Dual Engine - Dual Battery - Wiring

Electrical and electronic topics for small boats
lonestar
Posts: 2
Joined: Fri Feb 16, 2018 2:27 pm

Dual Engine - Dual Battery - Wiring

Postby lonestar » Fri Feb 16, 2018 3:11 pm

I'm new to this forum and I know that this topic has been covered before, specifically the paper by JWHebert on dual battery wiring. I have wired my boat's batteries by switching between two batteries and two engines using the ground line rather than switching the positive lines. People seem to think this wouldn't work.

Are there sneak circuits here that may cause problems?

I run the engines in the "both" position and store the boat in the off position. For a weak battery start I jumper across the two "positive" poles and then remove it after both engines are running.

Would I be better off with one of Hebert's Boston Whaler wiring diagrams?

Or, am I essentially doing the same thing here?

Thanks
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jimh
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Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
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Re: Dual Engine - Dual Battery - Wiring

Postby jimh » Fri Feb 16, 2018 5:50 pm

I am most certain that no one would recommend or endorse your method of interrupting the battery negative circuit to the engines. The principal harms in leaving the engines connected to the battery positive are:

--risk of accelerating galvanic corrosion of the engine's metal chassis that is exposed to the sea

--risk of some unanticipated ground return circuit in accessory wiring being in place and taking the load current of the engine.

I don't see any particular notion of an advantage to be achieved in interrupting power distribution in the ground return side of the circuit. This is universally avoided.

lonestar
Posts: 2
Joined: Fri Feb 16, 2018 2:27 pm

Re: Dual Engine - Dual Battery - Wiring

Postby lonestar » Fri Feb 16, 2018 7:28 pm

Thanks for your input
I'll take your advice