Weird multiple battery set-up?

[philtheskipper]

Just found out that my boat has two batteries hooked up with a switch. The switch can run both, or each one individually. What puzzles me is one is a typical (cranking) battery and the other is a deep cycle. I'm a bit confused cuz I was told both should be the same type. Is this an ok set-up? If it is, when should each battery be used/on? Should I have both on while the engine is running so they charge? When the engine is not in use should I run electronics off the deep cycle only or can I leave both on at all times?

 

[petryshyn]

Re: Weird multiple battery set-up?

Its going to depend on how you use them. <br />If you deep discharge the deep cycle by using trollers, lights and appliances for long periods, likely you will need to recharge the deep cycle with a land charger. The reason for this is because you will not likely run the engine long enough to sufficiently recharge it. If this is the case, leave it selected to the cranking battery all the time, and replenish the deep cycle on shore.<br />If you don't deep discharge, and only use the appliances and/or lights for short periods, then select "both" when starting and running. Don't switch over while running. Make your selection before cranking.... <br />Also, when the boat is not being used, do not leave them connected together as in "both". Select "off" for safety and longevity of both batteries

 

[philtheskipper]

Re: Weird multiple battery set-up?

Thanks for the tips!

 

[Boatin Bob]

Re: Weird multiple battery set-up?

Agree with Schematic....no idea what kind of a boat you have but if you have an automatic float switch on your bilge pump make sure it is wired up so that if you turn both batteries off the pump still has power otherwise you may have an unpleasant surprise one day. The reason he has you turn them off is because no matter if they are the same or not but if one were to go bad it will pull the other one down with it because they will always try to equalize with the switch on both.

 

[philtheskipper]

Re: Weird multiple battery set-up?

Never thought about the bilge pump! I should be ok since I currently trailer the boat. If I ever do dock it I'll rewire the pump.

 

[CJSundancer]

Re: Weird multiple battery set-up?

Okay, here is one... I have 4 batteries... but the batteries is not what i question but where the battery selector goes... Somebody ripped the wires out and now i need to re-wire the batteries. Unfortuneatly i don't know where the selector goes and need to find that before i purchase the battery cable. I have a 26ft 1983 SeaRay Sundancer with a mercruiser 260... I believe it was originally 3 batteries, but previous owner had to many electronics.

 

[Bob's Garage]

Re: Weird multiple battery set-up?

I don't know the model boat, but generic advise should work.

Install the switch wherever you want but keep these points in mind;

• The switch(s) should be easily reached and out of direct weather exposure
• As close to the batteries a possible to keep the cable runs short
• If you must make long runs of cable use heavy gauge cable
• For 4 batteries, you probably need 2 switches as most switches (that i have seen) are for 2 battery set ups (called "banks"). This will permit you to select individual batteries to be used w/o impacting the others.

These are just a few of the things to think about, others will have some additional advise.