After many hours studying 12 volt electrical systems and batteries for boats, I finally decided to put my thoughts down on paper (actually AutoCAD). I don't even come close to being an expert electrician (I'm a land surveyor), but after reading all the specs and wiring diagrams I have seen on various vendor web pages (Ample Power most informative), I am posting a digital drawing of what I intend to install in the next few months. I would like any input, comments, suggestions that might improve my design, and most of all, if there are any safety concerns, please feel free to tell me if I'm gonna burn my boat down to the waterline. Brent Headberg West Palm Beach, FL S/V Elena Lua - 1990 Hunter 335
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Brent, Nice drawing. I'm not positive, because my installation guide on the link is on the boat, but I think you have the shunt turned around in the drawing. I believe the double lug side should go towards the ground (I really can't remember, so check this). Also, you show no fusing at the positive lead of the house battery and near the batteries on each charger positive lead. Consider fusing or circuit breaker for the alternator lead also. We did this on our 356. I do not have any experience with the solar, but I think 50 watts is probably ok unregulated. Dan Jonas (S/V Feije II)
Brent, Nice drawing. I'm not positive, because my installation guide on the link is on the boat, but I think you have the shunt turned around in the drawing. I believe the double lug side should go towards the ground (I really can't remember, so check this). Also, you show no fusing at the positive lead of the house battery and near the batteries on each charger positive lead. Consider fusing or circuit breaker for the alternator lead also. We did this on our 356. I do not have any experience with the solar, but I think 50 watts is probably ok unregulated. Dan Jonas (S/V Feije II)
Shore Charger?
Does your system have a shore power charger? Where is it schematically? What will it be?(Maybe it's on the drawing and I just can't read the writing.) I am also planning an upgrad that involves a battery combiner, but will probably choose the Heart because it has the emergency parallel switch built in for just $20 more. If you didn't have the link interface, the shunts wouldn't be necessary, correct? I might have put the solar panel on the other side of the "on-off" switch, just so you could really, really take house the battery out of the circuit. I'm sure you mulled that one over, too. I really wish that our website rendered your drawing a little better.
Does your system have a shore power charger? Where is it schematically? What will it be?(Maybe it's on the drawing and I just can't read the writing.) I am also planning an upgrad that involves a battery combiner, but will probably choose the Heart because it has the emergency parallel switch built in for just $20 more. If you didn't have the link interface, the shunts wouldn't be necessary, correct? I might have put the solar panel on the other side of the "on-off" switch, just so you could really, really take house the battery out of the circuit. I'm sure you mulled that one over, too. I really wish that our website rendered your drawing a little better.
another question...
How did you decide which side of the combiner to put the house/starter batteries on? In the setup you have, the house batteries are directly wired to the alternator. The starter battery is connected to the alternator through the combiner. Does it even matter? Paul
How did you decide which side of the combiner to put the house/starter batteries on? In the setup you have, the house batteries are directly wired to the alternator. The starter battery is connected to the alternator through the combiner. Does it even matter? Paul
Combiner
Paul, I would not refer to the Blue Seas battery switch as a combiner, although it can physically combine (parallel) the batteries in question, or simply select between the house and starter battery for starting. To me this is just a battery switch (although a nice one with dc panel breaker built in). The secret to the proper hook-up is apparent when you look at the leg that runs through the dc circuit breaker for the dc panel, regardless of battery switch settings. I would reserve the term combiner for the equipment that would physically connect the batteries automatically determinate on an adequate charging source. The author has not tried to include a combiner system. Hooked the way he has it, he will have no alternator charging to the starter battery unless he throws the battery selector switch to physically parallel the battery banks. I do not think this is necessarily a good idea, unless he remembers to keep that switch engaged when the engine is running. That switch is labeled (I believe), on this Blue Seas switch as "emergency cross connect", not exactly intuitive for charging the starter battery. I think it is important to always have the starter battery immediately recharged by the alternator. Hooking the alternator lead to the starter battery, or simply using the starter wire as the return for the alternator charging would accomlish this. However, hooked this way, you would not have alternator charging to the house bank, without throwing the cross connect switch. It is great to utilize the available power to replenish the house bank after the starter battery is recharged. A combiner in the system could automate that process. Regarding the earlier question regarding shore power. The charger is located at the lower center of the drawing. The ac power side was omitted from the drawing, I assume, because the author was concentrating on the charging dc circuity. He does show the two positive charging leads going to each battery and a dc ground to the ground bus. With a combiner this section of the circuitry would also change. Hope that helps a little. Dan Jonas (S/V Feije II)
Paul, I would not refer to the Blue Seas battery switch as a combiner, although it can physically combine (parallel) the batteries in question, or simply select between the house and starter battery for starting. To me this is just a battery switch (although a nice one with dc panel breaker built in). The secret to the proper hook-up is apparent when you look at the leg that runs through the dc circuit breaker for the dc panel, regardless of battery switch settings. I would reserve the term combiner for the equipment that would physically connect the batteries automatically determinate on an adequate charging source. The author has not tried to include a combiner system. Hooked the way he has it, he will have no alternator charging to the starter battery unless he throws the battery selector switch to physically parallel the battery banks. I do not think this is necessarily a good idea, unless he remembers to keep that switch engaged when the engine is running. That switch is labeled (I believe), on this Blue Seas switch as "emergency cross connect", not exactly intuitive for charging the starter battery. I think it is important to always have the starter battery immediately recharged by the alternator. Hooking the alternator lead to the starter battery, or simply using the starter wire as the return for the alternator charging would accomlish this. However, hooked this way, you would not have alternator charging to the house bank, without throwing the cross connect switch. It is great to utilize the available power to replenish the house bank after the starter battery is recharged. A combiner in the system could automate that process. Regarding the earlier question regarding shore power. The charger is located at the lower center of the drawing. The ac power side was omitted from the drawing, I assume, because the author was concentrating on the charging dc circuity. He does show the two positive charging leads going to each battery and a dc ground to the ground bus. With a combiner this section of the circuitry would also change. Hope that helps a little. Dan Jonas (S/V Feije II)
Tough drawing to read 
Dan, isn't the label on that thing in the lower center "West Marine 30A Battery Combiner?" Maybe it says "Batter Charger." I can't read it and I even enlarged the drawing. Unfortunately, size isn't the problem it's resolution. I think that a combiner is a must-have in this system, where there's a clear attempt to isolate the house bank and the starter bank on the discharge side. I think I would want my starter battery direct-connected to the alternator, even with a combiner. It may not make much difference if the combiner works as advertised, but it would make me feel better. He may not have shore power, however (hence the solar). Maybe he's on a mooring. My IDEAL system would be to have a dual-output alternator, eliminate the combiner, and complete isolate the two battery systems except for an emergency parallel switch.
Dan, isn't the label on that thing in the lower center "West Marine 30A Battery Combiner?" Maybe it says "Batter Charger." I can't read it and I even enlarged the drawing. Unfortunately, size isn't the problem it's resolution. I think that a combiner is a must-have in this system, where there's a clear attempt to isolate the house bank and the starter bank on the discharge side. I think I would want my starter battery direct-connected to the alternator, even with a combiner. It may not make much difference if the combiner works as advertised, but it would make me feel better. He may not have shore power, however (hence the solar). Maybe he's on a mooring. My IDEAL system would be to have a dual-output alternator, eliminate the combiner, and complete isolate the two battery systems except for an emergency parallel switch.
