SeaWeasel

ALL RIGHT. '89 311 sr-1. Dual batteries, dual alternators, single switch (1-2-both-off), shorepower battery charger. I need to add a 3rd battery to the "house" side. Can it be done? If so, how? All the diagrams I have seen like this are 2 switch set-ups. I assume I need an isolator- where the hell does it go? This is driving me nuts and my stereo install will not be complete until I get this figured out. I e-mailed Formula- and God bless 'em -they got right back with a schematic and told me to see my local marine mechanic about it. While "my" mechanic is the cat's pajamas with everything else- stereos, batteries and the like are not his bag.

Poorsche

I hope a real techie gest this straight -- I've got an SR357 and formula set it up the same way. Both batteries go to bus posts and then to a single switch. Looks like a major re-wire to get to true dual system.