ruin battery with a charger?

[papyrus]

So a couple of weeks ago, I managed to leave the lights (yup.. HEAD lights) on overnight on my 996tt. Remarkably dumb, sure. So somewhere in the midst of jumping it, my gf's neighbor interjects. He's a nice guy, and had one of those portable minibatteries with cable. So i stumbled through the bizarre process of finding the probe in the fuse box, powering up, opening the bonnet (hood sounds like it would cover an engine), attaching to the battery, and striking out - not enough juice. SO... dude argues that a real 'jumpstart' would fail becase of some hooey about electronic fuel injection. It didn't really add up to me, but I wasn't in a hurry and he was being very helpful, so I agreed to throw the battery on a charger for a couple hours. I had personally never used a charger on anything but deep cycle marine batteries, but it seemed logical. So i did it,and it worked.

Now, a week or two later, things are weird. The battery was mostly dead on me this morning. I started the car with another battery, rehooked the original, and ran it a while. I just tried it again. Went from 14 volts to <10 sitting. Not completely dead, but it is not holding a charge at all when sitting a few hours.

Any ideas? Sure something could be shorted somewhere, but it will of course be easier to suspect the battery itself. The car only has 6800 miles and is 3 years old... Could the charger have wrecked my ish?

Thanks in advance.

[dlambert]

If the battery reads less than twelve volts it's bad, specifically one cell has shorted out . Each cell adds 2 volts to the battery. You will be able to jump start the car and drive but you are risking damage to your charging system. Replace your battery.

David

[john in lb]

If the battery reads less than twelve volts it's bad, specifically one cell has shorted out . Each cell adds 2 volts to the battery. You will be able to jump start the car and drive but you are risking damage to your charging system. Replace your battery.

David

I fully agree. 3 year old battery, went dead... these are all the signs - By the way, the dealer might actually cover it under the original warranty. (they replaced mine a couple when it was about 14 months old... said it was a courtesy change out given the low voltage reading).

[papyrus]

how long do these batteries normally last? I thought I remembered 5-10 years in the past...

[Tool Pants]

I agree with all of the above. Time to get a new battery.

"6800 miles and is 3 years old" says it all. Lead acid batteries do not like to sit being unused.

http://www.renntech.org/forums/index.php?s...50&hl=lemon

You would not buy a 5-10 year old automotive battery that had been sitting on a shelf for all those years, would you?