don t al ready know it While you re at it look for any signs of leaking oil If the oil level is correct an oil pressure problem is quite unlikely unless your engine has many hours on it over 1 000 hours for gas engines and even more for diesels Excess engine noise such as tick ing sounds coming fro
243. gh the distributor cap and additional ignition wires to the individual spark plugs Inside the spark plug the voltage comes to a dead end where in a fit of in tense frustration it leaps across a precisely cali brated air space creating the spark that ignites the fuel vapors in a cylinder of the engine If several hundred other engine parts are all doing their thing at precisely the right time you re on your way If not it s time to break out the oars or look for a 100 tow Fortunately such malfunctions are unusual because the modern ignition system is about as de pendable as electromechanical contrivances can get But they do on occasion fail and when they do you ll want to be able to identify and deal with the problem That s what this chapter is about To maintain and troubleshoot your ignition sys tem you need a basic understanding of how it works Most people I talk with about marine elec trical systems begin with the feeling that they really know what s going on with their ignition system Then I probe a little and find that in most cases they know just enough to be dangerous Quite often when there is an ignition system failure all the ex perts on the dock come up with some interesting suggestions for this or that All of this free advice in my experience adds up to the boatowner replacing perfectly good parts Knowing how your system works will go a long way toward eliminating this problem Inboard Ignition Syst
244. gines 106 7 fish finders 189 90 ignition systems 106 7 starter motor circuits 125 28 126 127 tachometers 149 150 52 temperature fuel and oil pressure gauges 152 55 transducers 187 90 T type fuses 48 49 141 174 20 hour rating 71 undercharging batteries 76 86 89 Underwriters Laboratories UL 8 52 160 ungrounded conductors 158 U S Coast Guard regulations 40 102 123 US Marine 88 89 V VHF very high frequency radios compass deviation and 180 81 installation 183 86 191 power supply 182 Volta Alessandro 5 voltage 6 9 checking on AC circuits 167 69 DC accessory requirements 136 loaded 92 measuring 30 31 32 33 no load 92 open circuit test 84 to outboard engine solenoid 134 35 reference 92 ripple voltage test 93 94 to starter motor circuits 128 30 129 to starter motor solenoid 127 three step voltage test 92 93 voltage drop 3 8 9 acceptable 32 AC vs DC 157 160 battery combiners and 82 conductor sizes for 43 44 45 for DC accessories 137 inverters and 173 74 maximum 32 measuring 31 34 35 128 130 32 and wire size 43 44 45 137 144 voltage regulators 87 voltmeters See also multimeters to check outboard engine starter motor circuit 128 29 for open circuit voltage test 84 voltmeters console mounted 149 152 153 volts 5 6 7 8 Volvo Penta alternators 88 89 starter motor circuit 124 Ww water spray test 115 116 Watt
245. gines the ignition control module does the switching and it may have several other functions as well depend ing on the manufacturer Ignition Coil The ignition coil uses the principle of magnetic in duction to transform 12 volt battery voltage to the 25 000 to 50 000 volts needed at the spark plugs The ignition coil is nothing more than an electrical trans former a miniaturized version of the transformers you see hanging from utility poles all over the world Transformers use two coils wound around opposite sides of a doughnut shaped iron core Running 12 volt battery power through the first coil called the primary or low voltage side induces up to 50 000 volts of power in the second coil called the secondary or high voltage side As you already know from your previous reading all wires that have electrical current flowing through them are surrounded by a magnetic field The higher the current the stronger the magnet ism If a very long thin wire is coiled around a metal lic core the strength of the magnetism is increased If a magnet is moved close to a coil of wire electrical current is induced in that coil of wire just as with the alternator field windings discussed in chapter 6 By in creasing the number of windings in the coil we in crease the amount of voltage Conversely if we reduce the number of windings we reduce the voltage This induced voltage is how step up and step down trans formers work An ignition
246. h also apply to the ignition switch Essentially you re testing for battery voltage at the switch and for continuity to the solenoid This can be done outside the remote control unit up to the main plug assem bly on the control unit If the wiring harness con necting the engine to the remote control unit is in good condition which can be checked visually by tracing it from the engine up under the coaming of the boat to the control unit problems are probably within the remote control unit All manufacturers provide good functional de scriptions of each terminal in the wiring harness plug and all provide a test sequence to verify continuity between the terminals on this plug with the ignition switch in different positions However a good quick check of these terminals can also be made using your multimeter 7 Fig 8 8 Checking the wiring harness for continuity between the remote control and the engine In this picture I ve discon nected the plug at the back of the ignition switch and at the engine and am using my ohmmeter to check for breaks in the wiring harness 134 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS First verify that you have 12 volts at the ignition switch Use your wiring diagram to identify the power lead from the engine to the main plug on the engine side of the circuit This wire is usually fed by a jumper lead that comes from the starter motor so lenoid or from a junction box bolted to the si
247. he on position and they give no visual clues as to their con dition this is especially true of the trip free breakers required on boats Fortunately it s easy to test circuit breakers and fuses using your multimeter Testing Fuses First be sure the boat s battery master switch is turned on Now set your meter to the appropriate DC voltage and attach the black probe to the DC neg ative bus on the back of your distribution panel or to any good ground Touch the probe of your red lead to the positive side of the fuse holder and take a reading of your battery voltage If you don t get a reading you have a problem in the feed to the fuse from the positive bus bar If you do get a reading of battery voltage move your red probe to the terminal at the other end of the fuse and see if you get the same reading on your meter If the reading is the same as the battery voltage the fuse is working If you don t get a reading the fuse is blown and needs to be re placed If you get a reading but it s lower than the battery voltage you have a voltage drop that s proba bly caused by a corroded fuse holder Remove the fuse and clean it and the holder Replace the fuse and measure again The reading should be the same on both sides of the fuse Testing Circuit Breakers To check for electrical continuity through a circuit breaker first switch the breaker on and make sure that the terminals are clean and tight With one me ter lead attached
248. he information you re after An encouraging beep from your meter will give you that assurance Adequate Amperage One essential difference among multimeters is in their capability to read amperage on the DC scale on a magnitude normally encountered in marine electronics Many expensive meters are capable of reading amperage in tiny fractions of an amp Some of these will read in milliamps 1 milliamp 1 1 000 of an amp but will balk at reading anything over an amp Most marine electrical gear however oper ates at between half an amp 500 milliamps and about 8 amps so it s important that your meter be able to read in this range I consider the amperage reading capability of a multimeter to be extremely high on the list of essen tial features Circuit breakers and fuses are both rated by amps and you need the capability of checking them Selecting the correct wire gauge for a new piece of equipment will involve an accurate measurement of both amps and volts Excessive amperage in an un dersized improperly protected circuit is what burns boats to the waterline 27 28 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS For most of the electrical components on which you ll be working a meter that reads to 10 amps will do the job However there are certain items on some boats that will require a meter that reads much higher amperage Anchor winches starter motors and alternators all require a meter that measures in the hundreds of am
249. he days of the massive black case with gooey sealer and exposed lead cell connecting bars are fading into history Many of the heavy duty commer cial batteries are still constructed in the traditional manner but even here things are changing fast We now have low maintenance no maintenance cranking deep cycle gel cell AGM absorbed glass mat standard automotive and even special golf cart batteries Which is just the right choice for you and for your boat Well that depends on what you re going to do with the battery once you buy it Many boats today will have at least two types of batteries on board and some will have more than that Fig 5 1 A typical 12 volt battery To start we can eliminate the standard automo tive battery from all but incidental marine applica tions These batteries might look just like their marine counterparts but they are very different Automotive batteries even the so called heavy duty ones are lightly constructed with thin plates hung on fragile grids even the cases are thin plastic This is because your automobile just doesn t need a big heavy bat tery Your boat however does need a big heavy bat tery and car batteries wouldn t last very long in the marine environment Marine batteries must stand up to the vibration and deep states of discharge com mon on boats and they must be able to withstand lev els of neglect and abuse to which you would never subject your car batt
250. he entire boat It s easy to mess up here and have the outlet still work but you could possibly have introduced reverse polarity to that outlet that will not be detected by your AC panel mounted reverse polarity indicator On a boat all AC connections must be enclosed in a protective box I ve seen outlets installed on bulkheads with the back side of the outlet exposed to the inside of a cabinet or hanging locker One metal coat hanger or soup pot sliding into the back of the outlet into contact with the terminals is all it would take to create an instant short circuit The readily available and quite inexpensive plastic outlet boxes used in residential wiring are perfect for this purpose They ll last forever they can be easily in stalled from the back of the assembly sometimes without even removing the outlet and they prevent any short circuits or shock hazard Figures 11 7a and 11 7b show a typical three pronged outlet and indicate which color conductor should be servicing each prong Shore Power Cable Connector Shore Connection Shore Power Cable e Power Inlet Electrically insulated from the boat if isolator is installed Main Shore Power Disconnect e Circuit Breaker 120 VAC Grounding els 4 Type Receptacle lt Pam 1 X d 2 Pole 3 Wire Grounding Type Plugs amp Receptacles Grounding Conductor Green
251. he following descriptions the dif ferences between the basic types of battery chargers are significant Ferro Resonant Battery Chargers Ferro resonant battery chargers are deceptively sim ple devices nothing more than a simple transformer a ferro resonant transformer that converts 120 volt alternating current into 12 volt alternating current and a rectifier that converts the alternating current into direct current The basic units the simple house hold battery chargers sold at the auto parts store work just fine for getting the car started on a cold morning or for a quick charge on a dead battery but they have no place on your boat Ferro resonant chargers designed for use on boats are a little more complex than the basic units They incorporate some elaborate circuitry that will gradu ally taper the charging current to roughly match the demands of your battery The better ferro resonant chargers work fine on wet cell batteries but even the best don t do a very good job with the new gel cell and AGM batteries In fact many of the problems associ ated with premature battery failure such as a rotten egg odor and boiling of battery electrolyte the result of constant overcharging are often caused by the use of the ferro resonant chargers Unfortunately some of the largest producers of powerboats such as Bay liner and Sea Ray still install ferro resonant chargers in their boats because they are considerably less ex pensive
252. he temperature sur rounding the charger itself may not if it s mounted as it should be in a well ventilated location The best chargers today use the third type of tem perature compensation a temperature sensor that s mounted to either the side of the battery or inside the battery box Always look for this feature when you upgrade your battery charger Testing Battery Chargers Testing your shore powered battery charger to deter mine if it s functioning is easy With the charger turned off do an open circuit voltage test as de scribed in chapter 5 at the battery the charger is con nected to Turn the charger on and observe your voltage reading at the battery If the charger is func tioning you ll get a reading of at least 0 5 volt greater than the open circuit voltage If it s not working properly the charger may have a blown fuse The fuse is usually accessible on the outside case of the charger and is easily changed One charger I ve worked with however made by Statpower locates the fuse inside the charger housing necessitating partial disassembly of the unit to check the fuse Check the manual for the charger on your boat to determine the exact location of the fuse If the fuse checks out you may have a problem with the shore power side of the circuit supplying the charger Remember Alternating current can kill you Before starting to troubleshoot the battery charger circuit be sure to read chapter 11 of this boo
253. he timing relative to the position of the carburetor throttle In addition the CDI unit electronically controls the discharge of the built in capacitor and sends this voltage to the ap propriate primary side of the ignition coil for the cor rect cylinder The CDI unit may also have electronic circuits within it to limit engine speed to prevent over revving and some even have a circuit that reduces Maintaining Marine Ignition Systems engine rpm if for any reason the engine begins to run too hot Some of the larger engines may automati cally advance ignition timing during initial start up and when the engine is running at temperatures of less than approximately 100 degrees Manufacturers often use one CDI unit for each bank on V type power heads One module will con trol the odd numbered cylinders and the other will service the even numbered cylinders Once the volt age leaves the CDI unit it s sent to the high tension coil which is similar in design to the inboard system type already discussed Here the voltage is stepped up to anywhere between 15 000 and 40 000 volts the voltage that s required to jump the air gap in the spark plugs The high tension ignition coil has two sides primary and secondary just as it does on an inboard system It s really two coils combined into one neat compact case Figure 7 10 shows the in ternal construction ofa typical ignition coil with pri mary and secondary windings The coil works by usi
254. hensive wiring diagram you still don t know what all those multicolored wires in back of the distribution panel do This brings us to circuit identification a procedure that s a little dif ferent than wire identification Circuit Identification Circuit identification will help you to determine the specific function of each wire in back of your switch or circuit breaker panel which for consistency let s call the distribution panel or any wire on the boat for that matter There are several accepted methods for identifying circuits but unless the manufacturer of your boat was unusually considerate you ll have to come up with a system and install it yourself The technique is called wire chasing in electro speak and it simply involves following a specific wire from one end to the other and placing some means of identification on the wire as you go First learn to concentrate on the circuit in ques tion forget about all those other wires for the time being Fortunately circuit identification is one of the easiest ways to become familiar with the details of your system Here are a few methods you can use Numbered Labels On the off chance the manufacturer of your boat was unusually meticulous and provided circuit identifica tion this is the method they probably used to do it Numbered circuit ID labels come in pads available in any electrical supply house They are simply clear plas tic peel and stick labels with whit
255. her pure cranking batteries or pure deep cycle batteries Pre viously owners of these borderline boats were forced to choose between two imperfect options We now have batteries advertised as combination cranking deep cycle units that are a perfect solution for the weekend powerboater who occasionally spends the night camping or fishing at anchor and spends the rest ofthe time at the dock plugged into shore power Combination batteries offer a compromise in performance They won t be as capable of sustaining repeated deep discharging and recharging as a true deep cycle battery but they will be fine for occasional deep cycle use and more than adequate for starting your engine As with any battery a combination unit must be sized to fit your specific needs and the needs of your boat Some Specific Recommendations Let s sum up all this various information and make a few specific recommendations for the right battery to put into your boat gt Small open boats with manual start engines min imal electrical gear and possibly an electric trolling motor need one or two deep cycle batteries matched to amperage needs gt Personal watercraft need a single AGM or gel cell battery large enough to meet engine cranking re quirements gt Outboard center console boats need dual combi nation batteries with one for starting and one to run the electronic systems pm Water ski boats need a cranking battery or a com bination unit of a s
256. here If all looks well ensure that the tang that s attached to the rotor and follows the center contact inside the distributor cap is bent to allow for 4 inch 6 mm clearance as shown in figure 7 7 Ignition Sensor Next take a close look at the ignition sensor It s best to use a magnifying glass for this because you ll be Fig 7 7 Rotor contact bent to allow 4 inch clearance looking for hairline cracks called jumpers in the metal connecting links on the sensor If you find any cracks replace the sensor Figure 7 8 shows the sen sor and points out the jumpers in question If the sensor does require replacement it s easily removed at this point by backing out the two retain ing screws indicated in figure 7 9 When you reassemble the distributor you ll need some Loctite 271 which is available at any good auto parts store Apply several drops to the inside of the rotor at the positioning key and put several drops in the keyway on the distributor shaft where the key fits into the rotor Immediately reinstall the rotor Do Maintaining Marine Ignition Systems not under any circumstances use a silicone based sealer on the inside of the distributor to repair the cap gasket for example As they cure most silicone sealers give off acidic vapor that can cause corrosion on the ignition contact points and conductors inside the distributor MerCruiser Thunderbolt V System The Thunderbolt V system of
257. hree and sometimes four distinct phases for revitalizing your batteries 1 The bulk phase The first phase of the battery charging cycle is known as the bulk phase This is where most of the charging occurs A discharged battery can accept a higher rate of charge up to about 70 to 75 percent of the total charge in the initial stages of charging than it can in the final stages Typical charge rates during the bulk phase are 20 to 40 97 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS percent of the battery s capacity in amperes with a voltage of about 14 4 volts Gel cells will charge at about 14 1 volts When the bat tery is 75 percent charged the smart charger automatically switches to the acceptance phase of the charge cycle 2 The acceptance phase The second phase of the battery charging cycle is known as the accep tance or absorption phase During this phase the voltage is maintained at 14 4 volts for wet cell and AGM batteries and at 14 1 volts for a gel cell The charging amperage is grad ually reduced until a rate of 4 percent of the battery s capacity is achieved Thus the accep tance phase for a 100 amp hour battery ends when the charging amperage the battery will accept reduces to 4 amps The smart charger automatically switches to the float phase 3 The float phase The final phase of a normal charging cycle is known as the float or finish phase during which the smart charger reduces the voltage to 13 3 vo
258. hrough these drawings one at a time and make sure you have at least a tentative understanding of what you have done Convert any of your rough sketches of components to the proper symbols as shown in figure 2 1 if you can but the important thing is that you know what your figures represent If you find one or two that are still confusing just retrace the 23 24 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS wires on your boat it will be much easier the second time around until you understand what you have written down It s now time to put it all together in a final drawing The Final Draft If you have done a good job with your rough draft the final draft is optional A well done rough drawing is often more than adequate for use as a working wiring diagram and more than enough for most working electricians Any professional electrician working on your boat will love you forever for your efforts in drawing up the rough draft just because you have made his or her life so much easier There is also an advantage to keeping all your subsystems on sep arate sheets because as you make additions and changes to your boat you can redraw each subsystem as it becomes necessary If however you re the fastidious type and would like a more professional and finished look for your di agram there are several ways to accomplish this The easiest approach is to buy an electrical engineer s stencil at any well equipped art supply store and use i
259. ic Equipment a serious amount of magnetic interference Regard less you should always check to be sure Note Never key the mike on a VHF radio as part of this test Keying the mike on a VHF radio with the an tenna disconnected can damage the transmitter in the radio Figure 12 1 shows the compass deviation being checked with a set of alligator clip jumper leads that temporarily connect the device to a battery These jumpers are part of your basic tool kit from chapter 1 Radio Frequency Interference RFI Another thing to consider when installing certain electrical devices such as battery chargers and in verters on board is what is known as radio frequency interference RFI Things like alternators and faulty ignition systems can also emit RFI You may have heard one of the effects of RFI caused by faults like a cracked distributor cap or a bad spark plug wire as static over an AM FM radio Ignition induced RFI changes pitch in direct proportion to engine rpm Fig 12 1 Checking compass deviation with a temporary hookup to an electronic instrument 181 182 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS An easy way to isolate RFI is with a small portable transistor radio Simply tune the radio between two AM stations FM stations don t work as well and you re ready to go Turn on the electrical compo nent you want to check and listen for a loud hum from the radio Move the radio alternately c
260. ies 68 nonmotor circuits 55 Ohm Georg Simon 5 ohmmeters See also multimeters checking internal battery of 38 interpreting 38 39 testing spark plug wire 115 ohms 5 6 7 8 Ohm s law 5 8 7 oil pressure gauges problems 148 troubleshooting 152 154 155 wiring diagram 153 oil pressure sending unit 152 154 155 OMC alternators 81 88 89 starter motor circuit 124 100 150 percent rule 54 55 56 open circuits 9 open circuit voltage test 84 optical timing systems 122 oscilloscopes 157 outboard and PWC ignition sys tems 103 4 105 CDI system 110 12 engine stop control 112 INDEX testing 112 20 121 outboard engine charging sys tems 94 96 95 Outboard Engines Maintenance Troubleshooting and Repair Sherman 135 148 outboard engine starter circuits See starter motor circuits outlets AC connections 164 165 checking voltage at 167 168 GFCI 166 67 overcharging batteries 76 86 89 97 overcurrent protection AC 162 63 164 165 174 standards 57 58 overload OL readings 38 39 170 panelboards See distribution panels panel feed wire 138 162 parallel circuits 2 4 personal watercraft PWC and outboard ignition systems 103 4 105 CDI system 110 12 engine stop control 112 testing 112 20 121 pie formula 6 7 8 pinging 106 109 10 PL 259 coax connectors 185 86 polarity 156 159 checking on AC circuits 167 70 polarity sensitive electronic equipment
261. if you have a set of meter leads that use alligator clips in place of spike probes It s also unlikely that your leads are long enough to reach from the distribution panel to the light fix ture so you ll need a jumper wire Any piece of wire that is the correct size and length will do fine Just add an insulated alligator clip to each end and you re in business Now clip one end of your jumper wire to the wire you disconnected at the distribution panel and the other end to either meter lead Clip the other meter lead to the wire you disconnected at the light fix ture and listen for the beep If you don t hear a 37 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS beep you either have the meter connected improp erly or you don t have continuity If you don t have a continuity alarm check for a reading on the me ter Any reading but OL overload is fine Zero means no resistance at all OL means infinite resis tance and a break in the circuit A common mistake made by beginners and more than a few of us pros is to pinch the probes of the meter leads onto the ends of the wire with bare fin gers If you try this and there is a lack of continuity in the wire the current from the meter can take a de tour through your body and your meter will beep and show continuity when none exists Any time you re using your meter it s best not to touch the probes but when you re checking continuity or resistance it s Fig 3 16 Chec
262. ilar arrangement with the isolator Figure 5 14 shows a twin engine installation with dual battery switches and an isolator Battery Combiners Relative newcomers to battery interconnectivity are devices known as battery combiners These devices available from all major marine equipment vendors offer significant advantages over diode type battery isolators Unlike conventional isolators combiners don t suffer from the inherent voltage drop caused by diodes which results in more precise battery charging control These new combiners incorporate voltage sensing circuitry that automatically connects or disconnects multiple batteries combined based on whether they are charging or discharging You can think of these combiners as electronic devices with some built in intelligence Diode isolators do not have such intelligence which requires you to make some compromises especially when you are combin ing different kinds of batteries such as a cranking bat tery and a deep cycle battery Cranking batteries recharge much more quickly than deep cycle batter ies In the old days this meant that when combining batteries cranking batteries were typically over charged while deep cycle batteries continued to charge The Blue Sea unit shown in figure 5 15a over comes that problem by just turning off the charge to the cranking battery in the circuit once the battery reaches a prescribed voltage level Additionally the new combiners allow tempor
263. ill be Type 3 tinned cop per wire you must decide which size Important consid erations here are the length of the wire the voltage usually 12 volts but if your boat is over 35 feet long you might have a 24 volt system and the amperage the circuit is ex pected to carry sometimes called ampacity This infor mation is usually supplied by manufacturers of the equipment you intend to install on the cir cuit If it isn t contained in the 42 Fig 4 1 Table XII from the ABYC electrical standards section E 11 comparing wire types and stranding ABYC diameter than the equivalent SAE designation Stick to AWG rated wires prefereably those marked boat cable on the insulation As the wire gauge numbers get smaller the wire gets progressively bigger in diameter and the mini mum circular cross sectional area of the wire indi cated by circular mils CM gets larger Next the chart shows the minimum number of strands for both Type 2 and Type 3 wire The finer the strands the more strands there are in a wire of a given size and the more flexible the wire will be It s easy to identify the two wire types because Type 3 wire has a lot more strands than Type 2 For example an AWG instruction manual or printed on the side of the equipment itself you may have to perform the following test to determine what these values are To test for amperage connect the equipment you want to test to your boat s b
264. ime the engine turns over regardless of whether it starts or not Figure 7 5 on page 108 shows the cap orienta tion with the position of the tab indicated Once you have the cap off clean it thoroughly with warm soap and water and dry it use com pressed air if you have a supply Next carefully in spect the cap looking for excessive burning or corrosion Check the center contact for deteriora tion Minor corrosion which is not unusual can be removed with the tip of a straight bladed screw driver Look for any signs of carbon tracking on both the inside and outside of the distributor cap Carbon tracks will show up as random fine lines etched into 107 108 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Fig 7 5 Distributor cap showing positioning tab Make sure this tab is lined up with its corresponding groove in the distributor housing when reinstalling the cap the surface of the plastic These tracks often mis taken for cracks are actually secondary voltage leaks short circuiting the intended path The spark actually etches a carbon groove into the surface of the cap Carbon tracks are most often caused by dirt and oil accumulation on the cap If there are any signs of car bon tracking the cap will have to be replaced Fig ure 7 6 shows a carbon track on the inside of a four cylinder distributor cap Next inspect the rotor sensor wheel located un der the distributor cap Again you ll be looking for co
265. in use A Fig 4 27 Ratcheting crimper in use Fig 4 28 The correct amount of wire protrusion through the barrel of the connector Wire and Circuit Protection Standards and Repair Procedures Make sure the crimper is in proper orientation with the terminal For all but the butt type connec tor the handles of the crimping tool must be in the same plane as the ring or blade of the terminal as shown in figure 4 29 For butt connectors this really Fig 4 29 Orientation of the plier jaws with the connector to make a proper crimp doesn t matter but be sure both crimps align in the same plane Always test your crimps by pulling on the wire hard enough to be sure they ll hold The newest variety of crimp terminals comes with heat shrink casings preinstalled After you crimp the terminal to the wire heat the terminal with a heat gun and the insulation will shrink tight around the terminal and seal it against moisture This is a supe rior method of applying a terminal to a wire but these terminals cost approximately a dollar each at this time When splicing a group of wires in a harness it s a good idea to stagger the butt connectors so you don t end up with a bunch of them in one spot Figure 4 30 illustrates what can happen A better approach is shown in figure 4 31 At some point you may find yourself having to re pair or replace a gang plug There are many types of
266. ing diagram for the boat then lists the numbers and iden tifies them The standard also allows for color sub stitution as long as a wiring diagram is supplied to identify the wires positively If you own one of these older boats or a new one that doesn t comply with the ABYC color coding standard the only answer is to go through the entire electrical system and write down the color and func tion of each wire This isn t as hard as it sounds and I show you how to do it at the end of this chapter Fortunately compliance with the standard is now nearly universal and the odds are that if you re buy ing a new boat both the boatbuilder and the engine manufacturer will have complied This is good news Working with Wiring Diagrams gt A Note on Engine maker Compliance and the ABYC Color Code It s important to note that the ABYC standards are recommendations only and should not be confused with the National Electric Code NEC the mandatory safety standards for land based electrical installations devel oped and published by the National Fire Protection Association NFPA Mercury Marine is one of the few engine manufacturers that actually fol lows the ABYC recommended color codes But since all engine makers provide comprehensive wiring diagrams with their products they are still compliant with ABYC standards of course but even if your wiring system is in com pliance with the ABYC recommendations and you have a compre
267. ion issue comes up The inverter location checklist that fol lows highlights these key points p gt Inverters must be located in a compartment sepa rate from gasoline engines and tanks p gt Inverters must be located as close as possible to the batteries p gt Inverters must be securely mounted to a bulkhead and through bolted with adequate backing wash ers p gt Inverters must be located in a well ventilated loca tion to allow for cooling of the unit and to allow any hydrogen gas that builds up as part of battery charging to escape Further considerations once a suitable spot for the inverter has been decided upon have to do with proper standard with the units but are available as an option from the inverter manufacturers These fuses and holders are rated for extremely high amperage and are generally described as class T fuses As for the location of these fuses the 7 40 72 inch rule applies Refer back to chapter 4 if you need to refresh your memory Figure 11 20 shows this fuse installed in the DC positive feed to an inverter As for system monitoring to comply with ABYC recommendations your inverter will need to have some form of indication installed in or very near your existing AC panel or if none exists as yet near the existing DC panel to let folks know that an in verter is installed on board and when it s on line This can be accomplished via the installation of a voltmeter indicator light or
268. ional distributor ignition systems on gas engines to computer controlled DIS distributorless ignition systems Flat serpentine drive belts used to run engine driven alternators are now the norm rather than an anomaly so some ad ditional information has been provided relative to the maintenance of these very important drive belts Next we are now seeing the broad use of net worked engine con trol systems from such companies as Mercury Marine with its SmartCraft system and Teleflex with a similar system The use of these systems will ultimately sim plify things but for now it looks daunting to the untrained eye Now we re distribut ing data from one point to another in addition to basic electrical distribution We ll discuss these changes in chapter 10 Additionally we re just beginning to see entire electrical systems that are reduced to many fewer wires from such companies as Paneltronics with its PowerSign System and Capi2 s three wire system These systems go beyond the scope of this book but my book Advanced Marine Electrics and Electronics Troubleshooting covers them in more detail Finally we ve seen the increased use of alter native energy systems specifically solar panels on cruising powerboats The need to know informa tion relative to these systems is provided in this second edition Copyright O 2000 2007 by Edwin R Sherman Click here for terms of use Introduction This book has been evol
269. ions for these tests ter to the high ohms scale if it s not self scaling and touch the free probe to the metal timing plate to which the lead harness is se cured Any reading on the meter other than OL indicates a short to ground The flywheel must be re moved to correct the problem which is either frayed or melted insulation or a bad charge coil To test the continuity of the trigger coil follow the above procedure for the charge coil tests only adjust your meter to a much lower resistance between 15 and 50 ohms is usually about right To test for a short to ground in the coil lead set the meter on the same high scale as for the charge coil short test If your en gine is equipped with more than one trigger coil test them all Figure 7 17 shows these tests and the point at which the wiring harness emerges from under the fly wheel It also shows the timing plate assembly To test for voltage from these coils you need the DVA adapter shown in figure 7 18 and available through outboard engine dealers This adapter can be used with any system of this type and converts the AC voltage from your charge and trigger coils to a DC voltage your multimeter can easily read Suffi cient readings from 1 to 9 volts will not only attest to the performance of the coils but also verify that the magnets under the flywheel have enough magnetism As you know voltage increases in direct proportion to the speed of the engine and the streng
270. ircuits you re working with Be diligent the better vendors stock the common colors and they can order other colors for you They may ask you to order an entire roll though which may not be practical in some cases If you can t find the colors you want use the alternative methods for labeling wires I discussed in chapter 4 Fuses and Circuit Breakers Once your wiring has been selected you must select the appropriate fuse or circuit breaker for your new circuit This can be a little tricky Remember that the circuit protection may be rated to as much as 150 percent of the amperage handling capacity of the smallest wire in the circuit This means that if you connect a new accessory with a continuous draw of 5 amps you would use a fuse or breaker rated not necessarily at 150 percent of 5 amps 7 5 amps but rather at 150 percent of the wiring capacity Let s take a closer look at this problem The wire must be rated at the engine room spec ification if any length of the wire goes through this space regardless of length Keep in mind that the fol lowing ampacity figures are for wire with an insula tion rating of 105 C which is the most common type found in marine supply houses If your new 12 volt accessory were going to be mounted 10 feet away from your boat s main distri bution panel measured along the wiring you would have a total run of 20 feet Using the 3 percent 137 138 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS
