Battery issue/question

[Tonyvdb]

So today I started a couple of my tractors that have set all winter, two started right up, 3410 and 7117. The other 7117 battery was almost dead just clicked a little and tried to turn over the motor. Put a charger on it and it sparked big time like a direct short, took it out and brought into the heated garage and tried another charger, same thing. Put a volt meter on it and it only had 4 volts and it showed -4 meaning the volt meter was connected backwards but it wasn't. Hooked up a charger again only backwards and it started charging like normal. What would cause this, is it possible for the + to become the ground? Can I change it back? Pretty sure it was installed correctly + to starter and - to ground before and it ran fine all last summer. I'm at a loss on this one.

[skunkhome]

I believe you can count that one as dead. I think that can happen when the electrolite get so diluted due to the loss of charge for a long period that the sulphates react with the lead plates and the plating on the cathode and anode are the same and can react in reverse. These batteries are very unstable and can fill up with hydrogen and suddenly explode blowing the tops of of one or more cells. I've seen them blow just moving them around the shop.

[Tonyvdb]

Thanks for the information Phil, that doesn't sound like a good thing, guess I'll just replace it and be done with it.

[Willy]

Hook up a alight or something to drain the battery completely

Then recharge.

Back in the olden days when I was young the Fords had a pos.

ground,It was easy to hook the charger up bass ackwards.

Then we would have to leave the headlights on until the

battery was dead. A slow charge is best if you have a choice,

it never seamed to hurt the battery any.

[MikeES]

To reverse the polarity, not only do you need to drain it down to 0 volts, you will need an older low amperage charger that does not have any "smarts". Newer style chargers will not work because they are smart enough to know if you have hooked up the charger backwards, and they will not charge a 0 volt battery because of no polarity reference.

[Willy]

Sometime you can fool them by hooking up your charger

then jump a good battery to it for a second.

the charger isn't as smart as it thinks it is:D:D.

[bigten65]

I have saved a couple of batteries, by dropping them on the concrete floor from about 12 or so inches. It helps to dislodge the crap from in between the plates.

[Tonyvdb]

Thanks guys, I'll give that a try before junking it. I have an older charger and a newer one that has an activate switch on it that gives a dead battery a little zap to get it charging.

[Tonyvdb]

Mike S get the prize, I took his advice and hooked a tail light bulb up to the battery and left it on over night, the battery was flat dead in the morning. Hooked up a charger and it didn't start charging so took Willy's advice and jumped a good battery to it and it started charging. Charged it at 2 amps for two days, put it in the tractor and it started right up. Been holding a charge for almost two weeks now. Thanks guys for the advice you saved me around $70 bucks for a new battery at least for awhile. Always good advice here.

Thanks Tony