what can cause a battery to discharge, not connected to the car.

[holden j caufield]

Have a battery that has a 7 year warranty, I'm on year 4 or 5. I didn't drive it much and forgot to put on a trickle charger.

I try to start it one day and it doesn't crank, and there is corrosion around the terminals.

I pull it out and connect a trickle charger to it. Leave it for a few days and it reads 12.7 so I put it in the car, it starts and I drive off. I leave it for a few days and it won't start again. Pull the battery and charge it again, it measures 12.7 but while I have the multimeter on it, it drops fast. 12.69, 12.68 etc. If I leave it for 100 seconds it'd drop down to 11.7v

Is there something I can do or is the battery toast.

 

[jaedaliu]

If it's sealed, it sounds toast. Maybe a trip to autozone is in your future. 4 or 5 years is about all I get out of a 7 year warranty. Hope you have your purchase paperwork. Warranty exchanges have gotten confusing.

 

[LTC8K6]

The trickle charger is probably not enough to bring it back from dead. If you aren't driving the car very far, it's probably never getting fully charged.

It's not good to leave it sit for long periods. Allowing it to get very low shortens the life.

I'd get a new battery and when you store it, make sure it's charged and have it connected to a good maintainer like a battery tender.

 

[jagec]

All batteries have a certain degree of self-discharge. To add insult to injury, lead-acid batteries tend to sulfate if left discharged for long periods of time...which PERMANENTLY reduces capacity.

You can try an equalizing charge (short-term overcharging at 15V or so), but that battery is probably toast.

Lead-acid batteries just can't be left for long at a partial charge.

 

[EagleKeeper]

If it's sealed, it sounds toast. Maybe a trip to autozone is in your future. 4 or 5 years is about all I get out of a 7 year warranty. Hope you have your purchase paperwork. Warranty exchanges have gotten confusing.

Many batteries have a date stamp embedded into the case in one form or another. That can be used to argue warranty.

Especially if the battery was purchased fir you as a gift.

 

[Raizinman]

Many batteries have a date stamp embedded into the case in one form or another. That can be used to argue warranty.

Especially if the battery was purchased fir you as a gift.

The code is a letter and a number. For example: A3 would be January 2013. B2 would be February 2012. F0 would be June 2010. You will find this code normally melted into the side of the top cover. Often there is a sticker with this code too. Keep in mind that the melted code is the manufacture date. The sticker is not always the manufacture date.

 

[desy]

at 11.7 sounds like one cell is toast usually charged should be like 13.5
If its 5 yrs and your in a hot area I wouldn't be surprised heat kills batteries

 

[BUTCH1]

at 11.7 sounds like one cell is toast usually charged should be like 13.5
If its 5 yrs and your in a hot area I wouldn't be surprised heat kills batteries

Yup, I average 3yrs here in FL no matter what the car.

 

[fuzzybabybunny]

Having gone through lots of batteries and gone through the same exact "sitting around for a year" scenario, the battery is toast. I even bought a normal amperage charger and a desulfator that I hooked on for a week straight.

Still dead.

And the warranty paperwork must be in hand. The actual original paper from years past.