The Stovebolt Site Forums The Shop Area The Electrical Bay Battery on charger for a year.

The Blue Funk sat at a Body Shop, after being hit by a Semi, for about a month last year. I believe the ignition key was left in the "on" position and the battery was drained.

I pulled the battery, after the Blue Funk was towed home, and put it on a Battery Tender. Eventually, the green light came on the Tender, indicating a full charge. The battery has been on the Tender for almost a year now.

My question: Could the battery still be usable after being through a situation as described above?

Thanks.

It's possible, but more likely the battery has become "sulfated" and will need a little TLC before it's ready to go. 6 volt batteries are much more likely to recover from a long period of total discharge than 12 volts, for some reason. I reclaimed one a few years ago that had been sitting in a discharged condition in a 1950 Chevy since the mid-1980's. It worked well enough to start and run an early-50's stovebolt engine pretty frequently on a run stand in my shop for several months.

When a battery discharges, the plates inside the cells undergo a chemical change. The negative plates of a fully-charged battery are made of pure lead, the positive plates are lead dioxide, and the electrolyte is a mixture of sulfuric acid and water with a specific gravity of 1.250 to 1.265 depending on the concentration of acid the manufacturer chooses to use. As the battery discharges, both the positive and negative plates react with the acid to form lead sulfate, and the acid concentration drops. On a fully-discharged battery the liquid turns to pure water, theoretically anyway, with all the acid absorbed by the plates. No, I'm not about to put a soda straw into a battery cell and take a sip to test that theory!

Initially, that lead sulfate is a soft, spongy material, and reconverts to lead and lead dioxide easily when the battery is recharged. If the battery is left in a discharged state for a long time, the lead sulfate changes to a hard, stable crystalline form that is very hard to dissolve. Reclaiming a sulfated battery is a slow, difficult process. Put the battery on a slow charge, 5 amps or so, for several days, and check the specific gravity of the electrolyte frequently. As the sulfate dissolves, the concentration of the acid will steadily increase. When it tops out, no matter what the reading, put a slow discharge on the battery by connecting something like a headlight bulb across the posts and completely discharge it. Slow-charge again and monitor the acid strength. Discharge- - -recharge- - - -discharge- - - -recharge, etc., maybe as often as 10 times or more. Each time, a little more sulfate will dissolve. When the starter can be cranked for 15 seconds and the battery voltage stays above 4.5 volts for a 6 volt or 9.6 volts for a 12 while still cranking, the battery should be serviceable.
Jerry

Wow! Thanks, Jerry- "Everything I Ever Wanted to Know About Batteries But Was Afraid I Get Charged"!

I'm going to keep this reply of yours like I've done with the majority of the information you've given me: I'll make a hard paper copy of it, roll it into a tube, and hit myself in the head with it until the information sinks in!

Seriously- I appreciate all the electro-chemical reaction and TLC information. I will put it to good use.

Thanks again.

It has been my experience with a battery tender that if the green light is on, the battery is in top shape. As the battery ages, the cycles between green and orange increase.

why not start the truck ever once in awhile just for fun...

Could it be that with half the cells in a 6 volt battery there is half the chance for completely dead cells when comparing to a 12 volt battery?

Jeff

Just a theory of mine, with no real facts to back it up, but I think it's more likely the thickness of the individual plates. 6V battery plates tend to be thicker than their 12V counterparts because of space limitations to squeeze 6 cells into the case. If the sulfate crystals can't penetrate to the center of the plate, it's less likely to get a terminal case of "won't re-dissolve". Just a W.A.G. but it makes sense to me.
Jerry

Well Joker, (you joker, you) my truck ain't got nothin' on it but a frame with an engine, a drive train, and four wheels.

Otherwise, I'd say you had a good suggestion.

.
I like your W.A.G.'s Jerry. ............Don't take that the wrong way.

Ok. I'll bite. What is a W.A.G.?

the sort of Guess folks make here when they can't lay hands on the problem part

Bill

In British football (soccer) it means Wives And Girlfriends.

As Bill notes, Americans use is as Usage #5.

"Wild (donkey) Guess"- - - - -then there's a SWAG, when you know just a little about what you're talking about, That's a "Scientific Wild-Donkey Guess"!
Jerry

My old 51 back in the 60's had been sitting for about 3 weeks when I tried to start her. The battery was dead, dead, dead. I took off the covers and there was nothing in there (dry). I poured water in and it began to bubble. A few minutes later I tried to crank and she started up. What a surprise. Batteries are weird.
I also had two batteries on a tender for a year or so and took one off to use and even though the light was green the battery was dead. Batteries are weird.

Wild Arse Guess