271. ire 1 7 amps Always round up so in this case the amperage requirements would be 2 amps 3 Use the table of wire gauges in figure 4 3 on page 44 for acceptable voltage drop and length of wire run If the amperage requirements are less than the minimum specified on the table use the gauge indicated for the minimum value 5 amps In any event never use wire smaller than 16 AWG when adding anything to your boat no matter how little current is drawn by the equip ment you re installing Wire smaller than 16 AWG is only used for electronic control circuits and small connecting links on the back of instru ment panels and the like 4 Select the switch or circuit breaker on the distrib ution panel you ll be using to feed this new circuit 5 Determine that the amperage rating of the fuse or circuit breaker is appropriate for the total of all circuits or loads being fed by that breaker For example In this case you may already be servic ing several cabin lights in addition to the one you re adding Total circuit protection at the panel must cover the amperage of all the lights on any given circuit The fuse or circuit breaker must not be rated at more than 150 percent of the ampacity of the smallest wire used which 139 POWERBOATER s GUIDE TO ELECTRICAL SYSTEMS could well be the pigtail on the back of the fix ture not the feed wire B Check the total load on the distribution panel and ifthe wire and circuit protection on
272. ire run FLEXIBLE CORDS DESCRIPTION Hard service cord oil resistant 60 C 140 F 75 C 167 F amp higher compound Hard service cord thermoplastic 60 C 140 F 75 C 167 F amp higher O STOW Hard service cord oil resistant 60 C 140 F 75 C 167 F amp higher SEO SEOW thermoplastic Junior hard service cord oil resistant compound Junior hard service cord thermoplastic 60 C 140 F 75 C 167 F amp higher Junior hard service cord oil resistant 60 C 140 F 75 C 167 F amp higher thermoplastic All wire used in DC circuitry should have a mini mum rating of 50 volts stamped on the insulation Most quality wire will have the AWG gauge embossed on the insulation as well In general wire sold as marine grade at the major supply houses will have a 105 C rating for the insulation but it pays to check Fuses and Circuit Breakers Depending upon when your boat was built and who built it you may have any combination of circuit breakers or fuses of different types used as circuit protection devices All such devices used on pleasure boats work on one of three basic principles two of which depend on heat generated by resistance and a third that works on current induced magnetism Since fuses are easier than circuit breakers to under stand let s take them first AVAILABLE INSULATION TEMPERATURE RATING 60 C 140 F 75 C 167 F amp high
273. irectly to the two largest terminals on the solenoid A reading here in excess of 0 2 volt indicates a fault inside the solenoid and it will have to be replaced Next connect the voltmeter as shown in figure 8 7c with one lead to the terminal on the output side Tracing and Repairing Starter Motor Circuits Battery Cable Size Here are a few guidelines for sizing battery cables For engines 15 horsepower and under with a distance of less than 10 feet 3 meters fo the battery 10 AWG cable is usually adequate T For runs of 10 to 15 feet 3 to 5 meters use 8 AWG g For runs of 16 to 20 feet 5 to 7 meters use 6 AWG z On engines in the 20 to 30 horsepower range use 6 AWG 4 AWG or 3 AWG respectively for the same cable runs z On the larger engines V4 and V6 use 4 AWG 2 AWG and 1 AWG respectively of the solenoid and the other to the large positive ter minal on the starter motor While cranking the engine your voltage reading should not exceed 0 2 volt If it does the connection at the solenoid is bad or as with the battery cables the wire connecting the solenoid to the starter motor is too small This wire should be the same size as the main battery cables A too small cable would only be a problem if someone changed the cable before you Factory wiring is care fully engineered for size and is never too small Diffi culties are caused when improper repairs are made Start
274. is cannot be emphasized enough A battery Circuit Breaker Starter Motor Solenoid Starter Slave Solenoid 90 Amp Batter y Fuse Fig 8 2 Typical MerCruiser starter motor circuit diagram weakened by a sticking bilge pump float switch or a light left on while the boat was unattended for an ex tended period is a common cause of an engine failing to start Always be certain your battery is charged to at least 70 percent of its capacity before you assume that you have starter motor problems If your boat doesn t have a voltmeter to help you determine battery charge use your multimeter and take a direct reading of open circuit voltage at the battery using the Open Circut Voltage versus State of Charge table in the Open Circuit Voltage Test sec tion on page 84 If your battery is low you will of course have to find out why and the steps outlined in chapter 5 will help you to isolate the cause Troubleshooting Starter Motor Circuits Once you confirm that the batteries are not the cause of your starter problems you should begin Tracing and Repairing Starter Motor Circuits troubleshooting Have the workshop manual close at hand so you can identify all the circuit compo nents for your boat As a first step look at all wiring and connections to all starter circuit parts Tighten any loose parts and terminals and clean any corroded terminals Don t forget to check the fuses and circuit breake
275. is sure to cause damage to the area around the con nection read melted switches and plug connections Figure 1 7 illustrates Mr Ohm s formula Ohm s Law No you don t have to worry about going to jail for breaking Ohm s law In fact you can t break it not without a nuclear particle accelerator that costs many millions of dollars because it is for all practical pur poses inviolate you couldn t break it if you tried Sim ply stated Ohm s law is a mathematical formula we can use to calculate any one of the values we mention above as long as we know the value of any two of the first three For example if we know the amperage and resistance for a circuit we can easily calculate the voltage or if we know the voltage and amperage Ohm s law gives us the resistance Once we know the amperage and the voltage we can calculate the wattage using a simple lit tle formula called the pie formula that we will get to in a moment Working with the Numbers It s important to note here that various versions of the following formulas exist assigning different letter designations to the elements of the formula E for volts or sometimes watts for example the letter I is often used to designate amperage as well The point is that it really doesn t matter what letter you use as long as you know which value it s assigned to For our purposes we ll keep it simple and use V for volts A for amps W for watts and R fo
276. ists or not You can do one with your mul timeter the other will require a special LED test tool Ripple Voltage Test Think of ripple voltage as a tiny amount of alternating current that has escaped past the bridge rectifier and has imposed itself on the direct current charging your battery A small amount of ripple current is normal but if you find a significant amount it indicates a problem with one or more or the alternator diodes Fig 6 9 LED charging system tester connected Simple two wire connection simply follow the instructions on the tester Actron makes a similar tool for about 25 94 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Fig 6 10 AC ripple voltage test Your black meter lead should be connected to a known good ground and the red lead to the B output lead on the back of your alternator Remember to make sure that your meter is set to the AC volt scale If you have one of the LED testers shown in figure 6 9 alternator testing is a one step procedure The tester has red and black leads and probes just like your multimeter Attach the red probe to the B ter minal at the back of the alternator and the black probe to a nearby ground one of the alternator mounting bolts will do and start the engine Ob serve the LEDs on the meter Any lights flashing or constantly lit indicate a problem with either the al ternator or the voltage regulator assuming the al ternator is getting excitation voltage
277. ite Figs 11 7a b Standard outlet for a three pronged plug showing which socket does what and the color of the wire going to it 165 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Ground Fault Circuit Interrupters Ground fault circuit interrupters GFCIs are a spe cialized type of circuit breaker designed to trip open whenever resistance between ground and the un grounded conductor drops below 25 000 ohms Any time current is diverted from the white wire such as through your body when you grab a hot AC wire the GFCI senses the absence of grounding current and opens the circuit hopefully in time to prevent all your friends and relatives from having to make pre mature calls to the florist Just as with home installations boats are re quired to have ground fault circuit interrupter out lets on certain branch circuits of the AC service This type of outlet is easily identified by the test and re set buttons located on the face plate Many novice electricians assume that the purpose of GFCIs is to protect the circuit or device a circuit is feeding Not so GFCIs are intended to protect people from shock not equipment GFCI protection is required in areas of the boat where excess moisture or a particular shock haz ard may exist Specifically the ABYC recommends GFCIs in heads galleys engine rooms and on deck For all practical purposes this means you may want a GFCI on every AC circuit on your boat In som
278. ithin the device In all cases it s advisable to consult the manufacturer of any electronic device you intend to install and find out about its sensitiv ity to RFI While you re at it get any recommenda tions they may have regarding separation zones and RFI suppression methods Power Supply Virtually all small boat electronic equipment avail able today requires only a positive and a negative lead to get the basic unit running Some sensitive elec tronic equipment housed in metal cases may require a chassis ground green wire in addition to the neg ative lead yellow or black wire Still other equip ment may have an additional hot lead red wire to power an internal memory This extra lead must get power at all times and must not be switched in any way If you have any doubt about how these leads should be connected refer to the installation instruc tions for the particular equipment in question Remember unlike things such as incandescent cabin lights most new electronic gear is polarity sen sitive This means if you inadvertently switch the pos itive and the negative wires when you connect them to your power source you could severely damage the equipment Most manufacturers supply a red and a black lead with their equipment indicating DC pos itive and negative although white and black wires are still widely used Always refer to the equipment in stallation instructions to be absolutely certain With the exception of V
279. ition Systems comes in two variations one with a remotely mounted ignition module located on the port side exhaust elbow and the other with the ignition mod ule mounted on the side of the distributor body Repair procedures for both variations are the same Ignition module replacement will be slightly different Service procedures for this system are not too dif ficult Besides the generic procedures already men tioned for ignition systems some specific system information follows Distributor Cap Service The distributor cap needs to be kept clean and dry MerCruiser recommends periodically removing the cap annually will be fine and giving it a thorough inspection Be sure to mark the high tension wires with tape and a marker before removing them from the cap so you can be certain they go back in the same order Loosen the four screws that hold the cap in place and carefully lift the cap off its seat on the distributor There should be a gasket between the cap and the edge of the distributor housing be careful not to damage it If it s damaged in any way it will have to be replaced This gasket is an integral part of the ig nition protection for the distributor Look closely and observe the alignment tab molded into the cap and the corresponding indent on the body of the dis tributor housing Upon reassembly make sure this tab and groove are aligned otherwise damage to the distributor cap and rotor can occur the first t
280. its 3 marine vs residential AC mate rials 162 master distribution panels 14 15 19 20 142 See also distribution panels MDL fuses 48 49 141 174 mean best timing MBT 110 mechanical gauges 147 Mercury Marine ABYC color coding and 17 alternators 81 88 89 DIS 102 DVA adapter 116 18 117 ignition sensor 109 SmartCraft 155 starter motor circuit 124 125 Thunderbolt systems 107 10 108 109 tilt stop switch testing 120 121 meter leads 34 36 37 modified square waveform 175 motor circuits 54 55 multimeters 5 11 25 analog 26 checking AC voltage at an outlet 168 charging amperage test 93 checking generator voltage and frequency 176 checking starter motor cir cuits 128 30 129 digital 26 28 38 draw test 94 inductive pickups 28 29 36 37 measuring amperage 34 36 37 measuring resistance and continuity 37 39 150 51 169 70 measuring voltage 30 31 32 33 measuring voltage drop 31 34 35 130 32 multiple 28 29 open circuit voltage test 84 outboard engine tests 115 20 121 recommended 29 30 205 206 multimeters continued ripple voltage test 94 selecting 25 30 testing neutral safety switch 132 33 testing solenoids 126 127 National Electric Code NEC 17 National Fire Protection Associ ation NFPA 17 National Marine Manufacturers Association NMMA 40 neutral safety switch 128 129 130 132 33 no load voltage 92 no maintenance batter
281. ity the latest ver sions of LCD and CRT fish finders are really outstanding The performance gains over the last 10 years with this type of equipment have been just phenome nal and prices for quality gear have actu ally gone down for even the most DC From K Electronic Equipment Ea Coaxial Cable E Fig 12 8 Overview of a complete VHF radio installation 186 advanced feature packed units But in the same vein as VHF radio perfor mance these fish finders are only as good as the information getting to and from them Think of the fish finder or depth sounder transducer as a two way antenna that must send and receive signals Rather than shooting through the air as do VHF signals these signals leave the underside of your boat bounce off the bottom of the waterway then get back to the transducer where they are translated into water depth This is how you spot ol silver sides hiding in a clump of weeds 10 feet off the port side of your boat As with your VHF installation you must consider any magnetic fields emitting from the control unit of the fish finder or depth sounder that could affect your compass This is of particular concern if you have selected a cathode ray tube CRT instead of a liquid crystal display LCD device By their nature CRT fish finders emit magnetism right through the face of the screen so be sure to check this out as de scribed earlier in this chapter
282. ize dependent upon the size of the engine and amperage requirements pm Weekend cruisers need either one cranking bat tery for the engine and a separate deep cycle bat tery for the systems or two combination units depending on amperage requirements and amp hour loads gt Long range cruisers need cranking batteries large enough to meet engine requirements and enough deep cycle capacity to meet total daily amperage requirements When you re choosing a battery for your boat and you find that you can t decide between units of two power ratings always go with the larger of the two There is seldom any trouble with a battery that s slightly too big provided that it fits into your bat tery box but one that s too small can open up a world of problems When you really need your bat tery you won t need a dead one so always err on the side of too big rather than too small Batteries for Cruisers If you re a cruiser and spend days away from the dock you need to get serious about batteries Your needs are completely different from the day tripping water skier or fisherman First you should do an electrical load survey on your boat and calculate the extent of your electricity needs while unplugged from shore power This survey will help determine how big a battery you need and establish how many amp hours you ll need in it You need a dedicated start ing battery and a separate house battery to run the equipment you ll be
283. k The best advice is to use the largest coax you can to min imize signalloss Always install a high quality lead on any antenna you buy There are three common kinds of coaxial cable available today RG 58 RG 8X and RG 8U Just as with regular wiring the signal loss is proportional to the length of wire For most small powerboats the Installing Marine Electronic Equipment wire won t be much more than 20 feet long so the loss will be minimal The table in figure 12 6 com pares the dB signal loss for a 20 and a 40 foot cable run using each ofthe cable types mentioned here No tice that the loss in dB between the RG 58 and the RG 8U cable is more than double even for a fairly short 20 foot cable run Besides the basic types coaxial cable comes in dif ferent construction configurations and these can make a difference in the long term performance of the cable Coaxial is basically a two conductor ele ment separated by a PVC insulator For best long term results the center conductor should be of tinned stranded copper The second conductor is the braided outer shield which should also be of tinned copper Many manufacturers try and save a few dol lars by using a solid single strand untinned center conductor and untinned shield This type of coax works just fine for cable TV installations at home but it s not a good choice for marine VHF installations Probably the biggest source of VHF radio problems arises out of a corrod
284. k and if you have any doubts about your ability call in a professional marine electrician to help Figure 6 13 shows a state of the art Xantrex mul tiphase smart charger It also has a manual gel cell Status Ready Charging Charging Current A el M EN ET Equalize 2 5 10 20 40 Charger Mode Bulk Absorption Bulk Absorption Float __ 13 5 fixed Battery Temperature Battery Type Cold Warm Hot N OES 14 4 13 5 ITE UFE EN LUE 112135 Bere are EIERE 151134 Bere TTE Output Volts Absorption Float Sy TRUECHARGE Multi Stage Battery Charger Fig 6 13 Xantrex 40 amp charger Battery Charging Systems wet cell or AGM selection switch a battery mounted temperature sensor and switching parame ters for different phases Solar Cells Solar panels are increasingly being used on some cruising powerboats to supplement other onboard charging systems The silent energy that solar panel arrays provide is quite appealing to many boaters and once installed solar panels are virtually maintenance free For boats that spend a lot of time at anchor away from the dock and not much time underway the 50 to 80 watts that medium sized panels provide can be the difference between keeping the batteries charged up or running them down over time There are several important points to remember about solar panels First they do get hot sitting in the sun If they get too hot their output will actu
285. ker Not only are these difficult to find at times but many are uninsulated as shown here Don t pile all your tools into this one A short circuit is sure to occur across the terminals diagram can make all the difference in the world be cause it will show how the wiring for each circuit is routed through the boat A comprehensive diagram will even indicate where any of those elusive hidden junction boxes may be located Drawing Your Own Wiring Diagram Now that you know how to chase wires and to iden tify components and devices it s time to draw up an inclusive and detailed diagram of the electrical sys tem on your boat Drawing a new diagram is easier than you think although it s time consuming If you have a large boat with a complex system it s best to divide the project up into several sessions of several hours each If you don t like the way your drawing comes out the first time don t be afraid to do it over until you get it just the way you want it Even if you have a good diagram already it isn t a bad idea to make up a new one There is no better way to learn firsthand about all the little intricacies and idiosyn crasies of your electrical system than to trace each cir cuit and write it down in a diagram Subsystems The first step in drawing your new wiring diagram is to mentally divide the electrical system into subsys tems These might logically be the charging and start ing subsystem the ignition and engine su
286. king the ohmmeter battery by touching the leads together Some meters also have a BAT indicator on the face that indicates when power from the unit s internal battery is too low critical to keep your hands away from them Whenever you re using the ohms scale on your meter the wiring you re working with must not be live The switch for the circuit must be off The ohms scale and the diode check function use a tiny amount of calibrated current from the meter s internal bat tery Even a small amount of external current can dis tort your reading or even damage the meter Failure to turn off the circuit will trip your meter s internal fuse or in the case of some inexpensive meters with out internal protection you ll burn the meter out Figure 3 16 shows an ohmmeter battery test be ing performed and what your meter s screen should indicate What Do the Numhers on My Ohmmeter Tell Me Proper interpretation of your multimeter s ohm readings is important otherwise misdiagnosis of problems can occur Unlike the direct readings on the volts and amps scales resistance values are a bit more cryptic for the newcomer to electrical testing If you re using a digital meter the letters OL on your screen stand for overload which replaces the symbol for infinity familiar to analog instrument users and is shown in figure 3 17 OL means that the resistance being read by the meter is higher than its ability to read it and usually indicates a bre
287. l If you re buying a new distribution panel to add AC to your boat be sure to get one equipped with this reverse polarity indicator Any money saved on the panel by not getting this fea ture will be false economy in the long run the inci dence of reverse polarity at marina shore power boxes is just too high Figure 11 5 on page 164 shows both a single and double pole breaker of the approved type Figures 11 6a and 11 6b illustrate how these two types of circuit breakers are wired into an AC circuit 183 184 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Basic AC Outlet Connections When installing a new AC outlet the black wire to the back of the outlet must be connected to the copper or brass colored screw terminal The white wire must be connected to the white or silver termi nal and the green wire must be connected to the green terminal You must use the captive crimp ter minals described in chapter 4 for all connections to the outlet The spring loaded press on terminals used for some residential outlets are for use with Romex solid copper wire and are never appropriate for the stranded wire you must be using if you re Fig 11 5 Single and double pole AC circuit breakers adding an outlet The screw terminal variety of household outlet is just fine as long as a proper ring eye or captive terminal as described in chapter 4 is crimped to each wire This connection scheme must be followed throughout t
288. l only be working with three colors for simple small boat AC wiring schemes Larger boats using com bined 120 240 volt systems use several additional colors for the extra legs of the circuitry that combine to make the higher voltage but these systems are used only on larger yachts and a discussion of them would go beyond the scope of this book I ll focus on only the most common single phase 120 volt 20 and 30 amp systems here The three colors used with AC in the United States are black white and green The black conduc tor is used only for the AC ungrounded positive lead Some people refer to this as the hot lead This explains the trend toward using yellow as a DC neg ative conductor in accordance with the ABYC s rec ommendations for DC systems There is an obvious risk of confusing the hot AC positive wire with the relatively inert DC negative wire which has tradi tionally been black Increasingly new boat builders are moving to the yellow DC negative wire as a means of more clearly separating the AC service from the DC service Manufacturers are now making the yel low insulated wire available in all gauges including battery cable sizes With AC the white lead should always be the neg ative grounded lead and green should be the ground ing lead which offers shock protection to the boat owner This green wire which does not normally carry current is one of the most important keys to preventing the zap you c
289. l Materials Many boatowners who want to add AC service to boats that came with only a simple DC setup as stan dard equipment head for the nearest residential elec trical supply house to get the gear for their new circuit Some people have undoubtedly seen boats that came right from the factory with this residential gear in stalled Square D switch boxes panels and breakers as well as the solid copper wire known as Romex have been used in original equipment installations by vari ous boatbuilders over the years Virtually none of this household gear meets current ABYC standards and it s definitely not recommended that household AC gear be used on board your boat In fact if your boat has household rated AC equipment one of your first orders of business should be to remove it and replace it with appropriate marine gear Remember what hap pened to the boat and licensed electrician mentioned earlier You could be next Some appropriate exceptions to this rule on marine grade versus household material are the commonly available plastic outlet boxes face plates and plug assemblies that all work just fine on boats as long as they are the all plastic type Even with these however it s best to throw away the steel screws that usually come with the equipment and substitute stainless or brass screws instead Wire for AC Most 120 volt AC circuitry on small powerboats will use 12 gauge tinned triplex boat cable for the en tire wiring
290. l mean replacing the extension harness as a unit If the wire from the control unit to the solenoid is a series of individual wires wrapped in electrical tape or plastic tie wraps you should be able to trace the harness and find the break Repair or replace the wire as required If you get a resistance reading near zero showing continuity the problem is within the remote control unit and must be fixed by your dealer Figure 8 8 shows the extension harness being tested with a multimeter Testing for neutral safety switch maladjustment is quite simple Hold the shift control lever with one hand and the ignition key with the other Hold the key in the start position and gently work the shift lever to its extremes in the neutral position Never try to shift into gear without the engine run ning you could damage to your shift mechanism If you hear the starter motor try to engage then the switch is out of adjustment or the remote control mechanism is badly worn and will need to be serviced by your dealer Don t be surprised if the control mechanism needs to be replaced due to excessive wear of the internal parts This is not un common on older units Tracing and Repairing Starter Motor Circuits Engine Ignition Switch Like the neutral safety switch most ignition switches are located inside the remote control unit described above This makes testing difficult but some of the same procedures you used to test the neutral safety switc
291. lammable hydrocarbon mixture surrounding the device when an ignition source causes an internal explosion or gt it is incapable of releasing sufficient electrical or thermal energy to ignite a hydrocarbon mixture or pm the source of ignition is hermetically sealed What this means to me and you is that on gasoline powered craft we can t have electrical stuff below decks that will ignite fuel fumes and blow up our boats To this end two important classifications need to be considered the Society of Automotive En gineers SAE designation J 1171 and the Underwrit ers Laboratory UL designation UL 1500 These specifications state that the equipment to which they apply has been tested and approved for operation in explosive atmospheres Approved equipment will have the fact that it meets the ignition protection standards written right on the specification plate Ig nition protected circuit breakers will have the state ment ign protected on the case Figure 4 13 shows this labeling on the back of a circuit breaker Make sure the components you use meet these standards These ignition protection regulations apply to all areas below decks except for accommodation spaces and well ventilated areas specified in section A 1 6 12 VOLT DC SYSTEM Fig 4 11 Screws mounting a circuit breaker in place on a typical panelboard Turn counterclockwise to remove Also make sure the main switch to the panel is turned off
292. language that s so pop ular with the technophiles and engineers who write most of our electrical manuals into plain English first so I could understand it myself and then so I could help others to understand it The very act of translating electrical technobabble into English and rewriting it into plain simple explanations got me on my way as a technical writer I first became involved with electricity as an au tomobile mechanic about 30 years ago The automo tive electrical systems of those days were fairly simple and I spent most of my time troubleshooting faulty components and repairing factory engineered wiring harnesses The wiring diagrams we had back then showed in minute detail the complete electrical sys tem for each make and model of automobile and these diagrams were readily available and easy to un derstand When I became involved with boats however things changed dramatically Before the formation of the American Boat amp Yacht Council Inc the ABYC which I talk about much more later on electrical anarchy reigned unchecked in the marine field There were no uniform standards no univer sal system of color coding and no governing body to bring order to the prevailing chaos Boatbuilders developed their own largely proprietary wiring sys tems and technicians and owners alike made changes and additions without restraint of reason or common standards Boats were often one of a kind or limited productio
293. lf destroyed generat ing enough heat to torch the boat Cabin Light while the wires remain intact 140 Fig 9 1 Simplified wiring diagram of a cabin light circuit When a motor seizes it works ame fuse 9 INC R MA TIT TTG STEF L Uu Fig 9 2 Melted bilge pump caused by installing a fuse that was overrated for the motor Notice that the wiring survived unscathed against the seized impeller and heat builds up within the motor windings As the motor heats the internal resistance increases and the current flowing through the circuit feeding the motor actually decreases You can see how this works by using Ohm s law and swap ping around some numbers If source voltage stays the same and resistance goes up amperage goes down In this case the amperage decreases to less than the rating of the fuse Both the wiring and the fuse remain intact but current will continue to flow to the motor until it destroys itself Therefore never change the fuse on a bilge pump or any other motor circuit for one with a higher amperage rating than what is recommended by the manufacturer Do you remember from chapter 4 that a slow blow fuse is often used in motor circuits These ac commodate the very high start up amperage used by electrical motors Check the manufacturer s recom mendations for all motor circuits on board your boat and have the appropriate spare fuses in your spares kit Installing just any old f
294. ll 2 Don t test immediately after charging 3 Dotestonly after the electrolyte mixes and the battery stabilizes This stabilization may take an hour or so or you can bring down what is known as the static charge by putting a load on the battery for about 15 seconds after the recharge to stabilize the battery It s still bet Batteries and Battery Systems ter to wait a while but loading the battery will give a quick stabilization Remember that the variation be tween cells is more important than the actual maxi mum specific gravity reading Most quality hydrometers have a built in ther mometer and it s not there to tell you it s time to go to the beach Specific gravity is calibrated at 80 F To compensate for readings above or below this tem perature add or subtract 4 points for each 10 your reading is below or above 80 This compensation can make the difference between condemning your battery or hanging onto it for another season Maxi mum specific gravity readings for electrolyte from a charged battery will range from 1 260 to 1 280 as compared to pure water with a specific gravity of 1 000 At a hydrometer reading of 1 260 the electrolyte Fig 5 16 Temperature compensated hydrometer in use 84 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS is 0 260 times as heavy as water because of the sul furic acid in the solution As the battery discharges the acid leaves the water and goes into the plates i
295. loser then farther away from the component you re check ing and listen for a change in the humming noise A good device to try this with for the first time is a bat tery charger I have not found one yet that did not emit some RFI it s quite normal for these devices The problem with RFI is that it can affect things like electronic compasses autopilots and Loran C systems and you ll never hear a sound However you could end up in Timbuktu instead of your favorite fishing hot spot Like the magnetism problem already discussed you ll need to ensure that a good zone of separation is kept between devices that cause RFI and devices sensitive to it For ignition systems and alternators a variety of suppression devices and filters are avail able and they are easy to install All come with sim ple instructions Check your local NAPA Auto Parts store or a good marine electronics distributor to get the parts for this job With inverters and battery chargers you can es tablish the zone of separation you need using the transistor radio method described above Simply move the radio away from the activated device in question until no noise is heard and your zone of separation will have been established If you re do ing this test with a battery charger or inverter make sure the device is not only on but also under full load or output whichever the case may be RFI emission will vary proportionally with the amount of electrical activity w
296. lt goes and isolators are mounted on a substantial heat sink to dissipate that heat This means that the isolator needs to be well ventilated or heat buildup in the heat sink will de stroy the diodes The third problem is that on some isolators the heat sink is a part of the circuit and the entire thing is hot when the battery is being charged This type of isolator must be mounted where there is no chance of any conductive material coming in con tact with it because otherwise an unfused direct short circuit can result In spite of these faults an isolator may be your best bet as an inexpensive way to keep your batteries from discharging into each other Testing Battery Isolators Testing battery isolators to determine if they are functional is a straightforward matter First mark and disconnect the cables connected to the isolator Set your multimeter to the diode check function and test for continuity in one direction through each diode and no continuity in the opposite direction Figure 5 11 shows the four steps required to test a typical isolator connected to one alternator and two batteries If you discover that you have continuity in both directions for any of the diodes in the isolator or no continuity in either direction on any of the diodes the isolator must be replaced Repairs are not practical in the field Also alternators described as one wire alternators won t work with battery isola tor
297. lts here the problem is in the starter motor and it will have to be removed for rebuilding or replacement Voltage Drop Test Another simple test that can help you to locate any bad connections undersized wires or faulty parts that could cause excessive resistance and slow crank condition in a starter circuit is called the voltage drop test This test requires a digital multimeter you ll be checking for readings of 0 3 volt or less set to the low volts scale if it isn t self scaling The meter connections and the sequence for the voltage drop test are shown in figures 8 7a d It s a good idea to get a set of the thread on alligator clip probes many multimeters now come with inter changeable probes as standard equipment available at Radio Shack and other supply houses that sell multimeters The alligator clips let you keep your probes attached to a wire or terminal while you crank the engine and take a reading eliminating the need for an extra set of hands First check the connections shown as A and B in figure 8 7a The red wire attached to connection A is from the ignition switch or starter button and pro vides power to the solenoid when the ignition switch or starter button is engaged The black wire from connection B is the ground wire to the coil within the solenoid Make sure that this ground is good Figs 8 7a d Sequence of a starter motor circuit voltage drop test being performed Excessive voltage drop at any point i
298. lts for wet cells and AGMs and 13 7 volts for gel cells Gelled elec trolyte batteries typically have a slightly higher fully charged open circuit voltage than their wet cell brothers do The float phase is more maintenance than an actual charge because it keeps the battery at a full charge without overcharging This is the big difference between the smart chargers and the ferro resonant units described earlier 4 The equalization phase The fourth phase of bat tery charging I want to discuss is really an other maintenance phase and is only used on wet cell batteries In fact use of the equaliza tion phase is quite damaging to gel cells and a waste of time on AGM batteries The equalization phase takes care of minor irregu larities in specific gravity between cells that develop as a battery ages As your battery gets older the chemical re actions inside the individual cells can vary slightly with variations in the chemicals in the water you ve added to the cells and with minor variations in the manufactur ing tolerances of the battery Lead sulfate particles will eventually begin to cling to and build up on your bat tery s cell plates As this buildup continues less and less of the battery s cell plate area is exposed to the elec trolyte and the cell s capacity is effectively reduced The equalization phase minimizes this prema ture buildup of lead sulfate by charging the battery at amperage equal to 4 percent of capaci
