typical setup for twin engines and 3 batteries?

[TitanTn]

My new to me 300 Weekender has twin 350s, 3 batteries and one 1,2,ALL,OFF Perko switch. What is the most likely scenario for how this is wired? One battery for each engine and one for the house? So what's the point of the switch? Battery 1 is actually two starting batteries and battery 2 is the house? Some other scenario?

Thanks.

 

[julietbravomike]

You can download your owners manual from Sea Ray's website and it would have the details. I would guess you have 2 deep cycles hooked together that are either on the 1 or 2 position and then a starting battery on the other position. Your alternators may run through an isolator then to each bank for charging. If I'm right, then the switch would just be used if you ran down your house batteries - switch to the starting battery and away you go.

 

[TitanTn]

Thanks for the reply. I cannot find my manual on the Sea Ray site for a Weekender.

I used it this weekend for the first time off the shore power. The switch has been in the ALL position and I know one of the 3 batteries is new. Both engines turn over quickly and don't seem to lack for power during starting. I turned the switch to 1 when we anchored and the battery only ran one light in the cabin for about 30 minutes before it started dimming. It went down very quickly after that.