Two battery switches

[Bobkat]

Can someone explain why Bertram installed two battery switches in my B31? I am using two batteries for two engines and it seems one switch would do.

If someone has the answer, can you also describe the proper wiring hook up. Are there any schematics on the web?

[In Memory Walter K]

I would assume to be able to have a house battery that can be called upon in an emergency for either engine.

[Charlie J]

i have 5 switches that i can back feed from either batterys or isolate

[luis]

I always find usefull to have 2 switches cause when runing I have one switch on 1 and the other on 2 , this means that I have 1 engine charging 1 group and the other engine the other group or in your case , each engine can charge his own battery. And you also can choose from wich group you want to crank each of the engines. Anyway, I believe that always used 2 switches for 2 engines. My 2 cents (of €uro).
All the best

[PeterPalmieri]

I recently found out on my boat.....

I have 2 batteries and 2 battery switches each says 1,2, both or off. From the factory they are wired basically on and off, one battery dedicated to each motor and will not charge off the other motor. Parallel switch on the bridge allows me to start either engine off both batteries.

If one battery dies I can use the parallel to get it's engine started and then the motor will recharge the battery. Other boats may differ but mine is not ideal.

I plan on having the wiring redone and will also add a house battery.

[Bruce]

You want each engine running on its own battery, not both engines running on one battery or two paralled.

It also may be wired to be able to parallel them together should on one battery go dead.

Bertram did not wire in a 3rd battery for house, which should be done.

They combined the house and stb engine together.

[Bob H.]

Bobkat, I went three switches one battery per engine two for house, black box with yellow tabs in the bottom right is combiner, one engine charges both house and starting battery, when you hit the starter it "separates" so you dont spike electronics. Only combines when needed, no voltage drop like isolation relay. BH

[Marlin]

I have 3 2150 gam batts , 3batt switches and a VSR, voltage sensing relay, that is wired off the strb batt switch, that so far has kept the house batt charged, only made one trip, 7 hours to Key West with 3 Simrad displays, 6 kw radar, black boxes, auto pilot pump/system, stereo, air-conditioning pump and engine electronics drawing off the house batt with no issues, I monitor the activity with a digital voltage/ amp gauge on the FB , can see the VSR kick in and out with voltage changes, I have also tied in a 3bank batt charger that will also support the batts when the generator is running , which is constant , as I need to cool the FB as I have a non venting EZ2CY enclosure , I can set the switch locations to parallel everything should I need it

[Charlie J]

nice neet wiring job bob