299. ly conductive fluid such as salt water engine negative terminal A bolt or stud on an en gine where the negative battery cable is connected ferro resonant charger Simple unit using a ferro resonant transformer to convert AC to a lower voltage before being converted to DC for charg ing batteries field winding The wire coils wound onto the ro tor inside an alternator When electrical current flows through these windings an electromagnetic field is created around the rotor assembly which induces current flow in the alternator s stator windings as the rotor spins float charge The third and final phase of battery charging Also known as the finish stage flywheel A wheel used to maintain an engine s rolling inertia between firing strokes frequency The number of complete alternations per second of alternating current fuse A conductive device designed to melt when amperage flow through it exceeds a rated amount galvanic corrosion Corrosion resulting from dissim ilar electrically connected metals being immersed in an electrolyte galvanic isolator A device installed in series with the green grounding conductor of the AC shore power cable designed to block galvanic DC current flow but permit the passage of AC if required galvanic potential A reference to where a given metal may fall on a galvanic series of metals table Anodes and zincs as they are commonly called have a higher galvanic potential than
300. m the top of the engine block is a sure indication that a problem exists and you may not be able to get the boat home without assis tance If in doubt radio for help the chance of caus ing extreme engine damage here is great and not worth the risk High Engine Temperature If excessively high engine temperature is indicated by your temperature gauge and the rise occurred sud denly you should back off the throttle to an idle and see if the temperature reading begins to drop Often it will and it s preferable to let the temperature stabi lize before shutting off the engine to scope out the problem Suddenly shutting down an overheated en gine can cause extreme shock to the engine s pistons inducing the engine to seize Once the engine has had a chance to catch its breath and stabilize somewhat shut it off and let it cool down enough so you can check the level of cooling water if you have a fresh water cooled engine Next check for a broken fan belt on the water pump If the belt is in order the most likely cause for overheating is a blocked water intake to the engine s cooling system Follow the steps outlined in your workshop man ual to determine if adequate cooling water is enter ing the system Often the problem is a piece of debris that s drawn to the intake port by the suction of the water pump In many cases stopping the boat and backing down for 10 or 20 feet will dislodge the for eign object and all will be well In
301. me resistance to electrical flow However if any current at all is flowing through a circuit you have a closed circuit and what is called continuity When do ing a continuity check you won t really care what the actual resistance might be Any resistance reading lower than infinity will indicate continuity You ll usually use a continuity check to look for an open or broken circuit Suppose for example that light in the head we were working on earlier were to suddenly stop work ing The first thing you would check is the condition of the bulb Then you would check to make sure that the switch was on and the circuit breaker or fuse was in good order Still no light It s time for a continu ity check First set up your meter to read ohms You ll now be using it as an ohmmeter The scale isn t that im portant but it s best to set non self scaling meters to the lowest scale If your meter has a continuity alarm touch the probes together and listen for the beep Also check for a zero reading on the face of the meter indicating zero ohms If you don t get a beep or if the meter doesn t read zero the internal battery for your meter is probably low and will need replac ing Next disconnect the wire for the light fixture at the distribution panel and at the light itself and con nect one probe to each end of the wire It doesn t matter which probe goes on which end Like the amperage test above the continuity test is usually much easier
302. measuring large amounts of energy but it doesn t work for the small amounts that we have to measure while working with electricity so in honor of this ancient Scot we call the electrical unit of power a watt and use a capital E to represent it Watts aren t used in the formula for Ohm s law but they are important in a corollary to Ohm s law called the pie formula because P x I E as we will soon see that we will be using to calculate the size of wires and circuit protection James Joule 1818 1889 was an English chemist credited with the discovery that heat is a form of en ergy Thus a joule is a unit of electrical energy equal to the amount of work done or heat generated by a current of 1 amp acting for 1 second against a re sistance of 1 ohm The symbol for a joule is a J and it also is not used in Ohm s law calculations Joules aren t really important for the work that we do throughout the rest of this book I wouldn t even mention them here if it weren t for the fact that the joule is gradually replacing the watt in some areas of electricity joule is also replacing calorie in the list of nutritional information on many food packages and that you ll probably run into it in your other read ing When you do hear the term you re fairly safe in assuming that 1 joule 1 watt So you can see that our foundations of electricity are named after quite an interesting international rogues gallery of electrical scientists Fig
303. ment voltage drop amperage measurement and resistance measurement These procedures are so important that we discuss each in detail Measuring voltage is the easiest so let s cover that one first Measuring Voltage To test for voltage first make sure that your meter is turned on and that the leads are inserted into the correct sockets the leads that came with your new meter probably have spike like probes on the ends battery A fully charged battery would read between 12 6 and 13 5 volts although a rare few might have alligator clips The black lead goes into the socket that s probably marked COM and the red one goes into the socket marked DCV or something similar If you do not have a self scaling meter also double check to make sure that your meter is set to the proper range 20 volts for a 12 volt system Now go to one of your boat s 12 volt batteries and touch the black probe to the negative terminal and the red probe to the posi tive terminal You should be able to read the battery voltage on your meter s digital readout If your bat Selecting and Using a Multimeter tery has a full charge this reading will be between 12 6 and 13 5 volts A negative sign in front of the voltage means that you have the probes connected backwards That s all there is to a voltage check Once you have your meter set up properly any time you touch the red probe to a hot positive terminal or bare wire and th
304. more about batteries will come later but at a minimum it will be the nominal voltage either 6 or 12 volts for each The next step is to draw in the battery cables just as they appear on your batteries For now just worry about the cables that connect the batteries to each other and ignore the others Double check to make sure you have the polarity right that all the positive and negative terminals are labeled correctly Now add to your drawing any battery isolators isolation switches or any other paraphernalia you find con nected directly to the battery If you find a mysterious component you can t identify just make a little draw ing of what it looks like and keep going You ll have plenty of time to come back and fill in the blanks when you figure out just what that mystery contraption is Once you have drawn the batteries and the di rectly connected cables move to your battery isola tion switch and draw a rough sketch of it somewhere near the middle of your diagram If your drawing becomes too messy or you run out of room simply trace the lines you want to keep onto a clean sheet of paper Get used to the idea of redrawing your work you l be doing it many times A typical switch has four positions label them on your dia gram just as they appear on your switch probably No 1 No 2 both and off Complex sys tems might have two or more of these switches Now connect the switch to the battery
305. n Copper doesn t corrode in the same way as such materials as aluminum and steel but forms a thin layer of oxidation that s highly resistant to electricity The tinning slows and reduces the forma tion of this oxide layer and greatly reduces the inci dence of problems caused by corroded wires It s also much easier to solder than untinned wire Tinned copper wire will pay off in the long run Initially it may seem a bit expensive compared to stranded copper without tinning but on a boat where corrosion is a constant battle the tinned wire will hold up far longer than would untinned wire The tinning does a great job of resisting corrosion at terminals as well as preventing oxidation from mi grating up the wire under the insulation a common problem with untinned wire Stranded copper wire is available in several types The chart in figure 4 1 on page 42 is taken from sec tion E 11 ofthe ABYC s Recommended Standards and Practices and illustrates several additional points No tice that the American Wire Gauge AWG standard is used to designate wire size You may encounter wires on your boat that carry the Society of Auto motive Engineers SAE designation Quality ma rine grade wire with an AWG size is often larger in 41 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS CONDUCTOR GAUGE 10 gauge Type 2 wire will con MINIMUM MINIMUM ACCEPTABLE ACCEPTABLE CM AREA CM AREA AWG SAE MIN
306. n additions follow with my personal step by step ap proach to installing each accessory outlined After re viewing these examples you should be ready for just about any circuit you may wish to add to your boat Installing a New Cabin Light If you re installing a conventional incandescent light or one of the newer halogen lights don t worry about polarity These light bulbs really don t care which way the electricity flows through them If you re adding a low voltage fluorescent fixture however you ll have to observe any positive or neg ative wiring indicated by the manufacturer Circuits with dimmer switches rheostats and light emitting diodes LEDs which are commonly used in instru ment lighting and are even available now as replace ments for conventional low voltage light bulbs are also sensitive to polarity Some of the companies that make light fixtures recommend the correct fuse to use and the appro priate wire gauge based on the length of the wire run If you don t have these specifications you must fig ure these numbers out for yourself The packaging should at least tell you the operating voltage of the bulb in the fixture so you ll have at least one of the needed values Also the wattage will be given with most light fixtures By using the wattage equation from chapter 1 you can easily calculate the amperage by dividing the wattage by the voltage The result will be the amperage the fixture will need For example
307. n and customers frequently or dered extra or specialized equipment added after the boat had been built and the electrical wiring in stalled Many entire electrical systems were created by self trained technicians who had even less experi ence in designing reliable and safe marine systems than I myself had at the time Problems with these do it yourself electrical systems were many and fre quently I found myself reengineering work that had been improperly poorly and sometimes dangerously installed Wiring diagrams when they were available at all which wasn t often were rudimentary and of ten inaccurate to the point of being useless Uniform color coding of wiring was nonexistent I spent quite a few years muddling about with these perplexing and difficult to understand electri cal systems and I was lucky enough not to burn up anyone s boat or to make too many other disastrous mistakes Then I discovered the ABYC and became Copyright 2000 2007 by Edwin R Sherman Click here for terms of use INTRODUCTION familiar with its comprehensive Standards and Tech nical Information Reports for Small Craft Suddenly my work as a marine electrician became much eas ier I now had uniform electrical standards to work with and to learn from Information on wire types insulation materials color codes and wire sizing was clearly laid out and understandable even to those of us with limited training and experience The hearsay gue
308. n the cell and the specific gravity moves closer to 1 000 A specific gravity reading that shows a 50 point difference between any two cells after re charge and stabilization indicates that your battery needs replacement Figure 5 16 shows a hydrometer in use Experi ment a little if you re going to use this method of checking your batteries Always wear safety goggles when working around batteries Hold the hydrometer in an upright posi tion and draw in just enough electrolyte to float the bulb no more or less Too much electrolyte in the hydrometer tops out the bulb and gives you a false high reading When not enough electrolyte is drawn into the hydrometer the bulb float indicates a bad cell that s really good Carefully squeeze the elec trolyte back into each cell as you check and record each cell s reading When you have taken a reading from each cell wipe away any electrolyte drips from the battery top and throw out the rag Open Circuit Voltage Test The newer sealed batteries cannot be checked with a hydrometer but you can still test the specific gravity on these batteries You can t compare individual cells within a sealed battery because you don t have a way to get into them However this test is still a good way to evaluate the overall state of charge of a sealed bat tery If you have a digital voltmeter built into your boat s instrumentation you can continually moni tor the state of charge This test
309. n Shore Power Black White Green Branch Circuit Breaker Typical T Disconnect Circuit Breaker 7 9 120 VAC Device JE 120 VAC Grounding Type Receptacle lt lt d 2 Pole 3 Wire Grounding e ional Ve Plugs amp Isolator eceptacles Grounding Conductor Green Underground Conductor Black Grounded Neutral Conductor White Shore Side Boat side Polarity Indicator To Engine Negative Terminal or its Bus Fig 11 1 Typical shore power wiring diagram through the AC distribution panel to an outlet ABYC considerations when wiring for AC Unlike DC however voltage drop through the circuit is really not much of a factor in AC circuits It s not that volt age isn t lost as it finds its way through an AC circuit but for the lengths of wire runs used on the small boats discussed here and because of the physical considerations cited above voltage drop is an insignificant factor so insignificant that the ABYC doesn t even take it into consideration in its electrical standards for AC circuits Wire sizing of AC circuits is easier as a result of this disregard for volt age drop with amperage requirements being the only consideration when designing circuits Wattage however is an additional element we must take into account here In chapter 1 you ll re call I discussed the Ohm s law equation and an addi tional
310. n electrolyte An electrolyte can be any electrically conductive material electrolytes are an important component in popular energy drinks like Gatorade and when any two metals are sus pended in it they will produce an electrical voltage between them Voltage you ll remember is the po tential to produce electrical current and thus is the only electrical value that s static The magnitude of the voltage will always be different for different com binations of metals and electrolytes The electrolyte used in your boat s batteries as well as in your car batteries is sulfuric acid and the dissimilar metals are lead dioxide in the positive plate or cathode and sponge lead a porous form of pure lead in the negative plate or anode Thus all such batteries are called lead acid batteries As a lead acid battery is discharged the acid elec trolyte is chemically converted to water this ex plains why batteries can freeze and why the specific gravity changes all of which we will cover later and the plate material is converted to lead sulfate To recharge a battery you pass through it a 12 volt charge that converts the three active materials back into their original state The actual chemical formula for this process when set in 10 point type is some 4 inches long which is why I decided not to go into it any deeper than we have just done Copyright 2000 2007 by Edwin R Sherman Click here for terms of use POWERBOATE
311. n found on a bracket at the top forward end of the engine It will have two large wires and two small wires attached to it Look at the size of the wire on the solenoid terminals If the large wires are the same size as your battery cables typically 4 AWG or larger the solenoid carries starter motor current However if the large wires are smaller than the battery cables around the 12 10 or 8 AWG range the solenoid does not carry full 125 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS starter motor current The small wires are usually 14 or 12 AWG in both cases If you have a medium to large boat over about 20 feet with an inboard engine that does not have a remote solenoid it will have one mounted on top of the starter motor In this case it will have only one large wire with one end connected to the solenoid and the other terminal connected directly to the battery or to the battery selector switch Solenoid Test Testing a solenoid is really rather simple once you know what the four wires do One of the large wires on the solenoid comes from the battery and the other goes to the starter motor One of the small wires comes from the ignition switch and the other if there is one connects to ground Some solenoids are designed to ground through the case and the bolt that attaches it to the engine acts as the ground Fig ure 8 3a shows a heavy duty solenoid figure 8 3b shows a similar solenoid that does not carry full
312. n ideal conditions found on your boat which way the cost is measured The question is if I buy the new gel cell or AGM batteries what am I get ting for my extra battery dollars Are the AGM and gel cell batteries worth the extra money The answer is that there is no answer at least not one that fits all circumstances The type of battery that s best for you depends on your needs and the use to which you put your boat Here are some cost comparisons Comparing charging cycles to typical cost per bat tery gives you a feel for the true cost of these batter ies over the long haul Using a group 27 battery a common size for comparison gives a cost per cycle based on the average number of cycles in each type used above The table below compares typical group 27 deep cycle battery prices taken from the 2006 West Marine catalog and the average true cost per cycle Using a cost per amp hour calculation we can use the advertised total amp hour capacities for the three group 27 deep cycle batteries West Marine lists in the same 2006 catalog to arrive at cost over life of the battery see table on the next page Deep Cycle Batteries Cost Per Cycle Wet cell peas nem ere et 100 3 8 per cycle Gel cells eee see ee eR a 213 15 per cycle AGM Getaebere oO I HP E 200 7 per cycle Deep Cycle Batteries Cost ver Life of the Battery Battery Type Cost Formula Wetcell 90 amp hours 2 50 perc
313. n t as permanent as heat shrink and it s liable to wash off if exposed to fuel solvents or lubricants such as WD 40 You can do the same thing using colored wire ties which are a little bit messier but tend to be more permanent There are many other methods for wire identifi cation that are acceptable and are often used by both boat builders and owners The ABYC standard only states that some means of identifying the wires in each circuit should be employed All of the above methods are quite acceptable and are good alterna tives for any work you may do such as adding on new equipment Whatever means of circuit identification you select numbered or named labels colored heat shrink tubing or tape or a new one that you think up for yourself of this you can be sure knowing what every wire on our boat does where it goes and where it comes from is going to make your boating life much simpler when problems crop up Substituting Wire Colors Before we leave this fascinating discussion of com ponent identification we need to cover one other situation that might arise while you re working on your new ABYC compliant wiring system What if you need to replace the 14 gauge brown wire that connects your generator to the alternator and the only colors you have in your tool box are orange and yellow This brown wire is only 3 feet long and the electrical supply house which might or might not have it in stock is 45 minutes away Wha
314. n the circuit indicates a bad connection or possibly wire cabling that s too small Starter solenoid Starter motor grounded to engine Starter solenoid With the key off use your multimeter set up to read resistance and check for continuity a reading of very close to zero ohms between the terminal at connection B and ground on the engine block If you don t find continuity repair the connections or re place the wire Next turn the key to start and check for 12 volts at the terminal labeled connection A If 12 volts is not present the problem is somewhere in the wire from your starter motor switch or neutral safety switch Follow the steps described later to correct this problem If all seems well here proceed with the voltage drop test For each of the four steps to this test the engine must be cranking but not firing In step one con nect the meter as shown in figure 8 7a Your voltage reading with the engine cranking should not exceed 0 3 volt If it does then the connection at the posi tive battery post is bad the connection at the sole noid is bad or the battery cable is too small and must be upgraded to a larger one An easy way to check for a too small battery cable is to feel it as you crank the engine If it gets warm to the touch it s too small Step two of the voltage drop test as shown in fig ure 8 7b is to check the voltage drop through the solenoid Connect the meter d
315. nd shafts harnesses without a little slack to allow for flexing of the engine mounts can be pulled apart and the insulation on wires and 57 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS SINGLE BATTERY See E 11 12 1 2 Overcurrent protection device fuse or circuit breaker NL 72 m N Battery Cranking motor conductors no length restrictions A p Conductors to various m ded loads as neede Starter no length restriction Fig 4 17 Figure 15 from section E 11 on battery supply circuits showing the location of overcurrent protection ABYC DUAL BATTERY See E 11 12 1 2 Overcurrent protection device fuse or circuit breaker li 72 max Cranking motor conductors no length restrictions AL B Conductors to various loads as needed no length restriction NO BATTERY SWITCH See E 11 12 1 2 T 72 max E Battery Cranking motor conductors no length restrictions P 7 or 40 max Conductors to various loads as needed no length restriction Fig 4 19 Circuit protection in a dual battery installation ABYC cables near a hot exhaust manifold can melt away from the heat
316. nd the strength of the current The intensity of the magnetic field increases in direct proportion to the current flowing through the wire Thus the higher the current the stronger the magnetism Inductive pickup meters measure this magnetic force and convert the reading into amperes Meters with an inductive pickup can save a lot of time and they are much easier and safer to use than those that measure amperage with probes Just clamp the meter around the wire from which you want to take a reading and if you have the thing turned on and set properly the meter does the rest Also meters with an inductive pickup will have a small arrow em bossed on the inside of the clamp jaws This arrow should point to ward the power source in the circuit not foward the electrical load If you get it backward you ll get a negative reading Finally to ensure an accurate reading when using an inductive meter it s important to keep the jaws as close as possible to 90 degrees in relation to the conductor you re checking The inductive meters are a great choice for most of us but they do have their drawbacks An inductive meter can measure the amperage on only a single wire at a time so bundled wires or wires enclosed in insulation can be difficult to measure on occasion Also on circuits draw ing less than 1 amp of current some inductive meters may not be sensitive enough to get a reading In this case a less expensive con ventional meter may be
317. nderway Wiring harnesses that rub against moving pulleys hot exhaust mani folds and the like are electrical time bombs Check to be sure all wiring is properly secured and clearance from moving machinery is adequate Internal Shorts The third and final short circuit type we will discuss is the internal short a short circuit that can occur deep within the internal circuitry of the electrical appliance itself This type of short circuit is the most harmless of the three because it doesn t usually threaten the safety of our boats Internal shorts can however be expensive to correct because they often mean that expensive equipment will have to go into the repair shop or worse into the dumpster Often a short inside a piece of equipment will simply cause the equipment to stop functioning At other times the fuse or circuit breaker will trip without the risk of burned wires or insulation assuming the circuit protection is rated properly Tools Most of us will already have a good collection of ba sic tools However besides our regular collection of sockets spanner wrenches screwdrivers pliers and the like we ll need to acquire a few more specific items Once we start working with electricity and be gin performing serious electrical troubleshooting procedures and upgrades we are going to need spe cialized equipment that will allow us to work safely and do a proper job Figure 1 9 a photo of my personal collection of tools
318. ne electrician you should draw up your own wiring diagram for your boat if you don t already have one If you do have a wiring diagram it s very likely that you can make significant improvements with just a few revisions and additions and it s the purpose of this chapter to show you how to do this Follow the advice given here and you ll be well on your way toward understanding what wiring diagrams are telling you and you ll be able to properly upgrade your diagram as you add new equipment to your boat Copyright O 2000 2007 by Edwin R Sherman Click here for terms of use Wiring Diagrams A wiring diagram sometimes referred to as a schematic diagram is a wonderful tool often compared to a road map Suppose you were to find yourself in Salt Lake City for the first time and you were trying to get your new Ranger bassboat to Lake Mead to give her a spin The first thing you would be likely to do is reach for a road map Salt Lake City would be clearly shown on the map with graphic symbols that might tell you not only its location but its relative size elevation and in special cases things like its political and racial demo graphics Lake Mead would likewise be shown with graphics that would contain a lot of information about the lake such as its size shape pool elevation and any thing else the mapmaker thought was important The lines connecting the city to the lake would represent roads of course but you could also tell by th
319. need to join two wires of different gauges a sealer that s perfect for making waterproof connec tions anywhere on board Another new addition to the electrician s arsenal is the dual gauge butt connector These stepped con nectors provide a solution to the age old problem of connecting a smaller wire to a larger one Figure 4 33 shows one of these new connectors Chapter 5 Batteries and Battery Systems Of all the modern inventions that make life as we know it possible and more important make it pos sible for us to spend our weekends and holidays whizzing around various bodies of water in our powerboats the 12 volt battery has to be one of the most important Without that little plastic box full of acid and lead sitting in the bilge and the flow of electrons within it in a direct current path our boats and boating wouldn t even vaguely resemble the sport we love and enjoy All but the smallest dinghies and skiffs with hand crank motors rely on batteries for everything from starting the motors to keeping the beer cold Without that battery you and I would be rowing and as much as I admire healthful exer cise that idea lacks pragmatic appeal Oars worked just fine for great granddaddy but I enjoy flipping switches With a flip of the first switch the out drives lower into the water with a flip of an other switch the exhaust fans clear the bilge of fumes Flipping the next switch turns on the VHF for the lat est weather
320. ng Diagram 0 0 e eee eee eee 22 Chapter 3 Selecting and Using a Multimeter 25 Multimetefs eee e pier e eR neue a tents IRI RA un 25 Selecting a Multimeter 0 0 eee eee eee 25 Using Your Multimeter 0 cece 30 Measuring Amperage secet sae iaee ound RE REC ONDE ag areas 34 Measuring Resistance and Continuity 000 8 37 g Chapter 4 Wire and Circuit Protection Standards and Repair Procedures 40 Order Out of Chaos 0 ccc cece cece n 40 ABYC Standards and Recommendations ss 40 Basic Warlhg cseueeee v UOS bU eea a HUE goed 41 WIPE SIZE vues e de EYE E Aa ed E EEE E ERA 42 Wire Insulation 0 0 ccc cece eee e 43 Fuses and Circuit Breakers eee 46 Ignition Protection eeeeeeeeeee e 52 Testing Fuses and Circuit Breakers 00 0c cece eee ee 53 Levels of Circuit Protection ccc ccc cece eee eee eee 54 CONTENTS Acceptable Locations for Fuses and Circuit Breakers 55 Wire Routing and Support esses 57 Connecting the Dots Making Wiring and Connection Repairs 59 Chapter 5 Batteries and Battery Systems 65 How Batteries Work The Basics 0 e cece eee eae 65 Basic Chemistry 55 cone ieee acest epe eames Sia tase ned 65 Types of Lead Acid Batteries 2 0 0 0 cece eee eee eee 66 Which Battery Is Right for You
321. ng inside the combustion chambers and sends an electrical pulse to the knock control mod ule The module then sends a signal to the ignition module ordering it to retard the ignition timing in small 3 degree increments until the pinging stops In addition to controlling ignition timing to elim inate pinging the Thunderbolt V also controls engine over revving acceleration spark advance and idle speed It also has a feature called mean best timing although this feature is not available on all engines Mean Best Timing MerCruiser s Thunderbolt V system uses a sophisti cated feature called mean best timing MBT that fine tunes the ignition timing during light load cruising The ignition control module searches for the perfect setting for ignition timing by automati cally adding a few degrees of advance and waiting to see if the engine rpm increases If so the module will add a little more advance until engine speed stops increasing If the rpm drops for any reason such as a change in sea conditions the module will automat ically retard ignition timing as needed This is true electronic wizardry at its finest Idle Speed Spark Control The idle speed spark control automatically adjusts ignition timing so that a specific idle speed is main tained under different operating conditions This is accomplished by making small spark advance ad justments and is only used within a speed range that generally falls between 400 and 700 rpm
322. ng magnetic induction just like one on an inboard engine The voltage gener ated by the primary winding creates a magnetic field around the secondary winding which has many more windings than the primary coil The CDI unit controls the rapid turning on and off of electrical flow in the primary winding thereby turning this magnetic field on and off The effect of this is the same as described earlier The rapid movement of this magnetic field past the secondary windings in PRIMARY SECONDARY 12 Turns 120 Turns 12V 20A eme gt To circuit TUI Mi NODOOOGDOOOOOU Fig 7 10 Typical internal construction of an ignition coil showing the primary side windings with fewer coils and the secondary side with more windings 111 112 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS ws Fig 7 11a Surface gap and traditional spark plugs duces electrical current The more windings the more current is produced As the secondary voltage leaves the center tower of the ignition coil it travels through the spark plug wire the high tension lead which is heavily insu lated and designed to carry high voltage If all is well the high voltage will jump the gap between the center electrode of the spark plug and the ground electrode completing a circuit to ground On larger engines with surface gap plugs the side of the spark plug is the ground electrode Figure 7 11a shows both plug typ
323. ng system described in chapter 6 will help isolate the reason that your tachometer quit One caution here however On many diesel en gines a separate oil pressure sender on the engine switches the field voltage see chapter 6 This way even if the ignition key is left on the alternator will not get excitation voltage to the field windings until the engine is actually running and oil pressure closes the circuit These senders have a high failure rate and are often the cause of alternator failure on a diesel Check the engine manual to see if you have one of these switches If you do in order to check for field voltage at the F terminal on the back of the alternator either bypass the oil pressure switch with a jumper wire or do the voltage test with the engine actually running If no voltage is found then the switch on the en gine is not getting voltage from the ignition switch or the oil pressure switch is defective To check fol low the procedures outlined throughout this book for testing any switch If voltage is getting to the al ternator and all the other procedures from chapter 6 for testing the alternator have been followed a problem with the alternator or the internal voltage regulator is indicated Remove the alternator and send it out for overhaul Once you have determined that the alternator is not the cause for your tachometer failure verify the continuity of the wire connecting the tachometer to the back of the al
324. nge of the radio So when considering where to mount the an tenna on your boat try to get it as high as possible If you venture far offshore you may even want to con sider one of the antenna mast extensions available from Shakespeare and others as a means of getting your antenna as high as it will go The table in figure 12 4 shows the approximate range you can expect for a 25 watt VHF radio based on antenna height How Much Can Gain Antenna gain is another important consideration when trying to decide which VHF antenna to pur chase Gain describes the power amplification avail able through your antenna which refocuses the impedance of the antenna so that instead of trans mitting a large portion of the signal up into the sky and down into the water more of the signal is di rected out toward the horizon where it s much more likely to do some good Gain is measured in decibels dBs a logarithmic measure of sound and noise plus a few other things that don t concern us here Even though the Federal Communications Com mission FCC regulates the output of VHF marine radios to a maximum of 25 watts the effective radi ated power of the radio can be greatly increased by installing an antenna with a higher gain The gain of an antenna is fixed and can t be adjusted As an antenna s dB rating increases its radiated beam gets narrower or flatter so that an antenna with a very Transmitting Antenna Receiving Antenna
325. nical switch used to connect single or multiple batteries in parallel to a load battery isolator An electronic device that uses heavy duty diodes to block electrical flow in one direction effectively keeping batteries that are combined separated from each other electrically to prevent the discharge of one into the other battery reserve capacity The number of minutes a new fully charged battery at 80 F 26 7 C can be discharged at 25 amperes and maintain a volt age of 1 75 volts or more per cell 10 5 volts for a 12 volt battery blade type ATO fuse Common fuse type using a colored plastic case for the fuse element widely used in automotive applications today branch circuit mary circuit A subcircuit fed from a main or pri bus bar Metal bar used as a termination point for multiple conductors and circuits A common point for either grounding or positive power feed bus AGC fuse The traditional glass cylinder style of fuse cable Wiring of any type also cabling capacitive discharge ignition CDI unit The brain of a CD ignition system capacitor An electronic component that stores an electrical charge when voltage is applied Copyright 2000 2007 by Edwin R Sherman Click here for terms of use 193 194 GLOSSARY carbon tracking The carbon path etched into plas tic or other insulating material by high voltage cathode The negatively charged electrode of a cell See also anode cell
326. ns for 123 starter motor solenoids 125 28 126 127 134 35 starting battery 69 state of charge 84 static charge 83 stator windings 86 stop switch testing 115 119 20 121 stray current corrosion 177 78 sulfated batteries 66 67 surface charge 85 switches automatic float 142 battery 19 20 77 79 81 closed 2 engine ignition 133 35 134 neutral safety 128 129 130 132 33 stop 115 119 20 121 switch panels bilge pump 142 checking source voltage 34 master distribution 14 15 19 20 142 symbols wiring diagram 13 14 T tachometers 149 150 52 tape and wire ties 18 59 60 temperature compensation 98 temperature gauges problems 148 49 troubleshooting 152 53 wiring diagram 153 temperature ratings of wire 46 47 48 161 162 163 temperature sending unit 153 terminals color codes for 61 integrity 75 soldering 59 64 testing tests See also trouble shooting AC amperage 169 AC circuits 167 70 AC resistive equipment 170 alternator 91 94 amperage 42 43 93 batteries 74 76 82 85 battery chargers 89 94 99 battery charging systems 91 94 battery isolators 80 81 CDI units 118 charge coils 115 116 18 117 charging amperage 93 circuit breakers 53 54 compass deviation 181 continuity resistance 39 132 33 150 51 169 70 current draw 127 28 diodes 27 draw 94 fuel tank sender 154 fuses 53 114 galvanic isolators 179 GFCI outlets 16
327. nse the magnetism induced by current flow Let s look at them one at a time Bimetallic Circuit Breakers Bimetallic circuit breakers use two dissimilar metals such as copper and stainless steel fused together into a thin strip In a normal state this metal strip con nects the circuit inside the breaker As current flows through the breaker heat is generated and since the two metals have different rates of thermal expansion one metal expands more than the other bending the strip When the bending reaches a preselected critical point the contacts inside the breaker separate and open the circuit Magnetic Circuit Breakers We already know from our reading in chapter 3 that any conductor with current flowing through it will be surrounded by a magnetic field Our second type of circuit breaker senses this magnetism and when the magnetism reaches a critical magnitude the cir cuit breaker trips and opens the circuit Either of these two types of circuit breaker works just fine in most marine circuit breaker panels and it s perfectly OK to mix them In fact since they both function in exactly the same manner with no signifi cant external differences it isn t important that you know which type you have Just be certain that what ever breaker you select is designed for marine use and you ll be all set Removing Circuit Breakers A big problem with many of the circuit breakers I ve seen lately is in their labeling Circuit break