Re: Combiner
I really appreciate everyone's input, and I must apologize for the quality of the drawing. It's hard to get a quality image with the restrictions of 80KB per image on this web site. If anyone is interested, please feel free to email me and I will send it to you in pdf format. To answer some of the questions about my diagram: There is a West Marine 50amp Battery Combiner to connect the two banks together when the charging source is available. I don't have a 110v battery charger on my boat because my boat lives on a mooring 365 days a year. I rely on solar charging. Thanks again for your input. Brent Headberg S/V Elena Lua brenthg@yahoo.com
I really appreciate everyone's input, and I must apologize for the quality of the drawing. It's hard to get a quality image with the restrictions of 80KB per image on this web site. If anyone is interested, please feel free to email me and I will send it to you in pdf format. To answer some of the questions about my diagram: There is a West Marine 50amp Battery Combiner to connect the two banks together when the charging source is available. I don't have a 110v battery charger on my boat because my boat lives on a mooring 365 days a year. I rely on solar charging. Thanks again for your input. Brent Headberg S/V Elena Lua brenthg@yahoo.com
last comment, and thanks
Brent, I have studied your drawing a lot, since I am planning a similar project this offseason. Since I park at a slip, my setup will have a shore power inverter/charger, too. The only comments I have about your design are: 1. The blue sea battery switch is a cool thing, compact and neat, but it doesn't give you $160 worth of function. Is it really important to add a circuit breaker to a wire that's headed for the circuit breaker panel? For $60-$90 you could buy three simple on/off switches that would give you the same thing. 2. I'm going to wire my alternator to the starter bank side of the battery combiner. Since I am looking at a 50-amp shore power charger, I will probably get the larger (100A) Heart combiner. Maybe that's overkill, but I am reluctant to run a component at its top rated amperage. For the solar charger you have, the little combiner is perfect. Yours is a good drawing, based on some good research. Thank you for posting it. Paul sv Escape Artist h336
Brent, I have studied your drawing a lot, since I am planning a similar project this offseason. Since I park at a slip, my setup will have a shore power inverter/charger, too. The only comments I have about your design are: 1. The blue sea battery switch is a cool thing, compact and neat, but it doesn't give you $160 worth of function. Is it really important to add a circuit breaker to a wire that's headed for the circuit breaker panel? For $60-$90 you could buy three simple on/off switches that would give you the same thing. 2. I'm going to wire my alternator to the starter bank side of the battery combiner. Since I am looking at a 50-amp shore power charger, I will probably get the larger (100A) Heart combiner. Maybe that's overkill, but I am reluctant to run a component at its top rated amperage. For the solar charger you have, the little combiner is perfect. Yours is a good drawing, based on some good research. Thank you for posting it. Paul sv Escape Artist h336
12 Volt Wiring Diagram
I am going to take the advise of those that suggested I hook my alternator (+) wire and hook it to my starting battery. That seems more logical anyway. My House Bank will be continually charged by solar panel and West Combiner will kick in to trickle starting battery too. Thanks for the help. I plan on starting this project in a couple of weeks. Should be cooling down here in South Florida by then...(yeah maybe 82° instead of 90°). It sure will be hot down there under the aft berth. Cap'n Brent S/V Elena Lua
I am going to take the advise of those that suggested I hook my alternator (+) wire and hook it to my starting battery. That seems more logical anyway. My House Bank will be continually charged by solar panel and West Combiner will kick in to trickle starting battery too. Thanks for the help. I plan on starting this project in a couple of weeks. Should be cooling down here in South Florida by then...(yeah maybe 82° instead of 90°). It sure will be hot down there under the aft berth. Cap'n Brent S/V Elena Lua
Clarifications
Brent and Paul, Thanks for the clarifications. I did think that the combiner in the drawing was the charger. And I held the computer screen right up close so I could try to read it. You can do what Paul suggested with a few cheaper battery switches, but I like the Blue Seas set-up. Also, some dc panels do not have a seperate disconnect, so having it at the battery switch helps, and besides, the breaker protects the wire from the switch to the panel. Drawings like these help a lot in understanding the operation of the charging system. Also go a long way towards trouble shooting. I need to draw mine out again...lost it sometime back in a hard drive failure. Dan Jonas (S/V Feije II)
Brent and Paul, Thanks for the clarifications. I did think that the combiner in the drawing was the charger. And I held the computer screen right up close so I could try to read it. You can do what Paul suggested with a few cheaper battery switches, but I like the Blue Seas set-up. Also, some dc panels do not have a seperate disconnect, so having it at the battery switch helps, and besides, the breaker protects the wire from the switch to the panel. Drawings like these help a lot in understanding the operation of the charging system. Also go a long way towards trouble shooting. I need to draw mine out again...lost it sometime back in a hard drive failure. Dan Jonas (S/V Feije II)
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