Deep Cycle Battery Heating Up When Charging

You may have accumulated sulfate from sitting in discharged condition....

" An overly discharged battery may need to be cycled a few times before it can recover fully.

• If a battery begins to heat before coming up to a full state of charge, it may be necessary to discharge the battery and recharge it a few times. This charge and discharge cycle may help the current acceptance of the battery and facilitate its recovery to a usable condition."
• http://www.batteriesnorthwest.com/batteryschool.cfm?TID=2

I've had good luck recovering batteries using a charger that has a "desulfate" cycle, and then trickle charges and maintains when fully charged.

I can't seem to get it to charge, when I do charge, it accepts current no problem. When I tried again today it heated up and the electrolyte almost came out the tops of some cells. The sg of the acid is 1.21.I am trying to cycle it to see if I can solve the problem.

The fact that it will allow current to pass through it does not mean that it is "charging." Current will pass through it due to internal shorts (which you mention) and electrolysis of the water in the electrolyte, resulting in hydrogen & oxygen evolution. Any internal shorts will result in heat (I²R watts) being generated, just like any electrical resistance. It sounds like the current is not converting Pb⁺⁺ to Pb (metal) at the anode and Pb⁺⁺ to Pb⁴⁺ (PbO₂ lead dioxide) at the cathode. Perhaps, as others suggest, the plates are sulphated up, or the electrodes are just too damaged to undergo the charging reaction.

its smoked,, test with one of these next time

If you are not happy, contact the seller directly and then ebay if needed.

Ebay is very strict with sellers and will not tolerate any fraud.

With as many problems you have had, problems you are currently having and potential problems in the future, don't take the thing to a scrap yard and get a few bucks for it and use that as the beginning of your "new battery fund".

You have a potential time bomb on your hands. If it cracks or is subject to rapid expansion you could get hurt very badly. Sulfuric acid does not burn the eyes, it dissolves them! There are many people who have skin burns where the skin becomes colorless from Sulfuric Acid. In high school chemistry someone else's apparatus with sulfuric acid blew up. Fortunately no one was critically burned but there are several of us who still have traces of burns from it. Sulfuric acid burns also take an extraordinary long length of time to heal. Much longer than thermal burns, cuts or "road rash".

Whatever you are trying to do is not worth the risk to your and other's health.

Good Luck, Old Salt

I was thinking about emptying all the acid out and re building it with solid lead plante plates. I don't think the battery is sulfated, I think that it has internal soft shorts in all cells or water was spilled out and the sg of the acid is too low when I added more water.

I would need a lead melting pot and would have to make plate shaped moulds or maybe use thick lead sheet.

My answer is still the same: Get rid of the dangerous thing! What if your next attempts fail? What is going to happen? How much will you have invested in it?

Take it intact to the junk yard and get a few dollars for it. They send them away to a processer who knows how to and can safely recover the lead and acid safely. Take this money and start a "new battery fund".

The risk of an impaired life is not worth the risk? Is your life worth what you are saving. Seemingly good batteries explode every day. What will one with a poor history do?

Good Luck, Old Salt

Battery has been sent for recycling. I drained out the acid to use for other batteries as I will be making ones with solid lead plates. I then rinsed it out with tap water a few times to remove the acidity before cutting open one cell and pulling out the plates. The positive plates just fell apart but the negative ones looked only a little cracked in places. The separators were also good so I will keep them for another project.