328. nstallation Happily the basic rules for handling alternating current on your boat are clear and these systems rarely cause a problem if these simple rules are followed Nearly all accidents involving AC on boats are caused by ignorance laziness blatant stupidity or some combination of all three of these things Most often a boatowner attempts to cut corners to save a little time or a few dollars on an installation and gets hurt or damages the boat in the process On one boat I recall the owner thought the best approach to 157 158 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS AC upgrades was to hire a licensed electrician to in stall the AC service The problem was that this par ticular electrician although probably a competent worker on shore based systems had no experience with marine electrical installations Within months after a major refit to the boat a fire broke out on board and the boat burned to the waterline The in surance investigation revealed that the fire was caused by the boat s new AC shore power system This was a lesson hard learned for the owner and for the electrician If you re having an AC system professionally in stalled on your boat ask your electrician if he or she has been certified by the ABYC to work on boats If not you might want to wait until they get certified or simply look around for an electrician who has passed the ABYC certification program Quality marine electricians are proud
329. nstallation If you re thinking of adding an inverter to your boat the best bet is to try and find an ABYC certified marine electrician The certified tech will be quite familiar with all the nuances of inverter instal lation and the end result will be well worth the la bor expense here Having said that the list of general guidelines that follows will enable you to at least converse with a professional electrician intelligently to come up with an installation solution that satisfies your needs Presently no one makes an ignition protected in verter The nature of the beast is that internal switching must be accomplished during operation and this switching process can create some arcing as the unit is working For this reason extreme care must be taken when selecting a location to mount the unit If your boat is gasoline fueled the inverter must be located in a compartment outside the en Alternating Current and AC Equipment Formula for Determining Battery Bank Size taking inverter inefficiency into consideration To find the amp hours drawn from the batteries by any given AC appliance powered by the inverter you must find the AC amperage or wattage consumed and apply one of the equa tions shown here DC Amp Hours AC amps x 10 x 1 1 x hours of use DC Amp Hours AC watts 12 x 1 1 x hours of use Fig 11 18 Battery bank size determination Typical AC Appliance Wattage Requirements Appliance
330. nstalled on the cord Marinco an electric supply company makes quality replacement plugs and sockets that are available at all good marine supply houses 189 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS may also be a consideration En try into the silent world of in verter power is considerably less expensive than purchasing a gen erator Noise and the exhaust fumes created by a generator are simply undesirable if a better al ternative exists Further many of the inverters available actually work in two directions creating the AC you want and also acting as high end multistage battery chargers for use at the dock when yow re plugged into shore power 170 Fig 11 14 The wiggle test on a shore power cord AC Resistive Equipment Checks To determine if the heater element in a hot water heater or any other appliance using a heating ele ment is OK you can also perform a continuity test First make certain that the breaker for the heater is off and verify that power is not present by using the inductive tester described earlier and shown in fig ure 11 10 on page 167 Next attach your meter to the black and white leads respectively at the terminal junction on the heater and check the resistance read ing through the heating element A resistance reading is to be expected if all is well If you get a reading of infinity or OL on your me ter the element has developed an open circuit inside
331. nstruction has reached new highs also Posts and case tops seem to remain sealed much longer than before so electrolyte leakage and the re sultant corrosion are not as important as they were I m still going to insist that you regularly check elec trolyte levels and terminal integrity though A faulty charging system can literally boil the electrolyte out of the cells damaging the battery and creating dan gerous hydrogen gas and it can do this in a very short period of time As you ll remember from the basics covered ear lier in this book loose or corroded connections cause excessive resistance and that causes heat When a high current is drawn from a battery such as when you start your engine a loose corroded connection can generate enough heat to actually melt the plastic casing of the battery around the ter minal stud This opens the door for an electrolyte leak at the terminal that further compounds your problems The following maintenance checklist will go a long way toward keeping battery problems at bay and I recommend doing at least the visual part of these checks once every week especially if you re hooked up to a shore power charger gt Keep the tops of your batteries clean and dry Use a little warm water on a rag to wipe away any ac Batteries and Battery Systems cumulated dirt and grime A mixture of baking soda and warm water is excellent for cleaning dirty or corroded batteries Don t overdo the b
332. nsure that you won t damage your meter or end up having a shocking experience Besides your multimeter several small inexpen sive testers can be extremely useful when working around AC systems Figure 11 9 shows an LED outlet tester with a built in GFCI test function and figure 11 10 shows an inductive voltage sensor used for verifying the presence of AC voltage even behind panels and through insulation The LED outlet tester is useful in determining whether reverse polarity ex ists and whether or not there is an open circuit in any of the three conductors It is not at all uncommon for low voltage to be a problem in an AC circuit or reverse polarity for that matter A disconnected green grounding conductor is quite common and can go unnoticed until some one gets a shocking jolt The good news here is that Alternating Current and AC Equipment these problems usually originate at the dock not on the boat and it s easy to check for them yourself Figure 11 10 demonstrates using the inductive AC tester to see if there is voltage present at an outlet If the tester s LED flashes and it emits a steady beep ing noise AC is present in the circuit The only remaining question is how much voltage To deter mine that you ll need your multimeter Fig 11 10 Using the inductive AC tester to check voltage at an outlet 187 188 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Checking AC Voltage When
333. nted out shortly the readings you get from your instruments could be slightly dif ferent than what s really going on in your engine The quality of instruments used on boats varies widely among boatbuilders In fact discrepancies between readings on different gauges and the actual readings at the engine are quite common What you as a boatowner should be looking for as you moni tor your engine s vital signs is any change from the established norm for your particular engine Any change in the reading of a gauge is a surefire indica tion that something is up and it could be a problem As already mentioned another common situa tion on boats with dual helms or dual engines or both is a variation in instrument readings between Copyright 2000 2007 by Edwin R Sherman Click here for terms of use 148 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS stations or between engines Often one gauge set will read differently from another not by much but dif ferent nonetheless The obvious question is is this a problem The answer is no I have wasted hours try ing to match gauge readings on boats with duplicate instruments Unless I was very lucky or was working on exceptionally high quality instruments my re sults were less than satisfactory The best gauges have calibration screws that enable you to fine tune the actual readings but don t count on finding these ex pensive gauges on a typical production powerboat Some manufacturer
334. o contacts If you do then ig nition output is satisfactory If not further investi gation will be needed If your engine is skipping or misfiring check all of the spark plug wires this way to be sure that each sec ondary coil is sending a spark through its respective plug wire to the spark plug The beauty of this spark tester over similar tools is that the air gap between the two contacts is adjustable This is important because some manufacturers will give an air gap specifica tion in their manuals The wider the air gap a spark will jump the higher the total ignition system out put So by comparing the maximum gap that a spark will jump for each ignition coil you can find a weak or faulty coil Be careful not to get the spark plug wires mixed up when you do this test Each wire is timed to a spe cific cylinder and must be replaced on the same spark plug from which you removed it If you don t see a spark check the fuse for the ignition system and re place it if it is blown Also if you have one make sure Ls Fig 7 13 Spark tester in use the emergency stop button and clip are set correctly It s amazing how easy it is to forget this simple de vice Check for spark again if it s still not evident further investigation will be needed Checking the Spark Plugs Just because you re getting adequate spark to the spark plugs doesn t mean the spark plugs are firing They could simply be worn out but there are m
335. o through a period of denial about their personal AC consumption whenever the topic of inverters or generators comes up Daily power consumption is the key to sizing not only the inverter itself but also the battery bank that s going to feed it Use of an inverter on board ties into much ofthe discussion throughout this book Battery types amp hour ratings reserve capacity wattage all of these factors must be given serious consideration if you hope to be successful with an inverter selection and installation AC Need Analysis The first step in inverter consideration is to perform an honest and accurate analysis of your daily AC us age If all you want is to occasionally recharge a lap top computer or rechargeable electric drill battery your needs are minimal You ll be served well by one of the small portable inverters on the market today But if you intend to run a TV microwave oven and possibly a refrigeration system in addition to sup plying outlets for use with things like hair dryers and coffee makers you re going to need an inverter that packs some real punch What this all boils down to is wattage and how many hours per day you ll be us ing these appliances Be sure to consider usage many of the appliances you ll be running from the inverter will be used in termittently If you re going to be running a mi crowave simultaneously with a coffee maker your total wattage needs could easily be as much as about 2 500 watts
336. oard com munication system Although cell phones have become popular in re cent years the best way to get help when the chips are down is still via VHF radio transmission For this reason the VHF radio needs to be installed safely You may need it when things aren t going so well on Fig 12 2 A typical factory harness with in line fuse holder installed your boat DC Panel s Sepang Positive Bus DC To Electronic Equipment e E DC From Negative Bus amm Electronic Equipment Fig 12 3 Dedicated bus bars to supply electronic equipment branched off the main distribution panel 183 184 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Remember that transmission power with a VHF radio is proportional to the power supplying the ra dio While transmitting VHF power needs are ap proximately four times greater than when the radio is receiving You may need to use the radio when max imum battery power isn t available the very reason for your call for help could be that your batteries have drained enough so you can t get your engine started Poor quality connections and undersized wires supplying the VHF could induce excess volt age drop to the transmitter so be sure this end of the installation is absolutely first class Your next concern is the line of sight nature of VHF radio signals The higher your radio antenna is mounted the greater will be the effective ra
337. of 0 36 volt which means that 11 64 volts would be the minimum allowed at the appliance Measuring Voltage Drop Method 1 So now that you have an under standing ofthe voltage drop that s al lowed in critical and noncritical circuits how can you actually mea sure it with your multimeter There are two methods The first method is probably the simplest to understand but it won t always give the best re sults when you re trying to isolate the 32 Fig 3 5 Cabin light circuit diagram with a voltmeter connected to check volt age going to one of the light fixtures exact spot in the circuit that s causing a problem Selecting and Using a Multimeter Circuit Protector Cabin Light Cabin Light Battery Cabin Light circuit is on and the bulb is lit If you re working with one of the more modern bay onet bulb holders connect the red probe to the left side bulb clamp and the black probe to the right side and take a direct reading If the reading you get is the same as the reading at the battery or distribution panel great No voltage drop is present If the reading is lower than the source voltage as it usually is there is a voltage drop pre sent To measure it subtract your reading from the source voltage The difference be 7 tween the two readings is the voltage drop ne between the power source and the appliance Record the reading To determine the c percentage of drop subtrac
338. of these cir cuit breakers might be associated with your charging system and might have to be reset Just remember that when a circuit breaker of any type is tripped there is always a reason for it and further testing will determine the cause Check the entire system for cor roded battery terminals loose connections on the alternator and perhaps a corroded plug on the har ness that connects the engine wiring to the rest of the boat s systems Engine Ground Make certain that the alternator is well grounded to the engine The alternator is sometimes grounded with a short jumper lead from the alternator body to the engine It will be connected to a terminal marked Battery Charging Systems GND on the back of the alternator Other times the alternator is grounded by an internal connection so make sure all the mounting bolts are free from cor rosion and tight Also make sure that the engine s ground strap is secure The alternator is only grounded as well as the en gine to which it s bolted Clean and tighten the ground strap and mounting bolts as required but disconnect the battery first If you short out any of the terminals with your wrench you may create more damage Testing the Charging Cystem If after making all the preliminary checks listed above your problem still exists it s time for some in depth investigation Start at the heart of your charg ing system the battery If the battery has failed the be
339. off has been dealt with hook up your voltmeter across the battery you re testing just as you did with the open circuit voltage test With the meter set to the DC volts scale crank the engine over for no more than about 15 seconds Carefully observe the meter s lowest Batteries and Battery Systems reading in volts during the cranking If it drops below 9 6 volts perform a three minute charge test to determine if the battery is worth saving With elec tronically fuel injected engines the minimum crank ing voltage allowed is 10 5 volts Three Minute Charge Test Begin the three minute charge test by disconnecting the battery s ground cable to take the battery out of the boat s circuitry This will prevent any voltage spiking of precious electronic equipment you have on board Next connect your multimeter set to mea sure voltage across the battery terminals Connect a battery charger with a quick charge capability to the battery The charger should have 40 to 50 amps of output so it s not your typical trickle charger Turn the charger on to about 40 amps and maintain this charge rate for three minutes while you observe your voltmeter The battery is serviceable if the voltage reads less than 15 5 volts during the three minutes Recharge the battery and redo the load test to be sure everything is OK If the battery reaches more than 15 5 volts during this three minute period it s time to replace the battery After going through thi
340. ogy out of the way Basic AC Terminology gt Polarity Obviously with the anode and cathode continuously reversing positions our old concept of opposing plus and minus terminals or poles no longer works for AC Many electricians who should know better almost all of us in fact refer to the hot lead the black one in an AC circuit as the positive and the grounded lead the white 156 one as the negative In actuality each wire takes turns being positive then negative several thou sand times a minute If you choose to use this pos itive negative distinction to describe AC wires you must keep in mind the fact that there is no true polarity in an AC circuit as there is ina DC circuit Ironically because of the physics involved the proper wiring of AC circuits or polarity if you like is even more critical than it is in DC circuits as we will discover a little later on Frequency The frequency of an AC circuit is sim ply the rate at which the current reverses itself In most American countries the standard is 60 cy cles per second which means that the electrons hop back and forth 60 times every second Fre quency is measured in Hertz Hz so the standard in the United States is called 60 Hz service Eu rope and Asia use 50 Hz service On boats frequency is particularly important when dealing with generators as we will see Resistance Resistance as you ll recall is an im portant component of any DC cir
341. omponents When people think of their boat s electrical system and its parts they generally don t think ofthe engine ignition system as being a part of it Well if your engine suddenly quits one day and you find that the fuel system is OK then the most probable cause for the shutdown will be a faulty ignition system and you ll definitely be working with electrical compo nents to correct the problem If your boat has a diesel engine it neither has nor needs an ignition system and you can skip this chapter reveling in the luxury of never being trou bled by overgapped spark plugs out of control con trol modules or miswired ignition wires However if you own a small to medium sized powerboat the chances are very good that it s powered by a gasoline engine replete with a complex assortment of igni tion system parts All gasoline engines need an ignition system to light the sparks that fire the cylin ders that turn the crank that spins the prop that gets us over the water to where we want to go Inboard gasoline engine ignition systems all work on the same simple principles When you turn your starter switch the ignition control mod ule or CDI unit senses your desire to start the en gine Electrical energy is drawn from a battery usually and sent to a coil where it s transformed from a low voltage to a very high voltage From the coil this high voltage is sent via heavy ignition wires to the distributor where it s directed throu
342. on module where it is converted to direct current via a rectifier circuit built into the ignition module Once converted the current is stored in a capacitor an electrical device designed to temporarily store an electrical charge which is also built into the igni tion module for later delivery to the ignition coil feeding a given cylinder Unlike most inboard sys tems outboard engines use an individual coil for each cylinder The second coil also found under the engine s flywheel is known as the sensor trigger or pulsar coil depending upon the engine manufacturer we will use trigger coil This coil sends a much smaller volt age typically from 1 to 9 volts to the same ignition module as the charge coil where it triggers a transis tor a silicon controlled rectifier or SCR matched to a cylinder Once the SCR gets its cue it triggers the capacitor to release its stored charge and sends it to the primary side of the ignition coil for the cylinder that needs to be fired A much higher voltage is sent to the primary side in outboards and PWCs than is sent in the inboard engine systems The output of the secondary side of any ignition coil is proportional to the input on the primary side By sending a much higher voltage into the primary side ofthe coil we get the same high output from a physically smaller pack age than on inboard motors this saves valuable space under the outboard engine cowl These systems are generally referr
343. on Problem Quick Check List If you have checked the spark plugs as described above and determined that you don t have a spark at any of the cylinders or you have a spark at some cylinders and not at others further investigation is needed The following list will help organize your search through the ignition system and the accom panying tests will help you to pinpoint the source of a problem These tests should only be completed us ing this book and the manual for your particular en gine Each manufacturer uses different color coding for wires and slightly different test procedures for their respective systems However by following this guide you should be able to trace your way through your system and isolate any problems in the CDI unit in the rare instances when you have a problem These tests assume that you have eliminated any possibility of a problem with fuel or compression The sequence for testing your outboard or PWC ig nition system is as follows 1 Check to see if your engine has a fuse for the ignition system If it does check the fuse and replace it if it s blown or corroded Check the spark plug wires Test all the ignition coils Do a water spray test of the engine m d m oM Test the charge and trigger coils and output to the CDI unit using your multimeter and Mer cury DVA tester part number 91 89045 B Test all engine stop circuits 7 Test the tilt switch if your engine is equipped with one Let s
344. on these small engines generally produce between 4 and 6 amps of current at maximum output The problem is that even this small amount of current can be too much if the battery is charged and you aren t using any electrical equipment This constant charge creates a built in overcharge that will boil away bat tery electrolyte If you have one of these small motors it s critical for normal battery life that you check and top up the electrolyte frequently You should never use anything but a wet cell battery on these motors This nonregulated system consists of four major components plus the wiring that connects them all On the top of the engine there are permanent mag nets attached to the inside of the flywheel and a series of stator windings When the engine is running the permanent magnets spin very close to the stator windings and produce alternating current via mag netic inductance just as it s produced in the inboard alternator discussed above This alternating current is converted into direct current that can be used to charge the battery by passing it through a diode rec tifier that s slightly different than a bridge rectifier This rectifier is not contained in the same housing as the alternator as are the ones found on inboard alternators It s really nothing more than a group of diodes mounted in a heat sink that s bolted to the engine block The heat sink provides a ground and helps conduct the heat away from the diodes Some make
345. onal offerings And when buying a boat ensure that itis NMMA certified using ABYC standards Over the years I have come to know Ed as both a professional and as a friend As a professional he has designed both the ABYC Basic Electricity course and the ABYC Electrical Certification course He also has recently completed the National Marine curriculum guidelines for secondary schools that offer ABYC endorsed technical marine programs and he has codeveloped a post secondary Marine Systems Cur riculum that is scheduled to be implemented in a number of schools across the country Ed s teaching and writing skills and his rapport with students are legendary and beyond reproach He is regarded as an industry expert in the area of electricity and marine electrical systems and as such is an active member of the ABYC s Electrical Committee And yes Ed holds an ABYC Electrical Certification The first edition of Powerboater s Guide to Elec trical Systems has been read and used as a reference document by tens of thousands of marine profes sionals technicians students and boating enthusi asts It is considered a must have reference guide because it is able to convey concepts and practical knowledge of complex material in a user friendly manner It speaks to both the technically minded as well as to the novice boatowner It also stresses the importance of adhering to industry standards in or der to do the job right the first time The sec
346. ond edition has new information takes a fresh look at industry technological advances and captures the essence of what you need to know re garding electricity and electrical systems used on boats yachts and marine craft It discusses the ba sics as well as advanced techniques concerning maintenance troubleshooting and repair of marine electrical systems More importantly it does all this in the context of the latest ABYC standards which have significantly evolved and changed since the publication of the first edition In closing as a friend and work associate Ed Sherman can be counted upon to give you candid and sage advice and expert counsel I look to him to help shape and guide the future of the ABYC and our education training and certification programs He sa team player who is looking out for the indus try and the boaters we serve and as such has his eye on the end goal safer boats for safe fun and mem orable boating experiences for all I encourage you to read digest understand and use the material in the second edition of Powerboater s Guide to Electri cal Systems you ll be glad you did Skip Burdon President and CEO American Boat amp Yacht Council Preface to the Second Edition Since the first edition of the Powerboater s Guide to Electrical Systems was published in 2000 there have been many evolutionary and some revolutionary changes to marine electrical systems and significant updates to the stand
347. onnections then check the engine and reverse gear assembly to be certain they are not bound up If these check out OK make sure the ca ble connections at the starter motor are tight and clean Finally if all the wiring and the engine itself seem to be in good order the starter motor itself is the likely culprit gt The starter motor turns intermittently Check the terminals at the ignition switch the ignition switch itself the neutral safety switch the engine mounted slave solenoid or relay and finally the starter motor itself gt The starter motor doesn t turn but the solenoid makes a clicking sound Check the battery and connections the solenoid the engine and drive for seizure and finally the starter motor itself Starter Motor Solenoid Relay Battery Fig 8 1 OMC Volvo Penta starter motor circuit gt The starter motor doesn t turn and the solenoid makes no clicking sound Make sure the remote shift lever is in neutral then check the battery and connections all fuses and circuit breakers and the starter motor solenoid gt The starter motor remains engaged and runs with the engine Check for a faulty or shorted ignition switch a faulty solenoid or a faulty starter motor This list should make it clear that the most com mon cause of all the starter problems except for a starter motor that remains engaged with the engine running is found in the battery and cable connec tions Th
348. onsiderably lower level This start up current must be accounted for but a more serious possibility is a locked rotor condition that occurs when the motor is getting power but the armature is prevented from turning This can be caused by corrosion in the motor hous ing or bearings or it can happen when a bilge pump motor gets a piece of debris jammed in the pickup or impeller of the pump When this happens the flow of electrons increases dramatically The ABYC standards provide that the circuit pro tection preclude a fire hazard if the motor circuit is energized for seven hours under any conditions of overload including locked rotor The best way to make sure you re complying with this rule is to care fully follow the installation recommendations pro vided by the manufacturer If you don t have the printed recommendations for the motor call the company and ask for them The only alternative is to test amperage drawn by the motor while it s in a locked rotor condition and this is not a very practi cal solution for the average boater Nonmotor Circuits The ABYC standards address circuit protection for nonmotor loads more clearly than they do protection for motor circuits Basically the rating of the fuse or circuit breaker used on a nonmotor circuit must not exceed 150 percent of the maximum amperage of the smallest conductor feeding the appliance Odds are good that when you determine the current of an ap pliance you ll discover
349. ooting 189 90 float final phase 98 Fluke RMS multimeters 11 30 flywheel 104 116 118 121 four step chargers 96 frequency 156 fuel gauges problems 149 152 troubleshooting 153 54 wiring diagram 153 fuel tank sending unit 153 54 fuses 2 47 48 AGC 48 49 ATO 48 49 50 circuit breakers and 50 51 corrosion 142 locations for 55 57 MDL 48 49 141 174 100 150 percent rule 54 55 56 ratings 48 7 40 72 rule 57 58 sizing 137 38 INDEX standards for 46 51 testing 53 114 gain antenna 184 185 galvanic corrosion 177 galvanic isolators 177 79 galvanic potential 66 gasoline engines See ignition entries outboard entries starter motor entries gasoline engines CCA ratings for 71 72 gassing 67 gauges abnormal readings 149 console mounted voltmeters 149 152 153 fuel 149 152 153 54 future equipment and 155 mechanical 147 oil pressure 148 152 153 154 155 temperature 148 49 152 53 trim 149 154 gel cell batteries 67 68 69 97 General Motors V8 engine 154 155 generators AC 172 175 77 176 GPS global positioning system receivers 181 190 91 grid of battery 66 ground 1 engine 91 shorts to 9 10 ground continuity 127 grounded conductors 158 159 grounded lead 156 159 ground fault circuit interruptors GFCIs 158 166 67 grounding lead 159 187 grounding lug 187 Guest 78 178 harnesses See wiring harnesses Heart Interface Link 1000 174 1
350. op manual you can check your charge and trigger coils Permanent magnets rarely lose their magnetism and don t need to be checked So what s next Your engine stop circuits and a few thoughts on some of the other functions your CDI unit may have Testing Your Stop Switch Your engine depending its size and the way it s in stalled might have a remote key switch to turn the ignition on and off or it might have a simple stop button mounted on the engine or steering tiller In ei ther case the tool of choice for testing the stop switch circuit is your multimeter set to read resistance You also need the wiring diagram for your engine If you don t have a remote control starter switch look under the engine cowl where the wiring and ca ble controls come out of the steering tiller You should find two wires one going to ground and the other going to the CDI unit Verify you have the cor rect wires by checking your engine wiring diagram Next find a good ground on your engine Install the emergency stop clip if your engine has one and make sure your engine is ready to run Connect your multimeter s black probe to ground and the red probe to the plug or to the wire coming from the stop button If all is well you ll get a high infinity reading indicating an open circuit Any reading showing continuity indicates a defec tive switch or a short to ground in the wire coming from the switch somewhere inside the tiller handle In either cas
351. ople who captured the concept of electricity and made it useful to people like you and me who own boats There is a fifth term also named after an early experimenter that s gaining favor with the knowledgeable and trendy among us the joule The unit of electrical resistance the ohm was named for Georg Ohm the German scientist who gave us Ohm s law The electrical symbol used to ex press the value for ohms is the Greek letter omega shown in figure 1 6 on page 6 When used in Ohm s law however resistance is represented by a capital R Alessandro Volta 1745 1827 was an Italian physicist who gave us the unit of electrical force called the volt The electrical symbol for volts is so simple that it doesn t need an illustration it s just a capital V However when used in the formula for Ohm s law voltage is represented by a capital P which stands for potential Switch On POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Andre Marie Ampere 1775 1836 was a French physicist whose namesake is the electrical unit that de scribes the rate of electrical flow through a circuit that we call the amp The elec trical symbol for amps is a capital A When working with Ohm s law we use a capital I for amps James Watt 1736 1819 was a Scots mathe matician credited with sig nificant improvements of steam engines who coined the word horsepower to measure the amount of work a machine is doing Horsepower is fine for
352. or Battery B Ground Light Battery rotation must be considered If you have a twin engine Red Ignition Black Ground B 9 W Tachometer Late Motorola Prestolite Delco Style fits Style Fits Mercruiser amp OMC MerCruiser amp OMC AC Tap Tachometer Red B i B Battery Sense Terminal Not Used o utput D Indicator Light Not Used B Y Ground Sense Red B Battery Sense Output Terminal Late Mando Style Fits boat the engines may rotate in opposite directions to compensate for torque The alternators on twin engine boats may not be inter Late Motorola Prestolite Style Fits U S Marine AC TAP Tachometer Terminal a Ad B E Battery changeable without switch Output ing the pulleys and fans 1 amp Straight fan blades onan al iw ternator usually indicate that Us exo the unit will cool rotating in either direction If the blades MerCruiser and Others PAC TAP Tachometer Terminal B Battery Output L2 Indicator Light e EXC Purple or Black S Red Wire Wire Ignition Terminal Battery Sense Fig 6 1 Seven common alternator backs showing wiring connections the back of the alternator to ensure that the wires go back where they should Incorrectly reconnecting these wires will render the new alternator inoperative or burn it out In the seven diagrams on page 88 in figure 6 1 alternators used by MerCruis
353. or a rare occurrence or by a fault in one or more of the alternator s recti fier diodes Unless your boat is equipped with an am meter and most are not you ll need to test the charging amperage with your multimeter The in ductive multimeter such as the one I discussed in chapter 3 is the easiest to use for this test Clamp the inductive pickup of the meter over the largest wire coming from the back of your alternator the one on the terminal marked B and take an Fig 6 8 Using an inductive ammeter to check alternator output When checking amperage output in this fashion turn on all your DC accessories and see if the alternator can keep up to the demand Battery Charging Systems amperage reading with the engine running at about 50 percent of normal rpm and with all your DC ac cessories turned on As the alternator tries to keep up with this load the ammeter should read very nearly the full output If it doesn t read full alterna tor output don t be alarmed as the reading will vary depending upon the number and extent of the loads you turned on If you re checking this system be cause your battery has gone dead and the reading you get is much below about 35 to 40 percent of the alternator s rated output there may be a problem and further testing is called for Figure 6 8 shows the amperage test Two additional tests the ripple voltage test and the draw test are needed to confirm if an alternator problem ex
354. ors are rated to carry a maximum amount of amperage so you need to se lect the correct unit for your boat s system Standard BATTERY EE vox D 2 m re A RPS 12 S N 36000523 C n9 iar Fig 5 9 Typical battery isolator Alternator Isolator Switch Starter Motor Solenoid Parallel Batteries Fig 5 10 Typical two battery installation with isolator in stalled 79 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS ratings are 70 130 and 160 amps The rating you use should be at a minimum equal to your engine alternator s maximum output capacity Check the manual for your boat s engine to get this specification Isolators are also configured to be used with either two or three battery systems so make sure you have the correct one for your system before you install it Figure 5 10 shows a typical two battery system with an isolator installed The current flowing through the circuit shows the isolator effectively separating the two batteries so that one cannot discharge into the other Isolators have several faults that you need to be aware of before you buy one First the diodes used in them are electrically expensive The big diodes have an inherent voltage drop of around 0 7 volt or almost 6 percent of the system voltage this means that charg ing times will be just that much longer The second problem with isolators is heat All diodes produce heat it s where that 0 7 vo
355. ost neglected Most medium sized and larger boats will use a variety of sizes of cables in the battery system A medium cruiser for example might have AWG 00 cables the diameter of your thumb between the individual bat teries and AWG 2 cables connecting the batteries to the boat s systems In general conductors larger than AWG 8 are called cables instead of wires and the wire end fittings are called lugs instead of terminals Battery cables as with any other wiring on board your boat must be large enough to carry the current that the equipment connected to them will need The size of battery cables is based on the maximum am perage that the starter motor and other high demand equipment needs Manufacturers generally do a good job of providing information on cable sizes in their workshop manuals The table below shows minimum AWG cable sizes required for various installations When using this chart to select cable sizes the positive and nega tive cables must be the same size Typically the gauge of the wire will be embossed on the insulation for easy identification Battery Selector Switches We have already established the need of larger boats those much bigger than an open runabout for a Battery Cable Recommendations AWG Gauge and Cable Length Metric Equivalent Upto 3 feet 1 1m ears 4 25 mm 3 6 feet 1 1 1 8 m 008 2 35 mm 6 I feet 1 8 2 3 m 1 50 mm 7 9 feet 2 3
356. other fine meters of course but Fluke s top of the line Model 336 offers one additional feature that will be useful if your boat is equipped with extensive AC circuitry such as a generator inverter or air conditioning and refrigeration systems This meter will measure up to 600 amps DC and 600 amps AC far beyond what most boaters need It does not have a diode test function however nor will it measure AC frequency Figure 3 3 shows a Fluke Model 336 true RMS clamp type inductive meter It s available through all the major marine supply houses in the United States for about 275 Fig 3 3 Fluke Model 336 clamp type meter This is a true RMS root mean square meter that can read up to 600 AC or DC amps This is an excellent choice if you do a lot of AC work Its shortcoming is that its ohms scale is not as sensitive as other meters I ve used This model sells for about 275 Both of these meters come with fairly easy to read instructions but be warned that the meter com panies in general assume that you know how to attach the meters to the circuit correctly for the mea surement you re making Reading the sections that follow will assure that you do Using Your Multimeter There are literally hundreds of checks and tests that you ll be able to carry out with your new multime ter However at least 90 percent of everything you ll ever need to do will involve some form of the fol lowing four basic procedures voltage measure
