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Battey trouble

I installed a new battery in my 2002 Ford Escort, started it and turned it off. A week later it was dead. I jumped it and let it charge for 20 min. I drove 1 mile and the car died. I then jumped it again and it died as I entered my driveway. I took the battery to the autoparts store and the store employee noticed the battery had swelled and I was told it had been overcharged. I had the alternator tested and it was fine. Could the battery have frozen? It’s been very cold here. If it didn’t freeze what sort of electrical problem could cause this? I’m worried if I put a new battery in the same thing will happen again. Ideas? Thanks.

Did they test the alternator in the car or on the bench? If in the car, did they rev the engine? I put a faulty reman alt in my wife’s car that tested Ok, but was flashing the battery light as she drove. Turns out a bad regulator was allowing the voltage to spike to 16v when the rpms were above 2500. I was able to demonstrate that to the parts store and get a warranty replacement, because their benchtester kept saying it was good.

On the bench. Hooked it up to testing machine.

Yeah, the benchtesters only spin the alternator to just above idle. Most charging system tests also run at idle. But, a bad regulator may not show it’s ugly head until the alternator is spun faster. I put a voltmeter on my battery and rev’ed up the engine to see the voltage spike up.

You may have an excessive current drain on the battery if the car was parked for an extended time period and wasn’t started. A low charged battery will freeze and cause damage to it. Normal current draw on the battery while the car is parked should be less than 50 milliamps. Another possibility is the alternator is putting out excessive AC ripple voltage and that caused damage to the battery. Unless the shop was checking for that that they may have missed that possibility. Checking the alternator while it is installed in the car is the best way to check it out.

Thanks for the input. These ideas will definitly help to chart my next course of action.

Take your next new battery for a 15-20 minute drive before putting it to bed. Cougar’s thought about the low charge was my first thought as well.

My thoughts too. I’ll try it. Fingers crossed. Thanks to you all.