Dual battery, dual motor wiring

[shauncooper]

Hi all - looking for some tips and suggestions on the best wiring setup for a dual outboard and dual battery setup.

 

[ocnslr]

You don't indicate which boat you have, or engines, so don't know if this will work for you.

1. Two (2) starting batteries. Each one wired through the usual Off-1-Both-2 battery switch. Starboard engine connected to terminal "1" on both switches and port engine to terminal "2" on both switches. Either or both batteries can be used to start an engine, but the NORMAL line up is with one switch in position 1 and the other in position 2. Each engine starts on one battery and charges that battery.

2. One (1) or (preferably) two (2) batteries in parallel as the "house bank". This bank is connected to an "On-Off" battery selector switch. The Auxiliary Charging Lead from both engines is connected to the battery terminal on the switch, so either - or both - engines charge this bank.

3. If you have a 3-bank charger, as we do, then you can connect to each of the starting batteries and the house bank.

We repowered from a single to twins in Oct 2005 and I set up this arrangement. I just replaced all four batteries this summer - only because it seemed prudent, not because they were exhibiting problems. We are in the water all year, and use the boat all year.

I can send you photos if needed.

Brian

 

[Curmudgeon]

Wire and switch so each battery (however many) can start either engine, and can also be paralleled to start either. There are numerous ways ... :wink:

 

[max366]

I tried to post the wiring diagram from my Grady but attachments can't be done. The diagram is excellent- shows how a charger can be added, the bilge pumps, and you can start either engine with either battery. I suggest going to the Grady customer resources site, pull up a manual for boat with dual engines and the diagram will be in the back of it. I have a 2004 265 Express and I know that diagram is great. Good luck

 

[shauncooper]

Thanks for the suggestions so far guys.

OCNSLR, I have an '87 Offshore Pro 240 and twin Evinrude 150's (2-strokes). I would certainly appreciate if you could post some pictures of your setup. I have some ideas in mind from some research on the internet, but these involve only two batteries whereas the 4 that you suggest with a house bank seems to make much more sense.

 

[shauncooper]

I'm pretty sure, or at least I havent noticed, an auxillary charging lead from my motors, so not too sure the 4 battery setup will work?

 

[ocnslr]

I'm pretty sure, or at least I haven't noticed, an auxilary charging lead from my motors, so not too sure the 4 battery setup will work?

If you don't have auxiliary charging leads, then you would have to use other electrical devices to charge a separate house bank.

You are probably better off with the usual Grady two-battery set-up, with one as the house bank. Just have to be careful not to run it down too far, or you will have to start that engine from the other engine battery.

 

[Steds83]

OCNSLR - which 3-bank charger did you choose? Have you been happy with it? Thanks.

 

[ocnslr]

OCNSLR - which 3-bank charger did you choose? Have you been happy with it? Thanks.

It's the Charles charger that was installed at the factory. 20-amp, three-bank.