357. ould receive from electri cal appliances on board if they are not properly con nected or if a fault occurs anywhere in the system This coupled with the fact that appliances will work just fine whether this wire is attached or not is why ensuring continuity throughout the circuit all the way to the shore power box is crucial ISO Color Coding If your boat is not built to U S specifications there may be some variations in the color coding scheme described above The International Standards Orga nization ISO whose standards are used in many countries prescribes the following colors for use with AC installations gt For hot conductors ungrounded either black or brown wires must be used gt For neutral grounded conductors either white or light blue wires must be used Alternating Current and AC Equipment gt For ground grounding conductors either green as with the U S system or green with a yellow stripe may be used If your boat is wired using the ISO system and you re making additions or modifications it s an ex cellent idea to stick with the existing color code rather than changing or mixing the codes However in the United States you might have trouble finding wire in ISO colors in which case you should improvise your own coding system as described in chapter 2 Reverse Polarity Reversal of the black and white leads on an AC cir cuit creates reverse polarity where the white wire becomes the ho
358. our batteries The voltage regulator also controls the output of the alternator so that it doesn t overcharge your batteries Alternators work on the principle of induction discussed in the Word about Inductive Pickups sidebar in chapter 3 whereby a magnet placed adja cent to a wire will induce electrical current in the wire Each stator winding in your alternator has a very long wire wound in a coil and the rotor is a powerful electromagnet By spinning the rotor inside the stator electrical current is induced in the stator and by varying the amount of magnetism in the rotor the primary function of the voltage regulator the amount of electrical current produced by the stator can be precisely controlled Remember all conduc tors with electrical current flowing through them are surrounded by a magnetic field We can induce elec tron flow in nearby conductors by rapid movement of this field in proximity to the conductors this works in reverse as well by moving a conductor rapidly in close proximity to a stationary magnet If the stator windings in your alternator there are usually three all had the same polarity the positive and negative terminals arranged the same way you wouldn t have an alternator you would have a gen erator producing direct current However alternators have their stator windings arranged in fingers so that as the rotor rotates past the stator windings the posi tive and negative poles are constantly and
359. our dealer If you can get at the wiring on the back side of your shore power inlet trace the green wire through to the AC master panel If the boat has an isolator it will be mounted here Figure 11 23 shows a ProMariner gal vanic isolator which uses a capacitor installed on the green wire Testing Galvanic Isolators A simple test to make sure your galvanic isolator is working as it should once you re certain you have one is to use the LED tester shown in figure 11 9 on page 167 to determine if Alternating Current and AC Equipment your boat doesn t have a galvanic isolator installed and you spend a lot of time at the dock it would be a good upgrade to any AC electrical system You can do this one yourself rather easily Just make sure that the isolator you select is rated for the proper amper age at least the same as your boat s AC rating or more and preferably with a built in capacitor for added protection to the unit itself Also remember to mount these units in a spot that s relatively easy to get at and will offer good ventilation Remember that this chapter is not intended to make you an expert high voltage electrician It s in tended to give you a little confidence for basic sys tem checks and to enable you to talk with a marine electrician as an informed consumer If you still get nervous around shore power stay away from it Call in the experts an open circuit exists in the grounding conduc tor If
360. ouse battery Used to supply DC loads other than the engine stater motor hydrometer A float type device used to measure the specific gravity of a fluid relative to another In electrical work the battery hydrometer is used to measure the specific gravity of the battery elec trolyte relative to pure water ignition protected A critical designation for any electrical device that is to be used in an area where gasoline battery or CNG or LPG vapors may ac cumulate The ABYC describes ignition protec tion as the design and construction of a device such that under design operating conditions it will not ignite a flammable hydrocarbon mixture surrounding the device when an ignition source causes an internal explosion or it is capable of re leasing sufficient electrical or thermal energy to ignite a hydrocarbon mixture or the source of the ignition is hermetically sealed It is impor tant to note that unlike most of the ABYC stan dards ignition protection requirements are also mandated by USCG regulations and compliance is not voluntary but mandatory impedance A form of resistance the ratio of volt age to current inductance See cross induction induction See cross induction inductive pickup Used with measuring instru ments to sense electrical current flow through wires in line fuses etc A series connection insulator Material with a high electrical resistance intercircuit short Anywhere two circuits inadv
361. owers Fuse or switch to blowers Dark gray Gy Navigation lights Tachometer Fuse or switch to lights Tachometer sender to gauge Brown Br Generator armature Alternator charge light Pumps Generator armature to regulator Generator Terminal alternator Auxiliary terminal to light to regulator Fuse or switch to pumps Orange O Accessory feed Ammeter to alternator or generator output and accessory fuses or switches Distribution panel to accessory switch Purple Pu Ignition Instrument feed Ignition switch to coil and electrical instruments Distribution panel to electric instruments Dark blue Cabin and instrument lights Fuse or switch to lights Light blue Lt Bl Oil pressure Oil pressure sender to gauge Tan Water temperature Water temperature sender to gauge Pink Pk Fuel gauge Fuel gauge sender to gauge Green stripe G x Except G Y Tilt down and or trim in Tilt and or trim circuits Blue stripe Bl x Fig 2 5 ABYC recommended color codes from their E 11 standard Courtesy ABYC Tilt up and or trim out Tilt and or trim circuits NOTE 1f yellow is used for DC negative blower must be brown with yellow stripe Figure 2 5 at left lists the ABYC s recommended color codes and the circuits or parts of circuits they serve as found in Standards and Technical Informa tion Reports Standard E 11 tables
362. ows a typical diagram for a tachom eter circuit on a gasoline engine In addition to the From Ignition12V Instrument Common Ground To Pick Up Point of Ignition Fig 10 1 Wiring diagram of a typical tachometer circuit gray sender wire wires provide battery power to the instrument and a return to ground Figure 10 2 shows the battery power to the tachometer be ing checked with the ignition key on Where the ABYC color coding is used this wire will be purple Note that a small jumper is built into the gauge to connect power to the instrument light If no power is available at this wire when the igni tion key is on make sure that the lanyard safety key is installed if the boat has one all newer boats have one If it is using the methods previously described check all the connections and the condition of the lanyard switch Continuity tests and voltage tests may be used here Next verify the continuity of the ground with your multimeter Check between the GND black wire terminal on the back of the tachometer and a good ground on the back of the instrument panel as shown in figure 10 3 on page 151 Fig 10 2 Testing battery power to the tachometer This test is to determine if the instrument is getting voltage to run My red meter lead is connected to the gauge terminal marked IGN which will usually have a purple wire at tached My multimeter s black lead is connected to a com mon
363. pe psc os oes pss ps ps To 383 s oes e oe e ae er oe To n n o s zo s os oer o9 T9 po or oo oe om o om ooo Lo pem pe pepe pe f ee pers sse pem e pepe pm pep pe pue ec e ene es pm 9 Due par pee pee e mr pn Mre pee poa pne D n Ese oer Der e ps n poe e Dee pen e er oe Outside engine spaces OS zInside engine spaces IS Fig 11 4 ABYC ampacity table for a bundled run of up to three triplex cables ABYC tional consideration is whether or not they need to be of the single or double pole configuration Almost all circuit breakers used with DC systems are single pole breakers with two terminals on the back de signed to be connected in series with the DC positive feed wire A notable exception is with some DC panel master breakers where two single pole breakers will be ganged together For all AC circuits the main circuit breaker must be of the double pole type With this type the breaker will have four terminals and be designed to simulta neously trip both the black AC positive conductor and the white AC negative conductor This added safety measure provides protection even with reverse polarity So in effect even if the wiring entering the boat from the dock is set up incorrectly the breaker will still do its job If your boat s AC distribution panel is equipped with a reverse polarity indicator you may use single pole breakers for any branch circuits on the panel or downstream from the pane
364. peed Again verify the specification in your engine manual Make sure to check all the trigger coils if your engine is equipped with more than one Testing the CDI Unit Next using the multimeter and DVA adapter test the CDI unit for voltage to each of the high tension coils Be sure the ground wire for your CDI unit is se cure as damage to the module could occur if it s not Use this ground to attach the black probe from your multimeter DVA combination It s a good idea to use a wiring diagram to locate the stop circuit ground lead for your ignition module and disconnect it from the stop circuit this isolates the CDI unit from that circuit and eliminates the possibility that a defect in the stop circuit could cause you to misdiagnose your CDI unit as faulty Next switch your meter to a scale that will read about 400 volts or allow it to self scale Locate the high tension coil primary feed wire which is the wire that runs from the ignition module to the coil Attach the multimeter s red probe to the terminal on the high tension coil and crank the engine Your reading here which should be somewhere between 150 and 350 volts is the discharge from the capacitor inside the ignition module Match your reading to factory specifications for your engine Do this test on each lead coming from the CDI unit Your readings should be approximately the same for each one If you discover a lead with no output or a considerably lower output ch
365. percent of the total rating of all the breakers on the panel the conductors feeding the panel can be protected at up to 150 percent of the amperage of the feed conductors If the main panel has no master circuit breaker the fuse or circuit breaker for the feed wire may not be rated at more than 100 percent of the conductor ampacity This means that you must be sure the breaker protection and the wire size are appropriate for any additional circuits you decide to wire into the existing distribution panel on your boat To determine if a wiring upgrade feeding your panel is needed get the AWG size for the positive feed and DC negative ground lead from the insu lation and use the ampacity table in figure 4 7 to see if you need to make any changes Color Coding and Wiring Diagram Any wiring you add to your boat needs to be properly identified Color coding in accordance with the ABYC standards can help identify the function of in dividual wires but you should also draw up a wiring diagram of the circuit you ve added and put it with the other paperwork in your boat s information package If you already have a master wiring diagram making an addendum to it now will make life a lot easier three seasons down the waterway when the new circuit starts to act up For a list of recommen dations on alternate wire identification refer to chapter 4 Once you deal with all of the above you re ready to install your own DC accessories Some commo
366. plug wires resistance values are given in work shop manuals so you have a specification to work with In these cases use your ohmmeter to test for faults within the components by matching readings to the specifications On non self scaling meters you ll have to select the appropriate ohms scales Even self scaling auto ranging models can be a bit confusing Some meters give a direct reading with the decimal point placed exactly as it should be but others have a high or low scale and require some mi nor interpretation to place the decimal Read your multimeter s instructions carefully to be certain you have a clear understanding of how this scaling works on your meter Actual tests on ignition components as well as other ohmmeter tests where specific resistance values are important will be illustrated in chapter 7 So as we close out chapter 3 remember the tips given here and carefully select the best multimeter you can afford Your meter is a long term invest ment and unlike today s computer it will never be obsolete Volts amps and ohms haven t changed one bit in over a century However some of the latest Selecting and Using a Multimeter Figs 3 18 3 19 3 20 Sequence diagram showing a circuit with continuity and some resistance on a meter the same circuit showing a break or open and the OL reading on the meter and the same circuit showing a short and a typical meter reading Fig 3 18 Continuity
367. ply the circuit Voltage Drop Voltage drop is simply the reduction of voltage in a circuit caused by amperage working to overcome re sistance and represents the conversion of electrical energy to some other form of energy For example when you turn on a bilge pump the current amper age used by the pump converts the power wattage to mechanical energy that turns the impeller of your pump and keeps your bilge dry In another less desirable example when current encounters resis tance ohms in a circuit caused by wiring that is too small or by corroded terminals the wattage is con verted to heat wattage is more properly called joules here that can blow fuses and trip circuit breakers In extreme cases it can destroy your boat In both cases the reduction in voltage from the beginning of the circuit at the positive terminal of the battery to the end of the circuit at the negative ter minal is called the voltage drop Normally voltage drop is referred to as a percentage that we get by di viding the original voltage into the amount of the drop Thus a circuit measuring 13 5 volts at the pos itive terminal and 12 volts at the negative terminal we will discover how to make these measurements later on will be experiencing a 1 5 volt or 11 1 per cent voltage drop Putting It All Together Some basic facts relative to what happens to resis tance voltage and amperage as they are dispersed throughout the different circuit typ
368. point use the red probe to check the other points along the circuit The voltage at point 1 should be very nearly the same as your di rect reading across the battery If it isn t there is a bad wire or broken connection between the battery and the terminal at point 1 This test illustrates how battery voltage gets to the hot side of the starter button usually via a red wire If the voltage is good here proceed to point 2 Disable the ignition to prevent the engine from starting as you do the next four tests Press the starter button while holding the red probe to point 2 the output side of the starter button You should find a reading of approxi mately 12 volts If you don t your starter harness plug Battery Electrical junction Engine ground Fig 8 6a A typical outboard engine starter motor circuit with remote control button is defective and will need to be re placed Neutral safety switch MUN e CD Starter motor grounded to engine Engine ground point n Fig 8 6b An outboard engine with integrated starter motor circuit and no remote control Starter motor I grounded to engine Neutral safety switch S pushbutton Engine ground point Fig 8 6c Using a voltmeter to check the outboard integrated starter motor circuit Use the voltmeter to check voltage at each point indicated in the circuit 129 130 POWERBOATER S GUID
369. point two places to the right and you ll have found the percentage of drop in that particular circuit Depending upon which category the circuit falls into the drop must be less than 3 percent or less than 10 percent If you get more than the 3 percent or 10 percent limit the circuit has excessive voltage drop which is probably caused by wiring that s too small for the length of the circuit or a loose or corroded connec tion You must now trace the exact fault The next voltage drop test will isolate the drop between the positive conductor and the negative con ductor of the circuit Figure 3 7 on page 34 shows voltage being checked at the back of a typical distribution panel Figure 3 8 on page 34 shows the meter connections at your multimeter and correct meter attachment at a variety of typical bulb holders Measuring Voltage Drop Method 2 The second method for checking voltage drop is sometimes difficult for the beginner to understand The meter will be connected in parallel but you won t attach your lead probes to separate positive or negative conductors Instead attach both your probes to the same conductor or between a terminal in the circuit and a terminal on the appliance you re POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS ima 34 Fig 3 7 In checking source voltage at the back of a switch panel remember to always verify your power source first when tracing circuits testing Sometimes you ll
370. ps When I am working on any of these components I prefer the ca pability of measuring amperage to values as high as 600 amperes The less expensive meters that only read amper age in the milliamp range usually up to about 500 milliamps are fine for electronic work but they are useless for onboard amperage readings Slightly more expensive meters will often read 10 or some times as high as 20 amps but they require that the circuit be broken for connection of the meter more on that later Some meters that have a limited amperage scale can read higher amperage using a shunt a large low value resistor that bleeds a tiny amount of current off a high amp circuit so that a low amp meter can read it Shunt meters are complicated to use and difficult to read and so they aren t really a consideration for us However you re likely to find shunts perma nently wired to the alternator circuit on boats that use amp gauges with high amperage alternators Inductive Pickups If you ll be working a lot with high amperage DC cir cuits such as on a starter motor electric windlass or alternator you ll need a meter with an inductive pickup These look just like a normal meter with a huge crab claw like clamp on one end To measure voltage and resistance with an inductive pickup meter you use probes just like on a regular meter The only difference is in the way you measure amperage With a regular meter you must break the circuit on which yo
371. quency Hertz Hz alternator A machine that uses the principle of magnetic induction to produce electricity Alter nators produce AC which must be rectified to DC to recharge onboard batteries ammeter A meter used to measure the current flowing through a circuit Conventional meters must be hooked up in series with the circuit Modern inductive style meters simply clamp around a wire in the circuit ampacity The amount of amperage an electrical conductor or device can safely conduct ampere The unit of measure for electrical current or rate of electrical flow past a point in a circuit One ampere is equal to one coulomb 6 24 X 10 to the 18th power of electrons passing a given point per second Amperage is the stuff that trips circuit breakers and fuses and if not controlled can burn up your boat amp hour A current of one amp flowing for one hour a measure of the electrical energy stored in a battery anode The more positively charged electrode in an electrical cell average responding multimeter A meter whose voltage and amperage readings are calculated with an averaging formula battery An electrochemical device that produces voltage or a voltage differential across its terminals battery bank A group of two or more batteries linked together electrically battery combiner Electronic voltage sensitive switching device for automatically combining and separating batteries battery isolation switch A mecha
372. r at all times except when testing for voltage and amperage at points throughout the circuit 4 Never work on a system with wet hands or feet or when any of the components are wet 5 Make sure the boat is connected to a proper and tested ground even when working with the power off This means that whenever possible you must avoid working on AC when the boat is at anchor or on a mooring 6 Always wear rubber soled shoes deck shoes and running shoes are fine when working on AC power It s also an excellent idea to wear rubber knee pads because most of your work on a boat will be done while kneeling 7 Never work on AC service with distractions such as a television or chatty friends present 8 Ground fault circuit interrupters GFCIs should be tested at least monthly to ensure proper func tion The common practice of clipping off the third prong the grounding prong of a three pronged plug creates a real shock hazard on board a boat and this should never be allowed Any cords or equipment you have where this all important ter minal has been removed should have that third terminal replaced 10 Avoid doing obviously dumb things such as standing in water or putting hot wires in your mouth when working with AC Let s take a more detailed look at specific system layout and the key standards as established by our friends at the ABYC Color Coding for AC Wiring Unlike the DC systems already discussed we wil
373. r resistance or ohms Fig ure 1 8 on page 8 shows the simple equation used to find watts or amps if voltage and wattage are given Electrical Basics You Need to Know AMPS Fig 1 7 The Ohm s law equation This circle provides a visual relationship between the key electrical players If any two of the values are known the third can be found by using either multiplication or division By multiplying amps times ohms voltage can be found By dividing voltage by ohms amperage can be found Dividing volts by amps determines resistance ohms Notice that if voltage remains constant and if resis tance increases reduce amperage flow and vice versa This explains mathematically why a short circuit to ground before power reaches a load resistance is so dangerous Amperage will go way up until either a fuse blows or a breaker trips or something burns up Conversely it also explains why if resistance increases loose connections too small a wire amperage needed by the appliance won t be delivered Ohm s law works out rather nicely for us as boaters because we will always be able to measure at least two of the values we need to calculate the third Voltage V and amperage A are both easily mea sured using a basic multimeter and we will learn how to do this later With some circuits ohms R area little tricky to measure accurately but we ll learn how to handle them also For our purposes wattage W is not measured but calculat
374. rating of the pump you ll need based on the volume of the area the pump will ser vice the height from the base of the pump to the point of discharge and other factors With bilge pumps depending upon several vari ables the actual amount of bilge water the thing will move overboard will vary considerably from the rat ing embossed on the pump Aside from mechanical variations in pumps you ll need a circuit with a 3 percent maximum voltage drop if you re going to get anything close to the rated output of the pump Ex cess voltage drop here will affect pump motor speed and the volume of water it will move According to the ABYC and the chart in figure 2 5 on page 16 a bilge pump circuit should have a brown positive wire and either a black or a yellow ground return wire is acceptable Because this load is a 12 volt motor the bilge pump must be protected with a fuse rated at no higher than the manufacturer s recommendation In my own tests I have experimented with fuses as lit tle as 1 5 amps over the rating recommended by the pump manufacturer In these tests I locked the pump s impeller to simulate an actual installation and let the Cabin Light Cabin Light pump run Figure 9 2 on page 141 is a photograph of the result of one test As you can clearly see the body of the pump is melted away and badly deformed The wires feeding the pump on the other hand are unscathed Why does this happen Why is the pump itse
375. ration Insulating or moving away from excessive magnetism mega M Prefix meaning 10 to the sixth power or one million micro p Prefix meaning 10 to the minus sixth power or one millionth milli m Prefix meaning 10 to the minus third power or one thousandth As in milliamp or mil livolt multimeter tionality Electrical meter with multiple func ohm Q The unit of measurement of electrical re sistance ohmmeter A device that measures electrical resis tance Ohm slaw The mathematical equation that ex plains the relationship between volts amps and ohms open See open circuit overcharging Forcing excessive current into a bat tery Overcharging causes excessive battery gassing and loss of electrolyte a dangerous situa tion in either event open circuit A break in a circuit that interrupts the flow of current open circuit voltage The voltage reading across the terminals of a battery at rest with no charge going in and nothing drawing power from it overcurrent protection device A fuse circuit breaker or other device installed in a circuit and intended to interrupt the circuit when the current flow exceeds design ratings overrating Applying more voltage or amperage to a device or component than it was designed to take panelboard Electrical distribution panel Includes branch circuit breakers or fuses and both nega tive and positive bus bars May also contain sys tem volt and amp meters
376. rator voltage and fre quency is not difficult but to ensure that any low voltage indications on your AC panel are not due to a wiring and voltage drop problem between the generator and the panel measurement should be done right at the output ter minals on the generator When check ing voltage and amperage at the generator be careful of moving parts and the hot exhaust on the generator and be sure to take your readings at the correct location as per the instructions Fig 11 22 Checking frequency with the multimeter AC Generator Troubleshooting Guide Aside from these basic checks some more advanced procedures are found in the following checklist These additional checks are too advanced for most beginners and will have to be carried out by a trained technician preferably one certified on your particu lar brand of generator Low Voltage gt Check the voltage at the generator If the reading is OK and your panel meter is reading low there is an excessive voltage drop in the wiring between the generator and the panel em Verify correct generator engine rpm and governor settings gt Check all connections and wire terminations for integrity First make sure the generator is off em If voltage is OK until the engine warms up and loads are applied the generator voltage regulator and related circuitry are at fault gt The voltage regulator may need adjustment or re placement High Voltage gt Check
377. rcuit is to trace the circuit while checking for voltage drop at various points This test will be outlined in the following section on outboard engine starter circuits and will work just as well for inboard engines uthoard Engine Starter Circuits A system overview of a typical starter motor circuit on an outboard engine with remote control is shown in figure 8 6a on page 129 On many engines the re mote control harness plug is located under the en gine cowl so this plug is not as shown in the diagram If your outboard engine doesn t have a remote ig nition switch it will have a starter button located on the engine and may have a neutral safety switch in tegrated into the mechanical shift linkage under the cowl A simplified wiring diagram of this circuit is shown in figure 8 6b on page 129 Your engine may have some of these connections in a wiring junction box Also starter motor battery terminals are often used by manufacturers as handy places to attach ad ditional circuits so refer to your wiring diagram and narrow the number of wires down to what you see in this drawing ignore the rest All outboard engines use inertia type starter motors that engage the flywheel ring gear when centrifugal force throws the drive gear upward Medium to large outboard engines also use a re motely mounted solenoid just like those used on in board engines Problems with inertia systems can be as simple as a low battery or corroded terminal
378. re 137 panel feed wire 138 voltage drop and wire size 137 voltage requirements 136 wire type 137 wiring diagram 138 direct current DC circuits amperage draws for onboard equipment 37 compared to AC circuits 159 62 distribution panels 52 55 56 137 160 182 183 See also master distribution panels distributor caps 101 maintenance of 107 8 distributorless ignition systems DIS 102 3 distributors 101 2 double pole AC circuit breakers 163 164 draw test 94 dual battery installation 57 58 79 81 DVA adapter 115 116 18 117 Ed Sherman wiggle test 169 170 electrical circuits See circuits electrical potential 6 electrical symbols 13 electricity 1 electrolyte 65 72 73 83 84 97 electronic equipment heat sinks 144 installing 180 92 electronic ignition systems See ignition systems end strippers 11 62 143 engine ground 91 128 29 engine ignition switch 133 35 134 203 204 engine instrumentation abnormal readings 148 49 future equipment 155 interpretation problems 147 48 troubleshooting 149 55 engine mounted circuit break ers 91 engines See diesel engines igni tion entries outboard entries starter motor entries engine stop control 112 equalization phase 96 98 extension harness 132 33 F ferro resonant battery chargers 96 97 field excitation voltage testing 92 93 field windings 86 fires 78 fish finders installing 186 90 187 188 189 troublesh
379. re safely find that elusive lunker fish or communicate with fel low boaters or friends on shore Installing Your Own Electronics Most aftermarket electronic accessories for boats are expensive some such as new radar or that video camera mentioned above are very expensive But one of the best ways to reduce the financial shock of new electronics is by doing the installation yourself 180 Fortunately this is a fairly easy task and with the never ending advances in equipment the immediate results can be quite gratifying provided you take into consideration certain factors that ensure a proper installation Universal Installation Details Depending on whether you re installing a depth sounder a fish finder a VHF radio a GPS receiver or radar many of the nuances of installing new elec tronics will vary but the basic procedures for most new equipment are similar with certain considera tions in common magnetic fields radio frequency interference RFI and the power supply Let s take a look at these three items one at a time Magnetic Field Issue One thing that is often taken lightly but is of extreme importance is the initial decision of where to mount your new equipment Besides the obvious ergonomic considerations of seeing the screen or controls on the new device and perhaps keeping it from getting sprayed with water while underway stray magnet ism is a major concern Today s small powerboats have relatively
380. reakers for feeder wires from the shore power inlet on your boat to your main AC distribution panel Refer back to chapter 4 to refresh your memory re garding the 7 40 72 inch location rule and the 100 150 percent rule The ABYC allows a run of up to 10 feet between the shore power inlet and the main circuit breaker on the main feed conductors to your boat s AC distribution panel On boats of the size for which this book is intended up to about 35 feet this will usually mean the main breaker will be located on the AC distribution panel itself For larger installations where the distance between the inlet on the boat and the panel exceeds 10 feet a circuit breaker is required on the feed wire before it reaches the panel These breakers must be of the trip free va riety just like those used for DC so they can t be held closed by the operator This means you must use only marine rated circuit breakers for any replacements to existing services as well as for any new circuits AC Circuit Breaker Types Circuit breakers for use with AC systems must be of the trip free variety as already stated But an addi Alternating Current and AC Equipment TABLE VIII C ALLOWABLE AMPERAGE OF CONDUCTORS WHEN 4 TO 6 CURRENT CARRYING CONDUCTORS ARE BUNDLED TEMPERATURE RATING OF CONDUCTOR INSULATION 128 C 200 C CONDUCTOR 257 F 392 F n i i 2 MM AWG OR Is so ss so ss spe s us 5 us 59 9 59 L pep psp
381. represents the conversion of some of the DC to heat as it s inverted Typically inverters are about 90 percent efficient so you can expect to lose about 10 percent of the available amp hours from your supplying battery bank through the in verter That and the fact that you really don t want to discharge even the best batteries much below 50 percent of their capacity should tell you that you re going to need some serious DC capacity i e big batteries to make this all work as it should Figure 11 17 on page 172 shows a typical amp hour calculation table that should be used to deter mine total amp hour consumption between battery charge cycles when plugged into shore power Once you have determined your daily amp hour requirements you need to think about how many days you might be away from shore power and how frequently you ll be charging your batteries with the 171 172 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Wattage Calculation Worksheet Appliance Rated Wattage Start up Wattage Use this table to list all of your AC appliances Find out the wattage by checking the UL labeling on the appliance Startup wattage applies to appliances such as refrigeration devices refrigerators ice mak ers air conditioners In the case of inverters the medium to larger sized units all have an intermit tent output rating that s usually more than twice the rated continuous output in watts this is to al low for the ne
382. rers connect a series of six cells which each produce a little more than 2 volts to attain the 12 volts in batteries used by most boats Larger boats might use 24 volt systems and some boats even use a combination 12 and 24 volt system but these are just 12 volt batteries connected in series to get the higher voltage When battery cells are connected in series the voltage is multiplied Thus multiplying the number of cells in a lead acid battery by two gives the final system voltage If we hook these cells or batteries up in parallel the voltage stays the same but the am perage of the system is multiplied Thus if you have two 6 volt batteries with 25 amps each wired in se ries you ll end up with a 12 volt bank having 25 amps of current available If you wire these same two batteries in parallel you ll have a 6 volt system with 50 amps of current available The majority of recreational boats today oper ate on 12 volt battery systems so we ll stick with those Figure 5 8 shows two pairs of 12 volt batter ies One pair is connected in series the other in par allel and the resulting amperage and voltage of each arrangement is shown This is very important I ve seen more than one boater trying to connect bat teries in the spring and they just can t remember how they were attached when they took them out Here s a quick tip to prevent this confusion Sim ply mark the cables when you remove your batteries in the fall so you
383. ressure then it should be easy to think of amps as the volume of electrical energy flowing through a point in a circuit Amperage is most im portant in my mind because too much of it in a cir cuit is what trips circuit breakers blows fuses melts wires and other components and sometimes burns up boats This stuff needs to be carefully controlled and much of the rest of this book will be devoted to understanding how to do just that Resistance Resistance as we said is measured in ohms and is that invisible force that holds back electrical flow amper age and reduces the electrical potential voltage as electrical energy flows through a circuit It s also the electrical unit that puts electricity to work for us For example it s the resistance in the element of a light bulb or the toaster in your kitchen that makes the el ement glow and give off light or toast your bread And it is the rapidly fluctuating resistance in micro scopic transistors measured in tiny fractions of an ohm that makes the wonderful world of marine electronics possible In marine wiring unwanted or excessive resistance is caused by such things as loose or corroded connections wire that is too small in diameter or wire runs that are too long One noticeable by product of resistance to elec trical flow is heat In the case of the toaster we have engineered a way to make this heat useful In the case of a loose or corroded connection the heat generated
384. ring Yeah but what does it do Why do I need one If you spend much time at the dock plugged into shore power you need a galvanic isolator Here s why Galvanic current flow is a danger at any marina putting your boat at risk of galvanic corrosion The more boats with AC shore power the greater the risk Your boat could be in great electrical shape but once plugged into shore power it becomes elec trically connected to its neighbors via the green grounding wire in the AC system This connection completes an electrical circuit between multiple boats each with potentially dissimilar underwater metals exposed to the surrounding seawater What s created is a giant battery and the potential galvanic corrosion that can result Further it is also possible to transfer higher voltage DC stray current from one 177 178 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS boat to another in this situation This could generate stray current corrosion How can that be You might have thought the AC and DC systems were completely separated on your boat They are except for one common point where the DC and AC grounding system are tied to gether Any faults that induce current flow in this normally non current carrying conductor can po tentially be transferred via this green wire This stray current can cause excess corrosion rapid deteriora tion of underwater sacrificial zincs and in the worst case can cause underwater metal appendages from
