Ok, I am out for the definative anwser to my battery issues. I am going bigger on my stereo set up and feel a 3rd battery is in order. I have standard "house" and starting batteries on a 1-both-2-off switch. I would like to add the 3rd battery to the house bank- where all amps draw power. Do I need an isolator in there? I recall someone mentioning a relay in one of the threads . . . I am itching to go play with the boat, so any thoughts (happy) appreciated!!!1

Weasel,

I have a good used battery isolator out of my 382 if you need one. Two input, three outlet. Let me know if you want it for a reasonable price, like 1/2 off new ($175).

RD

I put an isolator / combiner setup in my last boat. Nice functionality. Isolates the banks when motors are off, automatically combines when + voltage either from shorepower or altenators detected. Got it from West Marine, though there is website (forget where) that you can get factory 2nds recon'd cheap direct from the company who makes them for West Marine.

Does require a bit of rewiring. Basically you need 3 on / off switches. One for each bank on/off, and one to combine the circuits if needed in an emergency. Make one bank "starting only", the other for everything else / house. Sort of a PITA, but when it's done, your boat is "idiot proof", no more reaching under the seat to switch from all to 1 or 2 - done automatically.

I haven't done it to my 311, but it would be nice have again. Haven't seen the latest West Marine catalog, but they used to have a nice write up on how exactly this works.

Weasel,

I have the box and diagrams that came with the new isolator. I also have a hand-drawn diagram from Technical Assistance at Formula. I do not have a scanner or computer at home, but I can fax them to you if you provide a number (or I can mail copies to you).

Isolator is from my '99 382. I thought it was causing my electrical problems last summer, but new replacement did not fix them so it is a spare.

It secures to the side wall in front of the battery bank inside the engine compartment. One lead from each alternater feeding in, two or three leads feeding out to batteries.

Let me know if you want the diagrams.

RD

I will pm you- thanks