Quote Originally Posted by lo-lyf View Post
I would use a cirquit breaker or marine battery selector switch before using a fuse in this application. Relays are automatic though, no popping the hood to turn a switch, or trip a breaker, etc. Great idea none-the-less for a cheap way to keep one isolated.
yeah i like the idea of a relay the best really. easy, cheap and a simple switch in the dash can control it. there are so many ways to go about it, you could have it setup where it's one battery, the other battery, or both. for the life of the batteries it's best to run them dual all the time and have matched batteries.

the peak voltage should be as close as possible to each other. i got 2 red top optimas that are still working after 12 years now.