385. roblem with this circuit is that as electrical current flows through each load it s doing work for us making a light bulb glow for example and each of the loads in the series circuit must share the available power So the available volt age at the source in this case the 12 volt battery gets divided by each ofthe loads In the example shown in figure 1 3 assuming that each of the light bulbs has the same wattage the voltage drop across each bulb will be one third of the available 12 volts or 4 volts each Thus if the bulbs are engineered to run on a 12 volt source each will glow more dimly than designed passing through the hull causes all sorts of problems the most important of which is severe corrosion Thus nearly all marine acces sories will have two leads and the second wire com pletes the circuit back to the battery Also the best ma rine accessories are heavily constructed of noncorrosive materials and are designed to function in the hostile marine environment OK now that we under Battery Circuit Protector stand the differences between Fig 1 2 A simple series circuit with only one load POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Battery Circuit Protector Switch On A Cabin Light Cabin Light speak for a broken circuit the other appliances can carry on with their jobs Parallel circuits are clearly superior to series circuits any time multiple
386. roubleshooting Starter Motor Circuits 000 125 Outboard Engine Starter Circuits 0 e eee ee eee 128 Testing the Neutral Safety Switch 00 eee eee 132 Engine Ignition Switch 00 cece eee eee 133 Other Outboard Engine Starter Motor Problems 135 Chapter 9 Installing Your Own DC Accessories 136 Before You Begin serr errit titr retur x Sin male rb dr URS 136 Installing a New Cabin Light ccc eee eee 139 Installing a New Bilge Pump 0 0 cece cece eee eee 140 Adding a New Compact Disc Player 000008 144 CONTENTS 22 Chapter 10 Engine Instrumentation Problems and Solutions 147 Mechanical Gauges isses serene eh ee newer eee 147 Common Instrument Interpretation Problems 147 Abnormal Instrument Readings 00 0 c eee ee eee 148 General Instrument Troubleshooting 00 149 MDS PU MPO Ds 155 Chapter 11 Alternating Current and AC Equipment 156 What Is Alternating Current 0 c cece eee 156 AG on Your Boat coerente naw et bes ERREUR wees 157 AC Safety Dnm 157 Color Coding for AC Wiring 0 00 cece eee eee eee 158 Comparisons between AC and DC Circuits 159 AC Overcurrent Protection 00 162 Basic AC Outlet Connections 0 00 00 e cece ee eee eee 164 Ground Fault Circuit Interrupters 0 000
387. rrent was getting to the plug the plug must be replaced If it s a standard plug check the gap before installing the new plug as shown in figure 7 11b on page 112 Sur face gap plugs require no adjustment Spark plugs are among your most valuable diag nostic tools Whenever you remove your plugs keep them in order for the cylinders they came from Check each plug carefully look for cracks in the ce ramic insulator body black oily buildup or discol oration on the electrodes A spark plug that s burning correctly will show a light brown fluffy coloration on the center electrode and a fluffy black coloration on the metal base The ground electrode will be a light gray brown color One last thing regarding spark plugs be careful not to over torque when reinstalling them into the cylinders It s a good idea to put a light coating of white grease on the threads before screwing the plugs back into the cylinder head Screw them in by hand until the sealing washer seats then use your spark plug wrench or a socket and ratchet to tighten them an additional half to three quarter turn Any more torque than that could damage the plug threads in the cylinder head You should never replace just one plug Replace them in sets and don t bother saving the old ones for use as spares They actually make good sinkers for offshore fishing You should always have a fresh set of gapped and ready to go plugs on board your boat just in case Igniti
388. rrosion and any signs of carbon tracking One problem with the Thunderbolt system is that this rotor is attached to the distributor s center shaft with a product known as Loctite As the name im plies Loctite is a kind of glue that secures the rotor to the shaft Unlike most rotors that simply lift off the shaft against the pressure of a small spring clip these rotors are on tight Don t expect to simply lift it off for inspection To remove the rotor place two flat bladed screw drivers under the rotor at its base and push them Fig 7 6 Carbon tracking inside a distributor cap These tracks provide a highly conductive path for your ignition voltage to short circuit between cylinders snugly up against the distributor shaft The screw drivers should be at 180 degrees from one another Push both screwdrivers down against the distributor housing and hope the rotor pops off If this doesn t work use an electric hair dryer on high heat and fan the rotor and sensor wheel until they begin to feel warm to the touch Try prying again but don t bend the sensor wheel blades The slightest distortion of the wheel will render it useless so alignment of the blades with the sensor inside the distributor is criti cal With diligence the rotor will eventually lift off Once the rotor is removed carefully inspect it for carbon tracks and any damage to the key inside the center section Replace the rotor if there is any dam age
389. rs A blown fuse or a tripped circuit breaker on a starter motor circuit could be caused by a partially seized starter motor or in the worst case a seized engine both of which situations will be covered in more de tail later on in this chapter If all connections and fuses or breakers appear to be in good order a faulty part is certainly the cause for your starter circuit grief and a step by step approach will be needed to determine which part is at fault Starter Solenoid Most marine inboard engines have a remote solenoid sometimes called a slave relay A solenoid is used as a remote switch to control a circuit such as your starter circuit that carries heavy amperage Acting as a shortcut the solenoid is connected to the starter switch with a smaller wire to save on the amount of heavy wiring needed to operate the starter circuit In other words instead of having a cable as big as your thumb running from the battery to the ignition switch and then from the ignition switch to the starter motor the heavy cable connects directly to the starter motor through a solenoid The solenoid is op erated by a much smaller usually 10 or 12 AWG wire that connects the solenoid to the ignition switch Many starter circuits use a solenoid as a remote relay that does not carry full starter motor current To determine if your solenoid is intended to carry starter motor current first locate the solenoid It s generally cylindrical and is ofte
390. rs of outboards also install a fuse in the circuit so check your owner s manual The last component in this basic system is the battery A common question regarding unregulated sys tems is whether they can be run without connecting the motor to a battery without damaging the stator rectifier The answer is that it depends Some mo tors can be run without batteries and some can t Follow the recommendations in your owner s man ual Some manufacturers provide caps to cover the Battery Charging Systems Stator windings Fig 6 11 Unregulated outboard charging system battery cable terminals to prevent them from touch ing while the engine is running without a battery However some companies Mercury for example also recommend disconnecting the stator wires from the rectifier and insulating them from each other if you re going to use their motors without a battery Figure 6 11 illustrates a typical unregulated out board charging system Testing the Unregulated System From years of experience I can tell you that the boat owner causes 99 percent of the problems that occur with these unregulated charging systems Rarely is there any trouble with the permanent magnets or the stator windings under the flywheel Problems are al most always due to corroded or loose connections or to a failed rectifier As I ve mentioned before diodes are very sensitive they hate it when battery wires are crossed or grounded unexp
391. s 1 9 s 70 as 70 amp ss 319 os as 7 sse 70 s 9 ono s0 sor 9 s a5 o aca os ns 1o 7 16 320 12 12 25 nr 55 a a uos ss as sss 130 vor is no 160 6 170 isr 189 2 65 io uz me ur s us 6 wr 26 i78 22s 26 296 000 81 260 310 232 330 2 0000 103 380 270 385 3 00 NOTE Cross reference with voltage drop tables in figures 4 3 and 4 4 90 C 105 C 125 C 200 C 194 F 221 F 257 F 392 F Fig 4 7 Table IV from section E 11 showing the allowable amperage of conductors for DC systems under 50 volts ABYC damage anything Fuses are simple devices but to avoid problems with them there are some important things you should know Fuse Types and Ratings Popular fuse types shown in figure 4 8 include the cylindrical glass bus type fuse designated as AGC the newer and increasingly popular blade type fuse des ignated as ATO and a heavy duty slow blow fuse designated MDL or type T There are many fuse des ignations other than AGC ATO and MDL but these three are the most common and will do for our purposes The most important specification to look for when selecting a fuse is the amperage When selecting a fuse for a circuit base the size of the fuse on the cur rent carrying capability of the smallest wire in the cir cuit For example if you select a 14 gauge AWG wire to get power from
392. s VDO and MerCruiser for example offer sending units designed for two gauges for use on dual helm boats Any discrepancy between the two gauges working on a common sending unit is caused by voltage drop the phenom enon mentioned throughout this book Since you have read this far you know that due to the in creased resistance to electrical flow in a long wire the length of a wire has a direct effect on voltage drop Well this extra resistance directly affects the instrument reading at your console because most instruments rely on variable resistance created by an engine mounted sensor to give you readings Differences in the lengths of connecting wires on instruments at upper and lower stations combined with manufacturing tolerances in gauges and sensors ultimately control the actual reading you get at your instruments Don t panic if you see slight variations from one gauge to another This is a normal condi tion and repeated trips to your mechanic or boat dealer to solve the problem will almost always prove futile Remember to look for relative changes in your normal instrument readings that s what s important Abnormal Instrument Readings At some point your instruments will indicate that a condition other than the norm exists It might be high engine temperature low oil pressure erratic rpm or dozens of other deviations from your normal readings Often when there is a change in one instru ment there is a corresponding chan
393. s causing a cranking speed that s too slow to gener ate enough inertia to engage the drive gear So as with any system the first thing to check if trouble develops is the battery and all its connections The open circuit voltage test described in chap ter 5 will show you if the battery is fully charged If it isn t charge the battery to bring it up to snuff be fore proceeding with any of the following tests Of all the electrical circuits on your boat the starter circuit is probably the one that draws the most am perage until the engine starts the starter motor needs all the juice the battery can give it After you make sure your battery is fully charged it s time to trace circuits To test the integrated system found on small engines without remote control first check for voltage at points throughout the circuit Fig ure 8 6c on page 129 shows the points to check and the sequence in which you should check them Make sure your engine ground and the ground bolt or cable it should be the black one are free of corrosion and tight Tracing and Repairing Starter Motor Circuits Battery ground cable Starter motor Solenoid Remote control with key switch and neutral safety switch Remote control Positive cable At point 1 check the power to the push button switch With your meter s black probe attached to an engine ground the bolt or cable grounding the starter motor to the engine is a good
394. s tilted up out of the water timing Engine s ignition timing Point at which the spark plug fires in a cylinder transducer Two way sender receiver used with depth sounder GLOSSARY transformer An electrical device consisting of two or more coils used to magnetically couple one cir cuit or section ofa circuit to another Transform ers come in three basic configurations one to one where voltage on both sides of the transformer primary and secondary stays the same step up where the voltage is increased from the primary to the secondary side of the unit and step down where the opposite occurs trigger coils Used to send an electrical charge to a CDT s control box to tell it which cylinder to fire next trim gauge Used to indicate relative IO drive or outboard engine trim angle trip breaker To open the circuit trip free circuit breaker A breaker designed in such a way that the resetting means cannot be manually held in to override the current interrupting mechanism underrating Not having adequate ampacity See also ampacity ungrounded conductor A current carrying con ductor that is insulated from ground Often thought of as the hot wire in a circuit volt The unit of voltage or potential difference from one side of a circuit to another voltage drop The loss of voltage as it works its way through a circuit Excessive voltage drop indi cates unwanted resistance in a circuit or circuit component
395. s a great idea you probably won t have ready access to a set of quality shop gauges The tips that follow will help you around this deficit and to successfully solve most instrument problems Remember if you still have doubts about your abilities to attack your instrument problems after reading the steps outlined here your best bet is to call ina pro who has the equipment to do the job properly 149 150 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Troubleshooting the Tachometer Tachometer circuits come in several types depend ing on the engine used in your boat The primary differences are between those used on gasoline and on diesel engines Modern diesel tachometers are generally connected to the back of the engine alter nator at a terminal labeled tach This terminal senses the AC pulses inside the alternator and sends them to the tachometer where the pulses are trans lated into engine rpm The tachometer on most gasoline engines gets its signal from various points in the ignition system The only way to be really sure where your tachometer is getting this signal from is to use your wiring diagram and service manual On gasoline engines the sens ing wire is usually gray If there is any break in this wire between the ig nition circuit and the back of the gauge the tach ometer will not give a reading Any short circuit in this wire can short out the ignition system and cause the engine to quit Figure 10 1 sh
396. s is coming through with at least a rudimentary AC system Boaters now demand onboard systems to run a shore power fed battery charger and electric hot wa ter In New England where I live small boats might have an electric space heater in the cabin Even 23 to 27 foot long walk around fishing boats and weekenders on which designers wouldn t have dreamed of installing an AC system just 10 years ago now have several outlets in the cabin as standard equipment Boaters are demanding more of the comforts of home and builders are doing everything they can to oblige the craving for luxury With all of this in crease in AC equipment on boats comes the need to have a basic understanding of how alternating cur rent works and how it gets integrated into your boat s total electrical system AC power will come on board your boat from one of three sources a di rect plug to shore an AC generator or a DC to AC inverter Since both the AC and DC systems are run closely together throughout your boat you need to make sure you know which system you re work ing with and how to identify the key components of each system Never forget that alternating current can kill you AC Safety Alternating current can be extremely dangerous if it s not handled with care and common sense The haz ard of a lethal electrical shock is real and present any time you have AC on your boat and a poor quality AC installation is as much of a fire hazard as a bad DC i
397. s must be followed p gt Install the scanner on your cabintop or on an ap propriate mast with a platform designed to ac cept the mounting bolts p gt Position the scanner so that the antenna gets a good all around view with as few parts of the su perstructure or rigging as possible intercepting the scanning beam Any obstructions will cause shadows and blind sectors on the radar screen To minimize electrical interference don t route the cabling from the antenna near any other on board electrical equipment or cabling just as with other gear mentioned above Remember that a radar antenna creates pro nounced compass deviation Keep a separation zone of about 5 feet 1 7 m between the radar antenna and your compass When installing an antenna on a powerboat consider the average angle at which your boat cruises while underway If the antenna is mounted perfectly level with the boat at the dock it will tend to aim at the stars while underway Figure 12 15 il lustrates the static angle for the antenna and the ef fect this slightly downward mounting has on the beam while the boat is underway To determine the exact angle of the antenna to use spend a morning determining the amount of lift your boat goes through from a standstill to cruising speed Once 181 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS 192 Fig 12 15 Static angle for powerboat radar antenna installation you have establi
398. s series of tests you ll know for sure whether you need a new battery or not It may sound like a lot of effort but really these tests can be performed in less than half an hour I don t know about you but I d rather spend half an hour than 75 to 400 for a new battery Chapter 6 Battery Charging Systems In the last chapter we went into some detail on the various types of marine batteries and how to main tain and install them However the most crucial concern of battery performance isn t installation or maintenance although these two procedures are certainly important enough but in the method and extent to which they are recharged once they have been depleted to acceptable levels A battery that s regularly overcharged is going to shed material from its plates and boil away its electrolyte dooming it to a tragically short and ineffective life A battery that s regularly undercharged is going to have its plates choked with impenetrable and indestructible lead sulfate and is likewise doomed to a premature trip to the local recycling station The three types of batteries we have discussed so far wet cells gel cells and AGMs respond to charging in different ways but they are all very par ticular about how they get their electrons reener gized Batteries must be recharged just so and if you don t do it right you as a boatowner are going to be making a lot more trips to the battery store than you need to make There are bett
399. s such as those found on incandescent lights toaster ovens and the like The problem comes when you try to measure current on a non linear load In effect this is any AC load that has some sort of solid state control Many air conditioners and refrigeration systems fall into this category Depending upon the AC feed shore power inverter or generator the error can be as much as 40 percent on the low side This error has se rious safety implications when you re trying to deter mine wire gauge and circuit protection ratings The simple solution if you can afford it is to buy the RMS meter if you re going to be working around AC current supplied by anything other than a shore power connection If your boat is equipped with shore power and has no inverter or generator the less expensive av erage responding meters will give adequate re sults The difference between the AC power created by an inverter or a generator versus a shore power connection will be discussed in chapter 11 Self Scaling No the self scaling feature doesn t have anything to do with cleaning fish if they ever bring out a multimeter that will do that I will be first in line to buy one Self scaling also called auto ranging simply means that once you select a function on your meter the meter will sense the magnitude of the function and set the scale accordingly This important feature takes the guesswork out of selecting the correct voltage resis tance
400. s will show low voltage when measured with an average responding meter This is no cause for alarm and not indicative ofa fault with the inverter Rating AC Generators AC generators are rated the same way in verters are Wattage is the key here and the basic AC use analysis chart for inverters will work just as well for determining your generator re quirements The essential difference between generator and inverter ratings is that typically generator manufac turers have rated their units in kilowatts KW One kilowatt equals 1 000 watts so for example if your generator is rated at 4 5 kW it s a 4 500 watt unit As with inverters boaters are inclined to over or underrate their needs with generators Underrating will give poor electrical performance for what should be obvious reasons by now But a point that many people don t realize is that overrating of a generator can wreak havoc with the generator itself Generators are designed to operate at a very specific rpm to gov ern and control the AC frequency They must be able to maintain this rpm over the entire operating range of the unit under all levels of electrical load The problem is just that load Underworked generators will simply freewheel along eventually gumming up the cylinders valves and rings ofthe en gine Slight overrating in terms of average combined wattage consumption is OK but manufacturers rec ommend that a generator be rated to average 75 per c
401. s without internal modifications to the alterna tor that must be done in a professional shop One wire alternators have been widely used by both MerCruiser and OMC Figures 5 12 5 13 and 5 14 show three typical multiple battery installations using the components described above Figure 5 12 shows a typical single engine two battery setup with a master switch and Alternator Battery Starter Motor Switch Solenoid Parallel Batteries Ground Stud on Engine Fig 5 12 Single engine two battery circuit with battery switch installed Remember that battery switches must be matched to the maximum expected amperage they need to handle Batteries and Battery Systems Alternator Alternator Engine 1 Parallel Batteries Fig 5 13 Similar arrangement with the addition of an isolator Alternator Alternator Engine 1 Battery OFF J Switch DN Parallel Batteries Fig 5 14 Twin engine installation with two battery switches and an isolator 81 82 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS COMBINED PN7610 120A SI ACR Automatic Charging Relay with Starting Isolation Typical 120 Amp SI Automatic Charging Relay Installation Switch Fuse Remote LED Start Key Starting Isolation Ground Optional Figs 5 15a b The Blue Sea System battery combiner no battery isolator Figure 5 13 shows a sim
402. scheme regardless of the length of the run or the anticipated load You can of course legally and safely use 14 gauge wire for your AC cir cuits as many builders of budget boats do but since the savings amount to about 30 for a 100 foot roll you might as well go ahead and use the heavier and slightly safer wire Tinned triplex with AC color coding black white and green is available from West Marine and most other chandlers I ve said it before and I ll say it again Don t use Romex or any other solid copper wire on your boat If you have any already installed replace it with proper boat cable As for the insulation temperature rating of AC wiring rated boat cable from a marine supply store will probably have a 105 C rating although there is still some 90 cable available and many boats already wired have this lower rated wire in use Figure 11 4 on page 163 shows the ampacity for a group of two to three of these triplex cables bundled together The higher ratings in the tables are specialty cables not readily available and the lower ratings are not commonly available either For any new work you re doing the 105 cable is more than adequate for typical small boat installations AC Overcurrent Protection As for rating and location in circuits of overcurrent protection devices fuses and circuit breakers the same basic rules apply for AC circuits as for DC cir cuits An exception is the rating and location of b
403. sed in rough conditions will have a 6 or even a 3 dB antenna for extra reliability while the boat is pitching and rolling The Coaxial Question Besides the effects of antenna placement and the power supply to your VHF you should also consider Fig 12 5 Wave patterns radiated by 3 dB 6 dB and 9 dB antennas the type of cable connecting your antenna to your radio Also when selecting an antenna look carefully at the factory lead coming from the base of the an tenna it should be of quality coaxial cable described below If not after reading this section you may de cide on a different antenna The coaxial lead should not be the only criterion used for antenna selection however Internal construction and a quality plated brass base mount are also considerations Coaxial cable coax is designed to conduct trans mitted and received energy between your antenna and radio Coaxial cable is a two conductor cable with a center that you can think of as the positive conductor The next outermost layer of typical coax cable is an insulation layer used to keep the woven ground conductor separated from the center conductor This outer conductor is sheathed by the outer skin of the cable Just as with any wiring on board the quality and amount of energy lost through this cable will affect the performance of the radio In this case the loss is measured in dB rather than the voltage drop mentioned throughout this boo
404. sender removed I m grounding it out on the en gine block with the ignition key in the on position the needle on the temperature gauge on the dash panel should read at the maximum side of the gauge 153 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Senders on metal tanks often have only one wire and the sender grounds to the tank itself Discon nect the wire and ground it on the tank In either case if the needle moves so that the gauge reads full the sender is bad and must be replaced In some instances fuel gauges work fine at some fuel levels and not at others This erratic reading is a function of the sender design and partial failure is not uncommon To check remove the screws hold ing the sender in place on the top of the tank and lift it out Next attach a jumper lead between the tank ground lead and the grounding connection on the sender Again with the ignition key on move the float on the sender up and down while carefully ob serving the gauge on your instrument console You may need an extra set of eyes to help you here de pending on the distance between the sender and the gauge If the needle on the gauge acts erratically as you move the float assembly up and down the float sender needs replacement Figure 10 8 shows a sender removed and being tested An important safety note here is to carefully inspect the condition of the gasket sealing the float mechanism to the tank If any doubt exists as to its con
405. several meters that they use regularly and it s not unusual for some gad get hounds to own four or five different meters A Few Specific Recommendations There are a few inductive meters with which I am personally familiar and can recommend as good choices for your first meter Ancor 702070 One excellent general purpose meter is the latest Ancor brand pocket meter see figure 3 2 page 30 with built in inductive pickup This meter doesn t quite reach my ideal of a 600 amp capability but on measurements of up to 200 amps in both AC and DC it does a fine job It also has the usual ability to mea sure volts and resistance and the less usual ability to measure frequency we discuss frequency or Hertz in chapter 11 Frequency measurements are useful for checking the output of shore power outlets Selecting and Using a Multimeter gt A Word about Inductive Pickups Induction is the phenomenon whereby an electrical current flowing through any material creates a magnetic field around the material For example a lightning bolt passing through the atmosphere can gener ate a huge magnetic field around it and every time Wile E Coyote grabs the wrong wire as he is trying to electrocute the Road Runner it s the induction induced magnetic field that makes his fur stand on end Because of induction any wire that has electrical current flowing through it will have a magnetic field surrounding it regardless of the insulation used a
406. shed this angle you ll know how many degrees to tilt the forward edge of your radar antenna downward for optimum scanner perfor mance while the boat is under way Typically this number is around 10 or 15 degrees The antenna has a definite front facing position that must be observed Follow the manufacturer s in stallation instructions if you re not sure how to achieve this important orientation Also as with the other gear mentioned the cable that comes with the radar is of a calibrated length that should only be altered to the approximate location of the display perma nently mount the display Again ergonomics is im portant Radar is useless if you don t have a clear unobstructed view of the entire display Connect the display to the dedicated instrument bus for positive and negative return run a ground from the back of the chassis at the wingnut and stud to the nega tive bus bar connect the antenna cable to the appro priate socket and you re ready to go Figure 12 16 illustrates the wiring hookups for a typical radar in stallation with some of the other mentioned con cerns pointed out in the diagram I have one last general note regarding electronic equipment Never attempt to use this gear until you ve read through the fine points of the owner s manual and documentation that comes with the equipment In most cases before the gear can be used effectively there is an initialization or preliminary tuning procedure th
407. shers that you find under the coil or the hold down bolts Misplacement of these washers can cause a no spark condition with a perfectly good coil Water Spray Test Another simple test for determining the integrity of your secondary ignition system is to run the engine and use a spray bottle with fresh water to wet the area of the ignition coils spark plug wires and spark plugs Do this in the shade or at dusk Any weakness in the insulation of connecting boots high tension coil cases or spark plug wires will immediately show up as sparks jumping from the poorly insulated wire or connection Any component that shows spark should be replaced Testing the Charge Coils For these tests you ll once more need to consult your engine s workshop manual Remember your charge and trigger coils are located under the engine fly wheel and you can t see them without removing it Removing the flywheel goes beyond routine testing and is not within the scope of this book You can however still test the charge and trigger coils for con tinuity and for a possible short to ground You can also test for voltage using the Mercury DVA tester and your multimeter The charge and trigger coils are just like your high tension coil They are made with a long tightly coiled wire insulated from ground Charge coils have higher resistance than trigger coils so they can generate higher voltage than do trigger coils This means the length of wire in a charge
408. shows some of this equipment Technology has been good to us electricians in the last several years and significant improvements in tools and equipment have been made specifically in the areas of multimeters and crimping tools we take a closer look at these in chapters 3 and 4 As you go through this book you ll see these tools in use with specific instructions for every test procedure you ll ever need on board your boat Electrical Basics You Need to Know Fig 1 9 Some basic and not so basic electrical tools from my collection Beginning at the lower left and moving clockwise are A wire stripper B cable cutter C ratcheting crimping tool D inexpensive Snap On induc tive ammeters E Fluke 36 high amperage inductive multimeter true RMS F miscellaneous jumper leads used for various tests G the Ancor Prova inductive ammeter with frequency scale H AC probe pen I AC LED socket outlet tester J Snap On ignition spark tester K 12 V test light probe Chapter 2 Working with Wiring Diagrams The Trouble with Boats In chapter 1 I mentioned that I first started work ing with electricity in the automotive trade and it wasn t until later that I became involved with boats One of the first things that I learned while working on cars was the value of a good wiring diagram With a glance at a sheet of paper covered with lines and squiggles and a plethora of other arcane hiero glyphics I could tell immediately
409. ssive amperage melts the element and opens the circuit but they offer several advantages over AGC fuses They are color coded for one thing and the colors match the amperage ratings as shown in the table in figure 4 9 on page 50 With AGC fuses you must remove the fuse to read the amperage however ATO fuses have the amperage embossed on the end of the fuse where it s always visible even when the fuse is installed ATO fuses have transparent plastic cases that allow you to see the entire element so there is never a question about whether it s burned out or not ATO fuses are also slightly easier to remove and replace than are AGC fuses A disadvantage to ATO fuses is that many of them use aluminum elements and blades Using these fuses flies in the face of the ABYC directive for not using aluminum wiring or connections on boats I have seen aluminum ATO fuses literally rot from corro sion when they were exposed to salt spray Always use 49 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS ATO in line blade fuse holders with rubber covers as shown in figure 4 10 If you find any aluminum fuses or fuse holders of any type on your boat you should immediately re ATO Fuses Color and Amperage Rating Dopo CIE ERS OG Nae NE Tan INE MEE ERE e Brown TES ur ba te ER ER NEED Red Teens etum cincti reir e eae Blue PE Pole tes 8 Dette ea Be A Yellow 3p Pon Here Shon ere pde gure qr Clear Trete Ete carer ence ear ane Green fore
410. sswork and old wives tales that had dominated the old school were no longer a part of my work I had found at last a guiding light to lead my electrical efforts through the dark jungle of naivet and ignorance The good news for boaters is that today more and more boatbuilders are building their craft to the ABYC standards and a genuine effort is being made industry wide to improve owners manuals and wiring diagrams so that they can be more easily un derstood by engineers and laypersons alike This trend toward universal standards of marine electri cal work has also had a profound effect on the ex pertise of all professional marine technicians from the person who designs the boat right down to the one who changes your oil and checks the gap in your spark plugs This includes you the boatowner Once you finish this book and develop a few of the ana lytical skills we will cover in the following pages your comfort level when working with things elec trical will be increased dramatically The Powerboater s Guide to Electrical Systems is not intended to turn you into an expert electrician It should however help you wade through the tech nical mumbo jumbo and electro speak that you re bound to encounter in your other reading on ma rine electricity Once you understand the basics much of the rest will follow in a clear concise and easy to understand manner All instructions and recommendations found in this guide are in accor d
411. st charging system in the world isn t going to fix it So the first step in checking out your charging sys tem is to test the battery as described in the last chap ter Ifthe battery is up to snuff you can test further to make sure your charging system is OK For any of the tests described here the batteries should not be fully charged because any charging system with a voltage regulator senses the battery charge and adjusts the charge rate to the charge needed Since a charged battery doesn t need any more charge the voltage regulator will tell the alter nator not to put out any current it s just not needed All these tests require current from the alternator and by discharging the battery a bit you ensure that there will be some To discharge the batteries disable the ignition system or diesel injection system and crank the en gine for 10 or 15 seconds several times Allow sev eral minutes between intervals for the starter to cool off so you don t damage the starter motor Never disconnect or reverse any battery cables or alternator leads with the engine running damage to the alternator diodes will occur instantly When the battery is disconnected the voltage regulator sees that the battery voltage has disappeared and tells the alternator to get to work The alternator responds with full output that can instantly shoot up to sev eral hundred amps and those internal diodes will 91 POWERBOATER S GUIDE TO ELECTRICAL
412. stant rate ferro resonant bat tery chargers which are found on all older boats and on new high production boats Sea Ray and Bayliner to name two have destroyed many gel cell batteries Gel cell batteries must be charged using a three stage smart charger covered in chapter 6 with the voltage set for gelled electrolyte Absorbed Glass Mat Batteries Absorbed glass mat batteries are also of the no maintenance type They have a sealed case just like their gel cell cousins you couldn t add water to these 87 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS batteries if you wanted to The primary difference be tween AGM batteries and gel cells is in the way the electrolyte is supported AGMs have a fiberglass mat between the cells that further supports the electrolyte There are other important differences though Tests have shown that AGMs are less sensitive to charge rates than gel cells perhaps making them a better choice if you own an older boat with a constant rate charger More on chargers in the next chapter No Maintenance Batteries Beware of batteries sold by some chain stores such as Sears and Wal Mart that purport to be no maintenance batteries and lack a filler cap just like gel cells and AGMs These are often wet cell auto mobile batteries that have an internal reservoir of electrolyte that s gradually used up as the battery is recharged Once this reservoir is gone the batteries are junk These might be fine for
413. starter motor current To test a solenoid first make sure that the igni e vA Fig 8 3a A heavy duty remote solenoid tion switch is delivering battery voltage to the sole noid and that the ground to the engine from the so lenoid is in good order You ll need your multimeter set on the DC volt scale to do all of the following tests except the ground continuity test Use your multimeter set to the ohms scale you used for testing continuity to make sure the ground from the relay to the engine is in good order Con nect one probe to the solenoid terminal with the black wire the red probe will be fine but it doesn t matter when checking continuity and connect the remaining probe to ground You should have a read ing of almost zero ohms and if your multimeter is equipped with a beeper for continuity it should beep If you don t find continuity clean the terminals at the relay and engine then recheck If the problem persists install a new ground wire Figure 8 4 on page 127 shows the ground being checked with a multimeter Once you have verified continuity to ground check the power lead on the solenoid for battery volt age The power lead will almost always be a large red wire but verify the color on your wiring diagram Fig 8 3b A light duty relay You might need a helper to turn the ignition switch while you check the meter Connect the meter as shown in figure 8 5 with the red probe attached to the r
