I have an 87 Chevy Nova. A month ago, the car died. It didn't make any sound when I went to turn it on. No idiot light came on. I had it jumped and I had the battery checked and the alternator checked and the mechanic told me it was the battery (a bad cell) and the alternator was fine. That it wasn't crucial and I could possibly get away with the bad battery in the hot weather for a while. It worked for a few days, and then died again.
So I got a new battery at Walmart for less than $40.00. That was on the 10th. I've been driving the car fine for the last two weeks. This afternoon, after sitting for about 20 hours at the most, the car was dead. Again, no sound at all when I went to turn it on. I took it back to the first mechanic and he said this battery also had a bad cell, and that it was a cheap battery (walmart) and to buy a different one. He didn't recheck my alternator. I drove it around for 20 minutes to recharge the battery (or so I think......).
It started up again fine a few hours later, I drove it to Walmart (a 20 minute drive). They tested it and said the battery was fine, it had to be a short or the alternator. Still no idiot light came on.
Here's my question. How did the battery recharge itself on that 20 minute drive if the alternator is bad? Isn't it the alternator which would've recharged the battery? If the alternator was bad -wouldn't the battery's charge been even lower after the drive to Walmart (didn't use the a/c or the radio btw).
What's my next step? Could it be a short? Or could I have just gotten two bad batteries in a row? If it's a bad battery, would it have completely recharged itself? And why would it drive fine for 2 weeks and then just die overnight?