Help understanding battery problem

24 May 2013
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United Kingdom
Please bear with me, I'm new here.

My girlfriend's car battery died at Christmas due to being 6 years old and being left on a driveway for weeks in the frost. Bought and fitted new battery and all is good for five months. Drove car last Sunday fine. Tried to start it on Wednesday and battery is dead. Battery measures 0.22Vdc out of circuit.

Fitted new battery and all is good. Measured 13.76Vdc and climbing with the engin running so appears to be charging.

I don't have an ammeter to hand so can't measure the current drain with the engin off but will check this when I borrow my DMM from work on Tuesday but (fingers crossed) I'm hoping it will be ok. Will check it later on just to make sure.

The question is, what causes the battery voltage to drop to 0.22V. Even if there was cell damage it should still read higher than that. Is there some internal fuse I don't know about. It is a sealed battery, there is no damage to the casing and no signs of outgassing or corrosion.

I am hoping someone can help me understand the failure mode at work here.
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A failure that soon could be called infant mortality and that type of failure is attributed to factory defects.
Fitted new battery and all is good. Measured 13.76Vdc and climbing with the engin running so appears to be charging.
But climbing to what? If too high you could be overcharging the battery.
Yes, a bad/faulty battery unless you left something switched on in the car? Yes as above it should stop charging at approximately 14.7 volts
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I'll recommend checking the current drain when the engine is off too to see if something has gone wrong in the car.
Connect the ammeter leads before parting the battery terminal, then if something is temperamental it doesn't get chance to power down.
I have known things such as stereos, amps, immobilisers, lights, alternators (charging OK but drains the battery when stood still) cause this sort of issue. Then again it could just be a dud battery!
I let the car idle for about an hour and then switched it off and left it for another couple of hours. The new battery measures 12.43V in circuit and now reads 14.47V charging so all appears good. I'll check it again in the morning to make sure. I reckon it is a bad battery as well but I'm no expert and thought I would try some people who have more experience of these things.

Now I have to try and get a refund from "The Battery Guys". I'll stick to using local parts suppliers in the future I think.
Lead acid should be about 2.105 x 6 volts with no surface charge at normal temps. To remove the surface charge after charging leave the lights on for a minute or so.
RUN, DO NOT WALK back to the supplier !! Under EU consumer laws a failure under six months is down to them unless they can prove different ( next-to-impossible) After that the onus moves towards the consumer.
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