414. state of charge Depending on the manufacturer one of the colors will indicate electrolyte loss This battery Fig 5 3 Battery carrying strap in use This type of strap as sembly will only work for smaller group 24 and 27 batteries Larger batteries all have carrying handles attached and should be handled by two people Cell opening with cap removed showing correct fill level Electrolyte u E LL Fig 5 4 Correct battery cell fill level Batteries and Battery Systems should not be charged but replaced Sealed batter ies should have a sticker on the top explaining the color codes p gt Keep batteries in a properly designed box secured to prevent battery movement in rough seas Make sure that all cable connections are tight and perma nent No alligator clips or twisted on connections are allowed gt Keep batteries clean and free from corrosion and any moisture or oily film on the battery top This is not only a safety consideration but also a great way to increase the life of your batteries gt Know which battery terminal is positive and which is negative This is important for the connect and disconnect procedures described above It will also prevent damage to polarity sensitive equipment like GPS and radar pm Battery terminals should be marked with a plus or minus sign or the positive terminal may be marked with red paint With a post type battery the positive terminal
415. t calm sea and not a cloud in the sky It s the perfect day for a family cruise the kind of day you bought your boat for You back the trailer down the ramp like an expert slide the old girl off the trailer with the panache of long practice lower the out drives and hit the blower switch to clear the engine compartment of any gasoline fumes prior to starting the engines Nothing happens Nada zip zero Without the blower you can t safely or legally start your engines No engines no Block Island No Block Island no pizza You aren t going to be a very popular guy and what has started out to be a perfect day on the water is rapidly deteriorating into a first class disaster What to do Lucky for you you bought this book and know exactly what to do The first thing you ll do of course is to check the state of the battery charge and all the terminals Once you have determined that everything is as it should be here move to the distribution panel and check the fuse or the circuit breaker for the bilge blower Now move to the switch on the panel identified hope fully as the blower switch and trace the two wires from there to the connection on the distribution panel Then trace the wires from the switch to the blower motor itself Aha Look there right where the blower leads emerge from the engine compartment bulkhead See that white powder on the terminal block It s copper oxide and it s a sure sign of corrosion Sure enough a
416. t came mae acces Orange Fig 4 9 ATO fuses color versus amperage rating Fig 4 10 In line blade fuse holder with rubber waterproof cap attached move them and replace them with tinned copper or brass fuses and holders If there is a question of what material an ATC fuse is made from simply scrape one of the fuse blades with your pocketknife Alu minum easily flakes away and reveals a shiny silver coloration right through the blade Tinned copper or brass will show a yellow or pink coloration as the tin coating gets scraped away Circuit Breakers Fuses are an inexpensive and effective way to protect most circuits from too much amperage and they are practically fool proof if you pay attention and match the fuse to the circuit you want to protect They do have several important disadvantages though For one thing once they blow they are useless and must be replaced This isn t an economic problem because both AGC and ATO fuses cost only a few cents apiece but it can be a nuisance if you blow a fuse and find that you don t have a replacement If this should happen with a critical piece of navigation equipment when you re caught offshore in a storm it could even be dangerous Another danger is that many of us faced with not having the correct size of replacement fuse will be tempted to use a fuse of a higher amper age or even worse to jump the holder with a piece of wire Actually a chewing gum wrapper is
417. t can be an expensive mistake Let s take a little time to review the selection process so you get just the right one for you Selecting a Multimeter Without a doubt the most important decision you ll make as you equip yourself for the electrical trou bleshooting procedures we will visit in the forth coming chapters is which multimeter to buy Even an inexpensive meter with limited capabilities will make working on your electrical system much easier than trying to do the job without one In fact many ofthe tests we will be discussing are impossible with out at least a basic multimeter However if you spend just a little more money and buy a meter with a few more advanced features you can expand your capabilities considerably allowing you to test for more things But it s just as easy to buy too much meter as it is to buy an inadequate one The current crop of multimeters range from under 20 to over several thousand dollars in price If you aren t care ful you can spend a lot of money on fancy features that you don t need and will never use Copyright 2000 2007 by Edwin R Sherman Click here for terms of use 26 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Digital versus Analog Meters The first decision you ll have to make is between a multimeter with a digital display and one with an analog display There are still inexpensive as well as expensive analog meters available for those few of us who still prefer them Ho
418. t do you do Often one or more of the various colors for wiring to the ABYC recommendations may not be readily available at the time you perform a repair and substitution may be the only practical solution It s perfectly OK to use one of the other colors pro vided you code both ends of the replacement wire with the proper color and then make a prominent note on the wiring diagram The best code medium in this case is colored heat shrink tubing but of course brown heat shrink is less likely to be available than brown wire In this case you could make do with a written label wrapped around the wire and pro tected with waterproof tape When you substitute wire colors circuit ID becomes doubly important Expanding the Basic Circuit Expanding the elements of the basic circuit to include the components shown in figure 2 6 you end up with something that looks very much as it might look if it were wired on your boat even though this might be hard to see in this compressed state In this dia gram I am illustrating what the wiring for a bilge blower circuit would look like if we backtracked to the master switch panel on the boat Figure 2 7 on page 20 illustrates what the power supply circuit to a master switch panel should look like with a circuit protector fuse or breaker and battery master switch installed I should point out however that many boats do not use a battery master switch and many installations don t have the fuse or
419. t lead and the black wire becomes the grounded lead This condition can destroy po larity sensitive equipment such as motors TVs and microwave ovens and it creates a serious shock hazard The bottom line here You need to be certain that wiring color coding is matched and appropriately con nected through every inch of the AC circuit from the shore power source all the way through your boat Testing for Polarity Many newer boats with AC distribution panels have a polarity test button right on the panel If you don t have one of these panels you can check polarity with your multimeter every time you plug in or you can buy a simple and cheap circuit tester see figure 11 9 on page 167 that plugs into any standard outlet If the indicator lights on the tester don t light up in the proper sequence you know you have reverse polarity somewhere in the circuit and you must shut down the circuit until you find it and fix it Figure 11 1 on page 160 illustrates typical AC wiring connections from the shore power inlet on your boat through the AC panel to a standard outlet Comparisons between AC and DC Circuits As with the DC circuits discussed throughout this book things like amperage and voltage are major 159 180 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Shore Power Cable Connector Shore Connection Shore Power Cable Power Inlet Electrically insulated from the boat if isolator is installed Mai
420. t the light socket reading from the source voltage reading and divide the result by the original source voltage Fig 3 6 Incorrect hookup of voltmeter across the switch of the same cabin light circuit When the meter is connected in this manner the source voltage cannot be measured The only reading you would get here is the voltage drop through the switch Let s assume you re checking voltage drop at the light fixture in the head First make sure that all DC circuits on board your boat except the one you re checking are turned off Battery voltage must be kept as stable as possible for this test and any circuits that are turned on will drain the battery if only slightly this slight drain can alter your readings Now check the voltage at your battery as described above If you re checking voltage at the distribution panel connect your meter with the red lead attached to the positive bus at the back of the panel and the black lead attached to the negative bus Record your read ing to at least two decimal places Fractions of a volt count here Next go to the light socket and check the voltage Again the red test lead probe should be attached to the positive side of the fixture and the black probe to the negative side You may have to disassemble the fixture to get access to the contacts for the light bulb Put the red probe on one contact and the black to the other and take a direct reading Make sure the Shift your decimal
421. t to render your rough sketches into a finished draw ing These stencils come in a myriad of styles and have hundreds of electrical symbols on them Either the stencil for basic DC systems or one designed for automotive applications will do just fine Once you have the stencil it s a simple though time consum ing matter of converting your crude sketches into a polished drawing with all the proper symbols Still another method which most true professionals are using today is to use a computer graphics program to acomplish the same task The only problem with this approach is that unless you re using a sophisticated program such as AutoCAD which has a substantial symbols library you ll find yourself having to create your own symbols These don t have to be compli cated however as long as they re properly labeled any unique shape will suffice If you want to carry the finished copy of your elec trical diagram to a ridiculous extreme you can take your roughs to an electrical engineering firm If you promise to leave a substantial portion of your mater ial wealth with them they will have your sketches rendered into a computer generated schematic that will be worthy of framing and hanging over your fire place They might even review your work and point out your mistakes Better yet if you happen to know a friendly electrical engineer or someone proficient with electronic drafting perhaps you can trade a weekend of chasing bluefish of
422. t when misap plied to a human body is unpleasant in the best of circumstances and in the worst it is lethal Extreme care must be taken any time your boat is plugged in to shore power has a generator running or has an operational inverter on board If after reading through chapter 11 of this book you still don t feel confident in your abilities to sensibly and safely per form the tests and procedures I have outlined you should stay away from the AC service on your boat I hope you enjoy the Powerboater s Guide to Electrical Systems and find it a useful addition to your arsenal of onboard tools As always good luck and happy boating xi This page intentionally left blank Chapter 1 Electrical Basics You Need to Know What Is Electricity One of the first things to confront a new student of electricity is the concept of just what the stuff is We all know that electricity travels through wires but when we inspect a cut cross section of one of these wires we see nothing more than copper and the idea of anything passing through it as water passes through a hose seems quite impossible The classic textbook definition of electricity translated from electro speak into plain English states that electric ity is the flow of electrons through a conductor from a negatively charged material into a positively charged material Nature abhors a vacuum and the positively charged material which has been stripped of electrons by one o
423. tence and the single most important element that makes it possible for the circuit to exist The load can be a light bulb or the depth sounder or the stereo system that con verts the electrical energy flowing through the cir cuit into something useful light information for safe navigation or pleasant and relaxing music The load also serves to control the unrestricted flow of electrons that would otherwise destroy the circuit and even burn up your boat in the process Remember this one simple fact whenever we have an electrical problem on board our boats we can always trace the problem to a fault with one or sometimes more of these basic elements Figure 1 1 shows the elements discussed above in a normal se quence as might be found on your own boat When the switch we show here is turned on referred to as closed in electro speak we can see the complete route that our friends the electrons have to follow If you follow the guidelines in this book like those elec trons follow that circuit you ll soon be tracing through all manner of circuits yourself and when you develop trouble spots you will in all cases be able to find them without difficulty Circuits Found on Your Boat In all of electrical engineering there are only two ba sic types of circuits common to boat use and your boat no matter how simple its electrical system might be will use both in abundance These are the parallel and series circuits Actu
424. ternator Disconnect the wire at both ends at the tachometer and at the back of the alternator and use your multimeter If you find con tinuity the problem is within the tachometer itself If you don t there is a break in the wire that should be located and repaired Voltmeter Checks In recent years console mounted voltmeters have re placed or on expensive instrument panels supple mented ammeters as indicators of battery condition and state of charge This change has taken place for economic reasons more than anything else Volt meters are less expensive than ammeters and they are much cheaper to install Ammeters require heavy wires or expensive shunts see chapter 3 whereas voltmeters for the largest batteries can be installed using 16 AWG wire Voltmeters impart slightly dif ferent information than ammeters but they are a very useful way of keeping an eye on your battery A digital voltmeter coupled with an electronic battery charger or smart charger is an excellent way of mon itoring the charge cycles discussed in chapter 6 If your voltmeter quits reading simply use your multimeter to verify that battery voltage is getting to the terminal at the back of the instrument and that the ground lead is properly attached and connected to ground If power feed to the gauge is OK and the ground is good there should be no questions here the gauge is bad and needs replacement A gauge reading higher than normal indicates a ch
425. th of these magnets To test voltage plug the red lead from the tester into the DC volt socket on your multimeter and Fig 7 18 DVA adapter 17 118 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS connect the black lead from the tester to the ground or negative socket Next plug the red and black probes from your meter into the corresponding sockets on the DVA tester and you re ready to take a voltage reading To test the charge coil set your voltmeter to a scale that will read about 400 volts Typical read ings at cranking speed for charge coils are between 150 and 275 volts You must check the workshop manual for your engine to get the exact specifica tions Plug the meter leads into the socket or con nect them to the leads coming from the charge coil Again your manual will help you identify these two wires Crank the engine or use the pull cord to turn it over while you take a reading from your meter You may need a second set of hands here Some of the newest meters have a peak reading button that will hold the reading until you can look at the me ter If your reading is within specifications the charge coil has tested OK and is not causing any ignition problems Testing the Trigger Coils Next test the trigger coil the same way you tested the charge coil only switch your multimeter to a voltage scale of 20 volts or less Typical trigger coil voltage readings will be between 1 2 and 9 volts at cranking s
426. than newer smart chargers To determine which type of battery charger you have you ll need to find the charger itself It will be mounted somewhere near the batteries If you don t see things like a battery type selector switch or a temperature compensation calibration switch some where on the charger you probably have the ferro resonant type and should seriously consider an up grade to a smart charger If you do have a ferro resonant charger on your boat make sure that none of your batteries are gel cells or AGMs You must be able to check your battery electrolyte level regularly if you have a constant rate charger The tendency particularly for people who plug into shore power and use their boats infre quently is to overcharge the batteries and boil out the electrolyte One trick used by many boatowners who have this type of charger is to leave on a DC powered cabin light or two even when they are away from the boat This light puts a small drain on the batteries minimizing the overcharging effect If you have a constant rate charger you should check all the cells in your batteries every two weeks or so and top them up with distilled water as needed Batteries that run low on electrolyte will burn up in short order Figure 6 12 shows a typical constant rate charger Smart Chargers The newest wave of electronic battery chargers generically called smart chargers is a by product of power supply technology for computers Sm
427. that reading light for example you ll find that those designed for campers will have a single wire usually referred to in electro speak as a lead and those designed for boats will have two Automobiles commonly use what are called chas sis ground circuits where the metal frame of the car the chassis or the engine block serves as the second wire of the circuit and provides a path for the electri cal current to flow back to the battery On a boat this simply doesn t work The fiberglass hull of the typi cal powerboat is a very poor conductor of electricity and on steel and aluminum boats an electrical current Electrical Basics You Need to Know boat stuff and car stuff and have resolved to never put car stuff in our boat let s get back to our three ba sic circuit types Series Circuits The simplest of circuit types is the series circuit widely used on your boat to supply electricity to single loads such as a cabin fan or bilge pump With this circuit type there is only one path for electrical current flow Figure 1 2 depicts a simple series circuit The inher ent problem with this circuit type is that it cannot be used effectively on board to service more than one electrical appliance Figure 1 3 on page 4 shows a se ries circuit with three cabin lights installed As you can see the electrical current must flow through one be fore it can get to the second then through the second before it can get to the third The p
428. that you can t buy a fuse or breaker that falls at exactly the 150 percent value The key words here are must not exceed I generally work in the range of fuses and breakers that are between 115 to 150 percent of the total amperage handling capabilities of the circuit I am trying to protect and can always find a match Distribution Panels Distribution panels and switchboards fall into a slightly different category than regular on board equipment The protection ratings for distribution panels that supply multiple branch circuits are designed to protect not only the panel but also the primary feed conductor to the board This may be an important consideration if your boat s original dis tribution panel has blank sockets where more equip ment could be added In general in order to save money and weight boatbuilders try to use the smallest wire sizes that they can get away with If your boat came through with let s say three blank holes in the distribution panel where additional circuit breakers or fuses could be installed you could have a problem The boat builder may have rated the wire going from the bat tery to the panel for the loads he installed without any consideration for reserve capacity As soon as you add anything to the panel you risk exceeding the capacity of the feed wire The ABYC recommendations for dealing with this situation are clear A trip free circuit breaker or a fuse shall be installed at the source of po
429. the frequency for normal range between 57 and 63 Hz in the United States gt If possible adjust the voltage regulator gt Verify correct engine rpm and governor adjust ments Erratic Voltage em The generator brushes could be worn or burned gt There could be internal wiring problems or loose connections Erratic Frequency em Check for loads cycling where the generator turns the current on and off Alternating Current and AC Equipment gt Ifthe frequency is erratic with all loads turned off check the governor for proper operation Can you hear subtle rpm changes High Frequency gt Have the governor operation checked Low Frequency gt Turn off all loads If frequency returns to normal the generator is being overworked and is probably underrated Either give up some AC toys or pre pare to upgrade to a bigger generator em Check for faulty governor adjustment Galvanic Isolators A device that has become increasingly popular in recent years on new boats is the galvanic iso lator The trouble with them is that most folks including many marine electricians haven t the faintest idea what they do So what are these things used for anyhow Well here s the defin ition A device installed in series with the green grounding conductor of the shore power cable which effectively blocks galvanic current flow DC but permits the passage of alternat ing current AC You re probably still wonde
430. the panel are not large enough change them to a larger size before doing anything else 7 Once wire gauge and circuit protection ratings are determined string the wire from the distribution panel to the location of your new cabin light Don t forget to support your new wiring at least every 18 inches and preferably more frequently than that If the wire must go through an area where chafe protection is needed provide it as shown in figure 4 20 on page 59 8 Connect the ground wire from your new light to the negative bus bar on the back of the distribu tion panel and the positive wire to the switch or circuit breaker output terminal You might need a two to one connector to tie into a breaker or fuse on the panel 9 At the fixture end of the wire use crimp type butt connectors to attach the new light to the feeder wires If the wire on light fixture pigtails is more than two AWG sizes apart use one of the new style step down butt connectors available through West Marine or any good electrical sup ply house 10 Finally flip on the switch Is there light If so your new circuit is a success Mount your new fix ture in position and enjoy Figure 9 1 provides a wiring diagram showing what your new light circuit might look like in a typi cal installation Individual switches are not illus trated at the light fixtures Installing a New Bilge Pump To install a new bilge pump first establish the gph gallons per hour
431. the trim mounting bracket assembly The tilt stop switch prevents the lower unit water pickup port from rais ing out of the water enough to cause inadequate water flow Figure 7 21 shows this switch on a 70 horsepower Mercury outboard To test the tilt stop switch remove the mount ing screw that secures it to the engine Disconnect the Fig 7 20 Typical wiring diagram for an outboard engine remote key installation remaining lead coming from the switch Now with your multimeter set to the low ohms R x 1 scale connect the meter probes to the two switch leads it really doesn t matter which probe goes where and position the switch in your hand as it would normally rest on the engine with the trim down The switch should be open and the meter should read no con tinuity or infinity Next tilt the switch in your hand and tap the high end of the switch with your finger The switch should close and the meter should now indicate continuity through the switch If your test readings are not as described here replace the switch Final Checks and Ignition Timing It is possible to thoroughly test all of the ignition parts have everything check out and still not have V c Fig 7 21 Mercury tilt switch This switch is designed to pre vent engine starting with the prop out of the water If it mal functions open circuits your engine won t start with the prop in the water either In this picture I ve removed the switch
432. tial electrical supply houses After a recent tour of several of these stores to see what multi meters were available I discovered that some of the meters they sell are designed just for home use They are just fine for work with AC current at home but they are limited in their DC measure ment capability a defect that renders them useless for onboard work A typical multimeter suitable for marine use will have a capacity of 600 to 1 000 amps in both the AC and DC modes and it will have resistance values up to 10 000 or 20 000 ohms or even more Root Mean Square RMS Multimeters Most of the desirable features of your new multime ter we will be discussing here apply to DC measure ments because that s where you ll be doing most of your work There is one important feature however that applies only to alternating current and that s in the way the multimeter reads AC voltage Less ex pensive meters called average responding multime ters read AC voltage by averaging the peaks of the wave form don t worry we discuss alternating cur rent thoroughly in chapter 11 which can give erro neous readings Root mean square RMS meters use a formula that compensates for the valleys and peaks of the wave form the root mean square of the maxi mum amplitude of the wave and gives a reading that s much closer to the actual usable voltage in the circuit Average responding meters will work just fine as long as you re measuring linear load
433. times it seems like powerboaters are the world s greatest gadgeteers We who own boats love the electronic devices that we install on or attach to them and from time to time as we can afford it one of our most pleasurable tasks is the selection purchase and installation of the latest piece of elec tronic gadgetry Few indeed are the boaters among us who fail to install some new electronic wonder on our boats at least once a year My current West Marine catalog is more than 1 inch thick and the lavishly illustrated pages are replete with images of all manner of electronic doohickeys all of which with very little imagination can become es sential to the safe and efficient operation of my boat There are no less than 26 pages of marine radios and accessories 10 pages devoted to GPS receivers 12 pages of electronic chart plotters and navigation soft ware 6 pages of radar and an entire section on light ing Of course you can view the entire catalog online these days at www westmarine com You can even buy a remote control underwater video camera with a 131 foot cable for a mere 5 999 Would I have one of these video cameras on my boat You bet I would and all that other stuff too Like nearly all boaters if it weren t for the con straints of a small budget and a lot of common sense I would need a bigger boat just to carry all the gad gets that I would like to install on it All this won derful stuff would help me navigate mo
434. to a known good ground take a reading on the positive side of the breaker the same way you did for a fuse If you get an identical read ing at the adjacent terminal on the breaker the breaker is working fine and any problems you may be having with the circuit have nothing to do with the circuit protection If you do not get an identical read ing on both sides of the breaker it s faulty and will require replacement Make sure to match the rating of the new breaker with the old one Figures 4 14a and 4 14b on page 54 show this test 93 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS 94 Figs 4 14a b Meter test sequence for a circuit breaker With one meter lead attached to a known good ground check the feed side of the breaker for 12 volts With the breaker turned on you should have 12 volts at the adjacent terminal on the breaker If not the breaker is faulty and must be replaced Levels of Circuit Protection Fuses and circuit breakers are intended to protect the wiring and components in the circuit from damage due to ex cess current flowing through any part of the circuit at any time The ABYC has come up with standards designed to provide the most practical solutions to the problem of protecting circuits However even the most experienced electricians and boatbuilders some times have trouble interpreting these standards The 100 150 Percent Rule The 100 150 percent rule contains the standards for
435. try banded together Organizations like the National Marine Manufacturers Association NMMA and the American Boat amp Yacht Council ABYC for contact information see the sidebar on page x were formed with the stated purpose of bringing order out of chaos by establishing a binding set of minimum standards for the construction of pleasure boats One of the remarkable results of the formation of organizations like these has been a steady decrease in the number of fatal boating accidents ABYC Standards and Recommendations The ABYC standards and recommendations to which I refer throughout this book do not just ap ply to boatbuilders however They apply to you and to me and to everyone who works on boats In fact recent certification programs for marine techni cians initiated by the ABYC drive home the point that the standards are as useful for repairing and modifying boats in the field as they are for building boats in the factories These standards are an in valuable tool for weekend boaters who decide to make their own repairs and perform some of their own installations Much of this chapter addresses the points you should consider when selecting wire Copyright 2000 2007 by Edwin R Sherman Click here for terms of use Wire and Circuit Protection Standards and Repair Procedures circuit breakers and fuses We will even discuss a few basic electrical repairs you can make on your boat If you own a boat that s more than a
436. ttery socket The female part of a plug and socket con nector solenoid An extra heavy duty relay Used for switching high current draw circuits such as starter motor circuits specific gravity The density of a fluid In electrical terms the density of battery electrolyte as com pared to pure water Indicates state of charge in a battery cell spike Sudden surge in voltage starting battery Cranking battery capable of deliv ering high amperage for brief periods static charge Surface charge on a battery High voltage but no amperage to back it up stator The stationary armature on an alternator that the rotor spins inside of where alternator current is produced stray current corrosion Corrosive activity induced by electrical leakage See corrosion sulfation The normal chemical transformation of battery plates when a battery discharges If left unattended the sulfate turns to a crystalline substance and attaches itself permanently to the battery plates ultimately ruining the battery as less and less plate area is exposed to the sur rounding electrolyte solution surface charge See static charge surge spike See spike switch A device used to open and close a circuit tachometer Revolution counter terminal A point of connection to any electri cal device As in battery clamp ring eye con nector etc tilt switch Mercury switch designed to turn off the starting circuit on an outboard engine when it
437. ttery let s see what happens to amperage when the resistance in a cir cuit changes from say 5 5 ohms to 7 8 ohms By di viding 13 5 volts by 5 5 ohms we see that the amperage draw through this circuit will be 2 6 amps By increasing the circuit resistance to 7 8 ohms we will end up with 1 73 amps If the resistance in a circuit is known or if it can be accurately measured we can apply this simple for mula as the first step in determining what size circuit breaker or fuse to use See chapter 4 for more detail on circuit protectors and how to select them As the resistance in a circuit goes up in value the amperage goes down Conversely as resistance goes down am perage goes up This trade off between amps and ohms is always valid regardless of the amperage and resistance as long as the voltage remains constant As for a practical application of the pie formula it s quite useful when you re adding AC appliances to your boat All Underwriters Laboratories UL ap proved appliances must have a tag or label affixed to them with the operating voltage and wattage of the appliance clearly stated By applying the pie formula and dividing the wattage by the voltage we can de termine how many amps the appliance will require for operation With DC appliances determining the amperage used by the load is always the first step in determining the size of the fuse or circuit breaker we will need and the size of the wire we will use to sup
438. tween amperage and voltage This means that an anchor winch using 80 amps with a 12 volt system only needs 40 amps to do the same amount of work with a 24 volt system On a 40 foot boat with a 70 foot wiring run from the battery to the winch and back to the battery this means the builder can use a 1 0 AWG cable instead of a 2 0 AWG cable Using West Marine 2006 prices the builder saves nearly 125 just in the cost of the cable plus all the components are smaller and lighter and easier to install When you buy a new piece of equipment to in stall on your boat the manufacturer will always pro vide the voltage required to operate the equipment It will be printed in the installation instructions or on the equipment itself and sometimes in both places Before you begin installing your new gadget double check to make sure you have one with the right voltage All the following assumes you re work ing on a boat with a 12 volt system Amperage Requirements The next important specification is the expected am perage the appliance needs to operate efficiently Again the packaging should provide this important information and will often recommend the fuse or circuit breaker rating as well Sometimes the rated voltage amperage or wattage is also embossed on the equipment but not always Wherever you get the numbers a consideration of the amperage and voltage should always be the first step in selecting the appropriate wire gauge to use on
439. ty starter motor The house battery is used to run equipment such as cabin lights stereos re frigerators and electronic equipment that isn t con nected to the engine The starting battery should be Batteries and Battery Systems a heavy duty marine cranking battery and the house battery should be a deep cycle marine battery One of my boats a 15 foot dory I use for bay fishing has a single deep cycle battery that I use to operate my fish finder and running lights at night The engine is a pull start outboard so I don t need a cranking battery If I had an electric start engine on this boat I would consider an additional cranking battery even for a boat this small I hate paddling it just takes too long against a 2 knot tide My other powerboat a 25 foot V8 powered walk around is set up with a group 27 cranking bat tery and a group 27 deep cycle marine battery Deep Cycle versus Cranking Batteries The difference between cranking and deep cycle bat teries is simple Cranking batteries are designed to provide a burst of cranking power for a short period of time Once the engine is running the engine s al ternator will kick in and quickly recharge the bat tery replacing the power used to start the engine Cranking batteries are not designed to be discharged deeply over and over again You would be lucky to get one season of boating out of a cranking battery used as a deep cycle house battery Deep cycle batteries on
440. ty until the voltage reaches somewhere between 15 5 and 16 2 volts This controlled overcharge literally rattles the sulfate particles out of the battery plate forcing them back into the electrolyte where they belong The danger with using the equalization phase is that you can do it too often In some industrial ap plications equalization is used as a part of every charge cycle because maximum battery punch is required This is simply not the case on a powerboat and you should equalize your batteries no more than three or four times per boating season Not all smart chargers offer an equalization phase On those that do it s not automatic and must be selected manually Temperature Compensation All of the smart chargers I have worked with have some form of temperature compensation built in to help the brain of the charger determine the proper charge rates Three common arrangements are avail able One method requires the installer to select a temperature setting from a selector switch mounted on the charger housing Another uses automatic temperature compensation with a built in tempera ture sensor on the charger I feel that these two meth ods although certainly offering a technological quantum leap from the ferro resonant chargers are still a bit lacking The best sensing for temperature compensation can only be made at the battery itself The temperature of the battery will change dramati cally as it charges whereas t
441. u want to mea sure the amperage hook the probes up in series and hope that the amperage doesn t exceed the ca pacity of the meter If it does there will likely be some fireworks either a blown fuse or a blown me ter With the inductive meter simply clamp the crab claw around a wire making sure the wire is centered and oriented properly if you get it back wards you get a negative reading and read the am perage off the scale no hassles disconnecting wires and no fireworks A few of the better more expensive meters such as those made by Fluke have an optional clamp that plugs right into your existing meter converting it to the inductive pickup type These are fine meters but the adapters often cost more than the meter it self By the time you add up your total investment you would be better off buying a separate meter with a built in clamp Keep it simple to read big amps get a meter designed to handle the task right out of the box In summary for most basic circuit checks on your boat a meter with a 10 to 20 amp capability will do the job However if you wish to check alter nator output in amps starter current and anchor windlass loads you ll need the higher amperage capabilities of some of the better meters There are many multimeters available and the one you select will depend on your budget your boat s equipment and the intensity of your desire to do it all The Multiple Multimeter Solution Ihave
