Battery isolation (non chevelle)

MO_chevelle · Mar 16, 2004

I am working on a boat and want too add a second battery too it that will be charged with the normal charging system along with the original battery but when I use it I do not want this battery to be able too drain the other battery. The add on battery is for a radio and occasionally a trolling motor. I was told there was some sort of kit too buy too do this but it is expensive(i think) so I was wanting too know if any of you have any ideas on how too do this. Maybe using a diode?

John_Muha · Mar 16, 2004

There's really only a couple of ways to do it safely without using matched batteries. Even with matched batteries, one will die faster than the other.
The cheaper way is to use a large contactor but don't believe it's the best way. Diodes are the way to go for isolation but not the little ones. Think I linked into this site before. They seem to make a decent diode isolator.
http://www.hellroaring.com/

d1_bradley · Mar 16, 2004

These are available at NAPA and Pep Boys, etc. http://www.surepower.com/Products/batiso.asp

Old Longboarder · Mar 17, 2004

Go to a Recreation Vehicle store and get a dual battery solenoid.
Tie the two batteries together with cables to the two large posts of the solenoid. Run a 10 gauge wire from the ignition switch to the small post on the solenoid. When the key is turned on, the solenoid activates, connecting the two batteries so they'll charge. With the key off, solenoid is deactivated and batteries are seperate.
The solenoid will look like an old Ford starter solenoid, but it is designed to be activated for prolonged periods of time. A Ford type solenoid will work, but won't last very long.
This solenoid is very cheap compared to the battery charging isolators and does exactly what you're looking for.

MO_chevelle · Mar 17, 2004

Sounds like a winner Longboarder. Thats exactly what I was wanting too here, thanks alot.

Battery isolation (non chevelle)

MO_chevelle

John_Muha

d1_bradley

Old Longboarder

MO_chevelle

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