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lenm
01-07-2006, 08:39 PM
Could someone explain the best way to setup batteries for a twin outboard setup - ie. battery switches/charge relays required.
Also can 2 motors be run off a single battery should one of the 2 batteries die? or is a third battery normally utilised as backup for the other 2.

Thanks
LM

Spaniard_King
01-07-2006, 08:48 PM
Run each engine on it's own battery but connect the earth terminals of each battery together using a suitably sized battery lead.

Then all you need to do is connect each positive battery post to a battery isolation switch. If one battery is flat make the isolation switch and start the engine with the flat battery. It's a good idea to firstly start the engine with the good battery before making the isolation switch.

Don't worry about the engine charging systems they will take care of themselves. The only other thing is to never leave the isolation switch made for long periods or you could flatten a battery as both engines will charge the good battery.

hope this helps..

Garry

boatboy50
02-07-2006, 08:33 PM
Hey Garry,

I have twins now and they both run off seperate batteries, but can be started off one as you describe.

During the week I had one flat battery, so started both off the good battery.

I then switched them from the one good battery to both on the switch to charge the dud battery.

I have been told that switching to both while the engines are running can spike or destroy the motors electronics or computer. Is this true? I've always felt guilty for doing it thinking I could destory the electronics, but had to out of necessity. Is it another wives tale?

Regards

Darren

Spaniard_King
02-07-2006, 09:28 PM
Hi Darren,

bit of a myth that one, I change mine all the time when the engine is running.

I dont like to run with both batteries beeing charged from the same source. can hurt one of the batteries ..long term

cheers

Garry

lenm
04-07-2006, 06:31 PM
Thanks Garry - that setup sounds nice and simple.
LM