442. uc tive pickup over the main battery cable going to the starter motor and take a reading while a helper cranks the engine Now you have the normal amper age you can expect your starter motor to draw If you don t have an inductive pickup multimeter one of the inexpensive Snap On inductive meters shown in my tool collection in chapter 1 will do the job When you have a starting problem that you think might be caused by the starter motor first double check your battery to make sure it s charged and in good condition then repeat the current draw test If your new reading is lower than the previously estab lished benchmark reading the starting problem is probably due to loose or corroded terminals in the bat tery cable connected to the starter motor If the cable has been replaced since you established your bench mark and the terminals are clean and tight the new cable is probably undersized and needs to be upgraded If the reading you get is higher than the bench mark reading make sure that the problem is not caused by a mechanical fault such as a partially seized engine or a frozen drive unit You may need to call in a pro to help out at this point Once you re cer tain that the engine is not causing the problem you can be sure that any excess current drawn by the starter motor is due to a fault within the motor Re move it and send it out for overhaul Voltage Drop Test Another useful test for your starter motor and starter ci
443. ugh the isolator Remember that the green wire is designed to pro tect against shock and its integrity is of paramount importance Since the isolator is mounted in series with the green wire as the first stop past the shore power connector on your boat and is often not easily accessible the isolator s integrity must be known at all times A blown diode inside the isolator could have the same effect as clipping off the third grounding ter minal on an extension cord as men tioned earlier In consideration of all this the current version of ABYC Standard A 28 Galvanic Isolators mandates a status monitoring device for a gal vanic isolator Both Guest and ProMariner make such devices which consist of a remote panel that alarms if a failure occurs These mon itors also seem to do a very good job of identifying other electrical prob lems often with the dock wiring the boat is plugged into This has been such a problem that an ABYC com mittee is now considering a new type Fig 11 23 A ProMariner galvanic isolator of isolator that is rated as electrically fail safe meaning that if a diode fails electrical continuity through the device cannot be compromised As of this writing the committee has not finalized a new draft of the standard for re view Rest assured that boating magazines will pub licize the final decision If you re uncertain whether your boat even has a galvanic isolator check with y
444. uit Fig 4 22 The rule for soldering battery cable ends Wire and Circuit Protection Standards and Repair Procedures Unapproved wire connector Approved wire connectors LLL Fig 4 23 Preferred types of connectors and types that are not allowed When selecting terminals refer to the color codes and match the terminal color to the appropriate wire gauge The colors are as follows Red 18 16 gauge Blue 16 14 gauge Yellow 12 10 gauge Burgundy 8 gauge Never crimp a wire into a larger terminal that s not the correct size Either the connection will not hold or you ll lose some of the strands in the wire creating an increase in resistance Crimping tools have changed over the last few years Today s ratcheting crimping tools do a fine job and take away the big question did I squeeze the pliers hard enough These crimpers are easy to use all you do is squeeze the handles until the ratchet snaps and you can be sure the connection has been squeezed hard enough One disadvantage to these new crimpers is that manufacturers have designed them to use only their own terminals Thus you can only be certain of the integrity of the crimp if you use terminals designed to match the crimper This is not a huge problem if you buy your supplies at the same place you bought the crimper but be aware that the crimper you buy may not be compatible with all brands of terminals Fig ure
445. ump master switch panel 142 Connecting the Pump to Power There are several points to consider as you determine where you want to connect your new bilge pump to a power supply If you connect it to the main distribu tion panel the pump will be off when the master switch is thrown This might be fine for a boat ona trailer but less so for one kept at the dock or ona mooring where the pump needs to be on while every thing else is off Often pumps are connected directly to the battery and fed through a dedicated switch panel described above but loading up a series of connections directly to the battery is simply not good practice The ABYC suggests that no more than four conductors be attached to any one termi nal If your battery has a stud type battery post you ll be limited by that restriction Also locating fuses near the battery is a mistake due to the poten tial accumulation of corrosive vapors near the bat teries The resulting corrosion of the fuse and fuse holder can cause excessive voltage drop and all the problems associated with it I m not suggesting that you not attach your new pump directly to the battery it is often the best op tion but if you do use the ABYC standard to your advantage You can mount the fuse as far as 72 inches away from the battery as long as the wiring is sheathed in addition to its insulation and still be in compliance with the standard Another option is to use a single appropriately
446. und on standard engine installations Figure 4 21 on page 60 shows a variety of acceptable wire securing devices Connecting the Dots Making Wiring and Connection Repairs In making repairs to existing wiring or building a new circuit for the latest electrical appliance you ve purchased proper techniques and components can make all the difference in the world when it comes to preventing problems later Take the time to do the job right and do it once Soldering Terminals Over the years there has been some controversy and discussion among electricians regarding soldering versus crimp type connectors used in electrical wiring on boats For years I labored over each con POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS Fig 4 21 Tie wraps and other acceptable clamps for securing wiring harnesses nection carefully soldering each lead I considered crimp on terminals to be the easy way out and infe rior to soldered terminals Well times have changed and so has my view of the proper way to attach ter minals to the ends of wires In fact I no longer use solder for any of my connections Crimp technology has improved significantly so that if the crimps are applied correctly you won t have any problems with them at all Premier boatbuilders are using crimp connections exclusively with no problems and I m now convinced that crimping connectors is more practical than soldering them It s certainly a lot more tim
447. units are sealed and use two wires to connect the sender to the inside of the boat The wires are fed through the drive unit s gimbaled bracket assembly disappear ing behind the engine where they are ex tremely difficult to get at Besides the difficulty of getting to the wires the hole where the wires pass through the transom must be properly sealed to prevent seawater from leaking into the boat Unless you re an experienced technician I do not recommend attempting to replace these senders on your own This is a good job for a professional with experience not only in the replacement of trim gauge sending units but their proper adjustment as well tronic shop gauges necessary to verify exactly what s going on with your engine Once proper operation has been verified in this manner record the normal read ings of your gauges Remember while underway you re looking for readings outside these pre estab lished norms If you follow the steps outlined in this chapter you ll have the confidence and ability to tackle and repair most instrument failures that crop up on your boat Remember that as with all the other sections of this book you should never attempt to go too far with your diagnosis and repair without the aid of your workshop manual Also remember that the basic electrical trou bleshooting and repair procedures already discussed will carry you through any diagnosis of instrument problems The Future Figures 10 10a
448. ur problem goes past checking the fuse spark plugs and wires coils and looking for corroded or loose connections all of which I described earlier in this chapter To sum this section up remember these impor tant facts Most problems with ignition systems will be visible a broken wire a corroded connection or bad spark plugs that should have been replaced Also because of the variety of engines and ignition systems you must use this book together with the service manual for your engine If you follow the guidelines and the simplified test procedures in this chapter you ll be able to pinpoint and repair the most common and some not so common ignition system problems If your tests lead you to a difficulty that must be handled by the dealer you ll have saved the labor dollars you would have spent for the tests Chapter 8 Tracing and Repairing Starter Motor Circuits Here is an all too familiar scenario You wake be fore dawn get the old Donzi hooked to the back of the station wagon and are at the launch ramp a good hour before the weekend rush Half an hour later she is in the water tied to the dock loaded with your entire family a few friends a picnic lunch beer soda pop fishing gear water skis two gallons of SPF 30 sunblock and the family rottweiler The rising sun is shining the birds are singing the sea is flat calm In short it s the start of a glorious day a perfect day to spend on the water Finally
449. use on a motor cir cuit could be an especially bad move It could literally cause a meltdown of the motor as well as a lot of un necessary correspondence between you and your in surance company Installing Your Own DC Accessories Now that you have determined the gauge of wire and the size of the fuse you ll need for your new bilge pump circuit remember that the insulation of the wire should be moisture fuel and oil resistant in case a spill or leak ends up in the bilge Not that you d pump the spill out with the bilge pump of course but the reason for this precaution is so that while you re removing the oil by other means you won t damage the wiring to the pump Next remember that any wire terminals exposed to bilge water require a waterproof connection A good choice for joining wires in the bilge or in other wet areas is the new crimp type connectors that have a sealing heat shrink jacket as shown in figure 9 3 Securing the Wires To remain in compliance with the ABYC standards secure the newly installed bilge pump wires at a min imum of 18 inch intervals The truth is that this stan dard is quite lenient and most quality builders secure their wiring at 4 to 6 inch intervals Good choices for securing your wiring are the p clips or screw footed tie wraps available at any ma rine supply house Look through the selection at a good electrical supply retailer and you ll find a mul titude of ingenious options for
450. using while the engine is not running To do the survey make a list of all the electrical equipment you have on your boat List everything from the fish finder to the light in the refrigerator Now refer to the average power ratings found in fig ure 3 15 on page 37 and honestly estimate your av erage daily use of each item on your list Multiply the amp hours by the number of hours or fraction of hours for each item to get the amp hours used each day by each piece of equipment Next add up the amp hour per day figures and the total will give you a pretty good idea of your total daily amp hour consumption Now double your daily amp hour figure remembering that you don t want to discharge the batteries to below a 50 percent charge and you have an accurate amperage rating for your house battery Purchase your batteries accordingly and remember when it comes to deep cycle batteries cold cranking amps is an irrelevant number You need to be concerned only with the amp hour capacity sometimes known as the 20 hour rating The 20 Hour Rating The 20 hour rating of a battery specifies the amount of amperage it can supply for 20 hours at 80 F 27 7 C Figure 5 2 shows the correlation between typical battery size by group number amp hour rating and cold cranking amps Never assume amper age capacity based on size or group cate gory of a battery Always check the actual battery specifications with the seller You Batt
451. ver In the case of a manual start motor the pull cord simply won t budge more than several inches as you pull with all your might If either of these deadly symptoms is present you have an internal engine problem that goes beyond the scope of this book For a solution to these and most other outboard engine problems I strongly recommend my book Outboard Engines Maintenance Troubleshooting and Repair This concludes the starter motor section of this book By following the tips and guidelines here you should be able to trace your way through just about any starter motor and starter circuit problems you encounter and keep your boat on the water instead of in the shop 135 Chapter 9 Installing Your Own DC Accessories Installing your own electrical equipment is not only a rewarding personal accomplishment it can also save you a lot of hard earned money If you bought a new boat it may have come with a long list of op tional extras probably a VHF radio and a fish finder and maybe a chart plotter and radar If you bought a used boat the previous owner undoubt edly added an assortment of electronic and electrical gadgetry to the list However no matter how well equipped your new or used boat may be you ll eventually want to make some modifications to the electrical system Sooner or later you ll want to add a new light fixture an upgraded battery charger a better VHF radio or an extra bilge pump By fol lowing my r
452. ving in my head for years Of all the different areas I work in diesel and out board engine mechanics and onboard systems elec tricity is one of the most interesting as well as one of the most perplexing to many people Even boating professionals who have worked in and around wa tercraft all their lives sometimes find the funda gt ABYC To find out more about the ABYC contact them at 613 Third Street Suite 10 Annapolis Mary land 21403 Phone 410 990 4460 Fax 410 990 4466 www abyc com mental princi ples of electricity difficult to un derstand Elec tricity is often seen as a myste rious force that except when it shows itself in a spark or in the fluc tuation of the needle or dancing digits of a multi meter is invisible in a controlled state The effects of electricity however can be quite profound as any one who has inadvertently bridged the terminals of a freshly charged battery or latched onto the wrong wires in a hot AC circuit can attest I was fortunate in that I recognized the arcane and slightly magical qualities of electricity early in my ca reer and this gave me a distinct advantage over my colleagues As a teacher and practitioner of the elec trical arts as well as a mechanic I was forced into a deeper comprehension of the underlying principles of electricity In order to teach others the fundamen tals of electricity I had to translate the technical mumbo jumbo that obscure
453. w about Benjamin Franklin who in 1752 proved that lightning was electrical when he flew a kite during a thunderstorm He tied a metal key onto the string and as he suspected it would electricity from the storm clouds flowed down the string which was wet and he received an electrical shock Maybe not the smartest of ideas but it sure brought the point home fast Throughout the next hundred years many in ventors and scientists tried to find a way to use elec trical power to make light In 1879 Thomas Edison was finally able to produce a reliable long lasting electric light bulb in his laboratory From that point forward the world would witness profound tech nological advances By the end of the 1880s small electrical stations based on Edison s designs were springing up in a number of U S cities But each station was able to power only a few city blocks Elementary electrical systems were beginning to find their way onto ships and onto pleasure craft reserved for the affluent few During those early days electrical safety standards were virtually nonexistent both on land and at sea Although the majority of people living in larger towns and cities had electricity by 1930 only 10 per cent of Americans who lived on farms and in rural areas had electric power But that was about to change rapidly through the 1940s and 1950s as America was thrust onto the world stage fighting a second world war the Korean conflict and the Cold
454. water heater element or an electric coffee maker The Ed Sherman Wiggle Test When checking the conductor continuity in any flex ible cord such as a shore power cord it s a good idea to perform what I call the wiggle test Alternating Current and AC Equipment ime Fig 11 13 An inductive current clamp used to check current on an AC appliance These cords take quite a beating and are fre quently abused It s quite possible to get a solid con tinuity reading with your meter and lose continuity when the cord is flexed especially close to the ends where the cord s three conductors attach to the plug ends Figure 11 14 on page 170 shows a typical shore power cord being wiggle tested To do the Sherman wiggle set your meter to the ohms scale and connect one meter probe to the prong on the plug and the other probe to the corre sponding socket at the other end of the cable You should get a very low ohms reading near zero if all is well Next bend and flex i e wiggle the plug and socket ends while firmly holding the cable Carefully observe your meter and look for a change from alow ohms reading to an open circuit reading of infinity or OL on digital meters A fluctuating reading indicates a break in conti nuity behind the insulation at the plug end Check all three conductors in this way to be sure they re all OK If any momentary break in continuity is indicated a suitable replacement end will need to be i
455. wer for panel boards and switchboards and shall not exceed 100 percent of the load capacity of that panel or 100 per cent of the current carrying capacity of the feeders There is an exception to this rule that will apply to many newer boats the fuse or circuit breaker for the wire that connects the battery to the distribution panel may be rated at up to 150 percent of the capacity ofthe wire if the panel is equipped with a submain circuit breaker rated at no more than 100 percent of the load on the panel Figures 4 15 and 4 16 on page 56 show these possibilities and the allowable ratings Acceptahle Locations for Fuses and Circuit Breakers The next consideration you ll need to make if you re adding electrical equipment to your boat is where to locate the fuse or circuit breaker Not all fuses and breakers are mounted on the main distribution panel so some rules for placement of these devices are needed POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS MAIN AND BRANCH CIRCUIT PROTECTION Main Circuit Switch Protection Feeder 9 Breaker Main Breaker Branch 9 Breaker e Battery l Sub main s Main o Breaker o Breaker A 21 oe Main RS 9 Breaker l l Branch d Breaker Panelboard bm mm Fig 4 15 With this installation submain breaker installed the main circuit protector can be rated up to 150 percent of the feeder wire ampacity ABYC Feeders
456. west engines where resistor type wiring is used in which case some resistance will be indicated on your meter Next hold the probes in place and bend and flex the wire while carefully observing the me ter If the reading fluctuates there is a break in the wire inside the insulation Replace the wire When reinstalling ignition wires make sure to use the hold downs found on many engines These hold downs keep the wire from coming in contact with moving engine parts that may chafe the wire and ultimately cause it to fail Apply a light coating of waterproof grease to the ribbed ceramic insulator and metal connector of the spark plug and coil con nector before reinstalling the spark plug wire The grease will help the boot to seal out moisture that would eventually corrode the metal connector on the end of the wire Testing High Tension Coils In the repair shop a technician normally uses one of the testers specially designed to work with CDI systems These testers are quite expensive and should not be a part of your tool collection even though not having one will limit your ability to do advanced ignition system tests You can however do many tests with your spark tester your multi meter and a spray bottle filled with fresh water These simple tests will enable you to narrow down possible causes of an ignition fault and in most cases 115 116 POWERBOATER S GUIDE TO ELECTRICAL SYSTEMS find the culprit behind it At
457. wever for general marine work a good digital meter is so far superior to the analog models that the latter aren t really worth con sidering regardless of any cost considerations The trouble with the inexpensive versions of the analog meters is that they often have no internal cir cuit protection making it easy to destroy the meter if you connect it improperly Further many of these meters suffer from low impedance or internal resis tance which reduces the sensitivity of the meter Me ter sensitivity is an important consideration for many of the procedures outlined in this book Even with an expensive analog meter that s con nected correctly it s easy for a novice to make a mis take in measurement because the analog dial is difficult to read These meters have adjustable scales that can be confusing to use and require the user to interpolate values if the needle falls between two lines on the scale Incorrect readings that are easy to make with an analog meter are all but impossible to make with a digital meter even for a beginner There is a huge selection of digital multimeters available The simple to follow specifications listed here will help you to narrow down the field to exactly what you need Digital Features You Need You must make sure that the multimeter you se lect has all the features you need for boat work Be particularly wary of some meters sold at the major home supply stores such as Home Depot and residen
458. wheel induce an electric current as they rotate past specially designed coils located very close to the mag nets One of the coils under the flywheel is called a charge coil As the flywheel magnets spin by this coil sends a fairly high alternating current voltage to the ignition control module which is sometimes called the power pack or CDI unit This will be around 200 volts AC depending upon which system you have As already mentioned the other ignition coils found under the flywheel are called sensor OMC pulsar Yamaha or trigger coils Mercury I will call them trigger coils here to avoid confusion The trig ger coils send electrical signals to the CDI unit to tell it which cylinder to work with at the correct time Next you ll find the CDI unit itself This device is the brain of the system and serves several functions First it converts the alternating current from the charge coil into usable direct current Next it stores this current in the built in capacitor mentioned ear lier The CDI unit also adjusts timing by changing the interval at which the trigger coil sends a signal to the module The timing changes with any change in en gine rpm and is adjusted by a change in the relative position of the trigger coil to the flywheel magnets A timing plate to which both the charge and trig ger coils are mounted controls this adjustment Me chanical linkage connected directly to the engine throttle linkage constantly adjusts t
459. will wear out the bearings that support the pulleys such as those on the alternator and water pump Adjust the belt to the correct tension as determined by measuring the de flection of the belt then retighten the bolts Recheck the belt tension after about 10 hours of engine oper ation as the belt will have a tendency to wear and loosen This is normal but must be attended to Newer boats are now coming through with serpen tine belts figure 6 5 familiar to the automotive world for several years now and these promise to last much longer than the conventional V belt In addi tion all of the systems using these belts have a self ad justing mechanism built into the pulley system With these belt drive systems it is extremely im portant that all the belt driven pulleys are in perfect fore and aft alignment Any spacer shims used to ad just the fore and aft position such as an alternator mount pivot bolt must be reinstalled after any com ponent in the system is removed and replaced Mis aligned pulleys will cause the belt to walk off them once the engine is running Fig 6 5 Serpentine belt Fig 6 6 Engine mounted circuit breaker Engine Mounted Circuit Breakers While you re at it check all the circuit breakers lo cated on your engine Each of these will have a little red button with a number like 10 25 30 40 50 etc stamped on the end Figure 6 6 shows a typical circuit breaker installation One or more
460. wiring in circuits conductor Any material that has a minimal amount of resistance to electrical flow through it conduit A pipe in which electrical wiring is routed continuity A complete path or circuit that will al low electrical current flow continuous rating Rated for continuous exposure as compared to intermittent exposure corrosion The process by which metals are de stroyed See also galvanic corrosion stray current corrosion crimp n A type of connector used for terminat ing wire As in captive ring eye etc v To attach a crimp type connector to a wire using an appro priate crimping tool cross induction The inducement of electron flow in a conductor from the magnetic field surround ing a nearby current carrying conductor CRT Cathode ray tube Televisions and comput ers before they went to flat screens used to have CRTs current The movement of electrons through a ma terial cycles In AC the current shift from to and back to is one cycle DC ground conductor A normally current carrying conductor connected to the side of the power source that is intentionally maintained at boat ground potential DC grounding conductor A normally non current carrying conductor used to connect metallic non current carrying parts of direct current devices to the engine negative terminal or a bus attached directly to it Its purpose is to help minimize what is known as stray current cor rosion
461. x e wh ft sss S m S Fig 4 3 The ABYC s Table X from section E 11 showing conductor sizes for a 3 percent drop in voltage O ABYC 44 Wire and Circuit Protection Standards and Repair Procedures CONDUCTORS SIZED FOR 10 VOLTAGE DROP NOTE In the event of a conflict between the voltage drop table and the ampacity table use the larger wire size Length of Conductor from Source of Current to Device and Back to Source Feet 10 15 201 125 30 40 50 60 70 80 90 100 110 120 130 140 150 160 TOTAL CURRENT ON 12 Volts 10 Drop Wire Sizes gauge Based on Minimum CM Area CIRCUIT IN AMPS Nn nN m eo o o e 5 10 15 20 eo OA SH NMNLADO gt OO NNA LADD O NNASDAODs OANNNAOODS OOANNAAADDA m e m X e mM TO RORBGROOO PO IO PO IO 4 O OD CO PPNA OOOO OA NNNADOM OO NNAADOD DOOOHAHNNNFAFADOAOO NOOA HNMNAHAOO m A e e e mm RR oo 24 Volts 10 Drop Wire Sizes gauge Based on Minimum CM Area 18 18 18 18 18 18 18 16 16 16 18 18 18 18 18 16 16 14 12 12 18 18 18 16 16 14 14 12 10 10 18 18 16 16 14 14 12 10 10 10 18 16 16 14 14 12 12 10 8 8 18 16 14 14 12 10 8 16 14 14 12 12 10 16 14 12 12 10 8 14 12 12 10 10 14 12 10 10 8 14 12 10 10 8 12 10 10 8 8 12 10 10 8 8 fo i 40 0 0 NNSA DM NNNNPADHO NNA HAD 32 Volts 10 Drop Wire Sizes gauge Based on Minimum CM Area 18 18 18 18 18 18 18 18 18 16 18
462. xposure to exhaust manifold heat These wires must be kept secure in the factory supplied hold down straps found on all engines Fail ure to do so will almost always result in problems like engine misfiring and skipping System Cleanliness Probably the biggest cause of ignition system failure on any engine is the accumulation of dirt and oil film Contrary to popular belief spraying down the coil plug wires and distributor cap with products like CRC 6 56 or WD 40 to seal them from moisture is in fact one of the worst things you can do The oily film they leave behind is a magnet for dust and dirt which attract moisture and condensation Moisture is a good conductor of electricity and any weak points in the insulation on the secondary side of your ignition system will provide a natural path to ground or between cylinder towers on dis tributor caps Both situations are classic examples of the short to ground or intercircuit shorts described in chapter 1 These shorts not only cause skips sputters and misfiring but they are unsafe Remember We want ignition protection at all times on gasoline powered boats and any stray sparks from the high tension side of your ignition system clearly preclude that Keep all of your ignition parts clean and free from any oily buildup at all times If necessary use one of the many products readily available for engine degreasing Ignition System Trouhleshooting Problems with your boat s
463. y provided by a differential receiver An antenna mounted too high will drive the GPS unit crazy as it swings back and forth trying to find its exact location Low and as close to the centerline of the boat as you can get is the way to go with this installation Any of the com mercially available mounting brackets for these an tennas will do just fine but don t think you ll improve performance by using an extension pole as you might with a VHF antenna If you have a differential GPS receiver DGPS one that also receives radio position data from land based stations in addition to satellite signals you may need an additional positive and negative wire to the antenna As with fish finder and depth sounder transducer cables your GPS antenna comes with a fixed length cable for attachment to the display unit Don t alter Installing Marine Electronic Equipment its length and keep any extra cabling coiled away from other cables and harnesses Figure 12 13 on page 190 illustrates a typical wiring hookup for a GPS without DGPS Figure 12 14 on page 190 illustrates a typical installation with a DGPS receiver Installing Your Own Radar In the old days the average boatowner wouldn t have dreamed of installing his or her own radar Today radar manufacturers have come a long way and owner installation is not only practical but not that difficult The big consideration with radar is the mount ing of the antenna scanner Four basic rule
464. ydrometer 83 84 battery installation acceptable possibilities for 73 74 INDEX battery cables 77 battery combiners 77 82 battery isolators 77 79 82 battery switches 77 79 81 series and parallel connec tions 76 77 battery isolators 77 79 82 battery life 68 battery location 73 74 battery safety 72 74 battery switches 19 20 77 79 81 belt tension and replacement 89 90 bilge blower amperage draw 43 circuit for 19 20 21 wiring diagram 21 bilge pump installation 140 44 141 142 143 wiring diagram 143 bimetallic circuit breakers 51 blade type fuses ATO 48 49 50 blinking out of electronic gear 82 blocking diodes 99 Blue Sea Systems 82 bridge rectifiers 86 87 bulkheads abrasion protection through 58 59 bulk phase 97 98 bullet type connectors 145 bus type fuses AGC 48 49 butt connectors 63 64 cabin lights circuit diagram 32 installation 139 40 wiring diagram 140 cable coaxial 184 86 cables battery 77 131 cables vs wires 77 calories 6 capacitive discharge ignition CDI systems 104 105 110 12 capacitive discharge ignition CDI unit 100 101 104 110 111 112 118 121 122 134 carbon tracking 107 8 cathode 65 156 CD players installing 144 46 wiring diagram 146 Centerpin PL 259 CP coaxial connectors 186 charge coils 104 111 115 116 18 117 charge controller 99 charging amperage test 93 chassis ground circuits 3 cir
465. you re ready to go You run the bilge blowers for a while then with a captain like flour ish you turn the ignition switch and nothing hap pens Suddenly everyone is staring at you and the rottweiler is making rumbling noises deep in his throat In desperation you try the switch again still nothing Then you check the battery switch the bat teries and all the terminals They are all OK but the rottweiler s lip is starting to curl and your passengers are picking up blunt objects as they form a circle around you What are you going to do Well it s a good thing you bought this book Sooner or later it s bound to happen You turn your ignition key to start the engine and it wel comes you with a disheartening click click sound or perhaps no sound at all These classic symptoms could well indicate a starter motor or starter circuit problem Let s take a look at these symptoms try to understand what they mean and then look at a few ways to fix the problem before the rottweiler makes an early brunch of your leg Like all problems with electrical circuits dis cussed in this book you need to systematically at tack difficulties with your starter motor and not skip any steps in your diagnosis Mistakes here can be ex pensive not only in the cost of replacement parts but in time spent getting to the starter motor Boat builders have an uncanny knack for burying these 123 important parts in obscure places where you ll swear you ne
466. your boat to literally dissolve in seawater A com mon cause of stray current corrosion is wiring that uses a boat s electrical bonding system as the DC ground for various appliances typically bilge pumps Any live wire hanging in the bilge water could be the culprit The only direct path for stray current to flow be yond any individual boat is via the green grounding conductor in the AC shore power system that is ex cept for a leak into the water surrounding the boat It s important to note that the galvanic isolator is de signed to isolate only low level galvanic DC current Its purpose is to block only about 1 4 volts or less not a full 12 volts All precautions must be taken to en sure this green wire never has high level current try ing to find ground through it unless an AC system fault occurs The isolator is intended to block only the natural galvanic current that will try to pass due to the electrically connected dissimilar underwater metals discussed The isolator uses four heavy duty diodes often combined with a capacitor to absorb any voltage surges that may occur These diodes use their inher ent resistance and one way capability to effectively block any small amounts of DC flow Galvanic cur rent is measured at less than 1 200 millivolts or 1 2 volts If a fault in the boat s AC system develops and the green conductor must be put into real service AC can easily overcome this resistance and will flow thro
467. your car but they have no more business on your boat than any other automobile battery A few may even be marketed as marine batteries so be extra careful when buying from discount stores The best policy is to buy your batteries from a reputable supplier who specializes in batteries for boats Battery Life But what about charging cycles How many times on average can the different types of batteries be dis charged and recharged before they need to be re placed This is a difficult question because the number of charging cycles that you can expect out of a battery depends upon the rate and depth of dis charge the recharging method and the quality of the battery construction Also batteries of the same nominal size will often have different amp hour ca pacities and the real concern is cost per amp hour The Typical Battery Charging Cycles table above represents the average number of times top quality batteries of each type can be discharged and recharged Cheap substitutes will provide a much lower average number of cycles Cost Comparisons Conventional wet cell batteries are the least expen sive of the three types we have discussed no matter Typical Battery Charging Cycles Decal Mex seek oe ys 800 2 000 cycles 1 400 avg AGM Ak serene 1 000 5 000 cycles 3 000 avg Note The above averages are based on manufacturer s claims under ideal conditions Actual averages will be considerably lower in the less tha
468. your distribution panel to a new depth sounder but the leads built into the sounder are only 16 AWG the fuse must be rated for the 16 AWG leads even if they are only a few inches long Wire and Circuit Protection Standards and Repair Procedures Bus Fuse ATO Fuse Type ey Fig 4 8 Bus type glass fuse slow blow cylindrical fuse ATO blade type fuse AGC and MDL Fuses AGC fuses often generically called bus fuses are the popular 1 25 inch glass barrel fuses with tinned cop per end caps that have been around since the begin ning of time They are by far the most common type of fuse used to protect individual pieces of equip ment and circuits on boats today and are the type most often supplied with a piece of equipment when you buy it Many bilge pumps just to name one item will have an AGC fuse in an in line fuse holder wired right into the positive lead of the pump At least one manufacturer PAR voids the warranty on the pump if this fuse is tampered with As you examine an AGC fuse you may notice that it has a voltage rating embossed on the metal end cap Usually this will be a fairly high number like 250 volts Since you re using these fuses for DC cir cuits this rating is completely irrelevant and can be disregarded If you blow a 10 volt fuse for example it s perfectly OK to replace it with a 250 volt fuse or vice versa However you would never replace a 10 amp fuse with anything other than
469. z Some of the better multimeters on the market have the ability to measure fre quency and this is not a bad feature to from the generator manufacturer If in doubt make sure you have the service manual at hand and use it Figure 11 22 shows the frequency being verified on a typical marine generator Generator Safety Over the years marine AC generators have evolved into quite sophisticated pieces of equipment and as a result the safety features available today are extensive Built in sensors shut down the generator in the event of such things as low oil pressure engine or exhaust system overheating and even excessive exhaust back pressure on some models The problem is different manufacturers use different systems and features will vary even from one model to another from the same manufacturer To familiarize yourself with your gen erator get out the owner s manual and if you intend to do any but the most basic service or troubleshoot ing on the unit get the workshop manual as well Most inadvertent generator shutdown problems are due to loose connections low oil pressure is there oil in the engine or an overheating engine You may have to trace through the cooling system troubleshooting section of your workshop manual to find the solution and get the generator up and run ning again have if your boat has a generator installed or you re thinking of having one added Measuring Generator Output Verifying gene

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