Paralel batteries, charging

[LubeDude]

We have two 12Volt gell batteries wired in paralel in a 21" Lavey Craft 454. I have looked all over the internet and received many thoughts and Ideas on this question. I have the same setup in my own boat, but with regular batteries. I charge them together buy just putting the charger on the one battery and let them equal out in my own boat, but when I do that on the Lavey Craft it keeps kicking the charger off. Ive read that the batteries will not really charge the same by some.<br /><br />Basically it should work. Ive heard that there are people that use a dual charger and hook one set of leads on one battery and one set on the other, leaving them hooked together, and everything in between, including disconnecting and charging separatly. Whats your thoughts?

 

[Drowned Rat]

Re: Paralel batteries, charging

LubeDude. When your charger trips, are you trying to charge the batteries at the 10A setting or higher? The 2 batteries together are trying to draw too much amperage from the charger and that's why it's tripping. You should be able to charge on the 2A setting without that problem. As for the ideal method, I believe it's better to charge the batteries separately when disconnected. If you want to leave them connected when charging, don't put both charger clips on one battery. Put the negative charger cable on the neg. post of one battery and the positive charger cable on the pos. post of the other battery. This way the batteries will equilize properly. This is actually good for the batteries and should be performed every once in a while even if you usually charge them separately. Note: use this method only for parallel setups. Hope this helps.

 

[LubeDude]

Re: Paralel batteries, charging

Thanks Drowned rat:<br /><br />My boat uses this setup for the trolling motor batteries and I havnt had any problems, but I have thought about hooking it up that way for the very reason you mentioned. The Lavey Craft has this set up due to the hard cranking of the 454 engine. Not probably the way I would have done it, and may change it in the near future when I have the time. However, this morning when I got to work, after leaving the automatic 10 amp charger on the second battery overnight, (disconnected from each other) The battery was too hot to touch and was bubblimg. Yes, a bubbling dry cell, Lucky it didnt blow up. Its not the charger, as I checked it on another battery this morning, and it shut off like it should. Looks like a battery failure that caused the severe amperage draw.

 

[Drowned Rat]

Re: Paralel batteries, charging

Makes sense to me. Glad you figured it out.

 

[LubeDude]

Re: Paralel batteries, charging

Just got back from NAPA. They didnt want to exchange it as it had 13 Volts and said it was ok, and tried to blame it on the charger which I bought from them yesterday, then they were quiet about the charger but insisted the battery was fine and that I should have only charged it at 2 amps. I then took the battery to a Battery exchange just accross the street and showed it to them and explained what was happening. They tested it and said it had a dead short in it. I then had them call the NAPA store and explain it to them and then took the battery back to NAPA and they gave me another battery. So finally all turned out well.

 

[Drowned Rat]

Re: Paralel batteries, charging

Next time dump a boiling battery on their counter and ask them if it's supposed to do that.

 

[LubeDude]

Re: Paralel batteries, charging

Thats pretty much what I did, it was still venting and still pretty warm. I wouldnt have wanted a spark anywhere around it. I do a lot of business with these boys, and really didnt expect a problem. They just do not know batteries very well, or have the equipment to really test them.