Hot Batteries

[IanJ]

I am trying to get around my battery system, and am still getting problems. I followed Maine Sails advice on a previous thread ( "Wiring and installing a battery monitor", and "Battery switch question" , and have a bank of two batteries wired to A on my battery switch, and a second battery for emergencies on B. I use a charger wired directly to one of the bank on A, and have a Blue Sea relay running off the A bank to feed the B battery. Recently I also put in a Vic BMV600 monitor, although I don't think it is properly synched yet. On my Busses, I just have the A/B Off switch, fridge and alternator hooked up.
In February I installed new Costco marine batteries on my A bank, but one of them is inordinately hot. When I tried to start the engine the other day, it would not turn over, so I had to switch to my B battery. After running the engine for about half an hour, it still didnt turn over from the A bank, althought the fridge, radio etc were running quite happily.
Do I have a dud battery? Any other ideas on this?

 

[Bill Roosa]

Not a lot to go on IanJ
I'm assuming you have 12 volt batteries and not 6 volt in series. How are the batteries hooked to each other in bank A? You say you hooked one to the charger, how does the other one get a charge?
You say you have the A/B OFF switch wired to the buss??? Not sure what you mean. The A/B off (3 way) is normaly wired before the buss not after it like an appliance switch/circuit breaker. Can you clarify please?

With all that said I'd think that if you had your bank A batts hooked up wrong there would be two hot batts not one. I'm thinking that it would be a bad battery then. You can check by disconnecting it and mesuring the voltage after about a half hour. If it is good then it should read 12.6ish volts. Anything in the 11 volt or lower range is a bad battery or the charger is not connected properly.

 

[Ron20324]

You said "and have a bank of two batteries wired to A on my battery switch", so we assume 2 batteries wired in parallel. Is your starter wired just to the B bank perchance?

"on my Busses, I just have the A/B Off switch, fridge and alternator hooked up." The starter would have to be wired to the buss, or the"out" side of the 1/2/both switch to work off either battery.

 

[IanJ]

Thanks Bill. I have two 12v batteries wired parallel ( + to +). AB Off switch is hooked to buss. So you are saying that should be between batteries and buss? Will disconnect and check voltage later today.

 

[IanJ]

My starter is wired to buss

 

[IanJ]

Correct that. My starter is wired to the A/B Off switch

 

[kenn]

if you have two 12v batteries in parallel on bank A, and only one of them gets hot AND they won't start the engine... pull them both out and get them tested at a battery shop. It's my guess that the one that gets hot is bad... but who knows.

 

[Ron20324]

Correct that. My starter is wired to the A/B Off switch

which stud?

 

[Bob J.]

I have two 12v batteries wired parallel ( + to +).

Doesn't wiring + to + = 24volts?

Bob

 

[Don S/V ILLusion]

Theories abound. If you want to KNOW whether it's a bad battery which is possible, do as Kenn suggested. Even if it wasn't "bad" before, overheating it, regardless of the cause, likely did damage making it un-useable now and just another fault in your electrical system.

 

[Roger Long]

PLEASE! Handle these batteries with goggles, protection, and wash down means available. Damaged batteries can and do explode. They should actually always be handled that way.

A friend took a battery out of a boat because it wasn't behaving right and it blew up in his face when he set it down on the dock. Two weeks in the hospital but he was lucky and didn't lose his sight.

 

[Scott B]

I have two 12v batteries wired parallel ( + to +).

Doesn't wiring + to + = 24volts?

Bob

12v + to + = 12v

6v + to - = 12v

 

[Ron20324]

I have two 12v batteries wired parallel ( + to +). Doesn't wiring + to + = 24volts? Bob

No, the battery's + to +, - to -, = 12 volts, double the amphours.

To get 24 volts you'd wire in SERIES, one battery + to the other's -.

The A bank is both new batteries, the same type/size?

 

[Bob J.]

Well that would explain why I fried the trolling motor on the bass boat........

Bob

 

[Bill Roosa]

Hey Ian
take both batts down to the auto parts store and have them checked. The bad hot one no doubt took the good one with it or at least shortened its life some.
The proper (for what you apperantly have there is no real proper) connection should be batt + to term 1 of 3way, bat + (other bank) to term 2 of 3 way, C terminal of 3 way to power buss, and grounds on all batteries hooked together (both banks).

 

[IanJ]

Thanks Bill, will do. Pretty much how it is set up. This thread is getting a little out of control!

 

[FourPoints]

@IanJ - if you could post a schematic of how everything is hooked up it would make things much easier to troubleshoot.

 

[IanJ]

Brian. Pretty sure this is how it is right now. Removed fried battery, but wondering what caused it after only one year.

 

[Ron20324]

I just installed the Vic600. You have it wired wrong. Look back at the manual and Main Sails posting on battery monitors.

Every wire that makes elctricity or uses electricity goes to the load side of the shunt. ONLY the battery neg cables go to the battery side- nothing else.

 

[IanJ]

Ron. You are right, and I forgot that when I did the drawing. I do have it hooked up to the shunt, pre everything else, exactly as Maine Sail an you suggest.