Anyone ever had a battery die enroute with a good alternator?

My son is on his way to southern MO, about a five hour trip. He’s driving a '97 Pontiac Grand Am with a 3.1L engine. He called to say that he had a check engine light on. That by itself is usually not a big problem. 20 minutes later he called to say his ABS light and battery symbol (charge) lights had come on. Sounds like low voltage, I said from 160 miles away. Find an Autozone to check the alternator for you. He did. They said his battery, which would no longer crank the car at that point, had gone bad. I’ve never had a battery die while a car was being driven, as long as the alternator was good. Anyone ever had one go bad as long as it was being driven and adequately charged? Shoot, the car should run fine on the alternator alone, even if the battery is deceased. SOOOOO he paid for a new battery and installed it in their parking lot. He still had the same battery symbol light. I told him to have them recheck it. They said the alternator was putting out only 25 amps under load. Not good. He needs an alternator. 25 amps won’t run the lights and computer and keep the battery charged for the next start. I feel that they should give him his good battery back and sell him an alternator. THEY blew the diagnosis. He can install it as soon as it’s daylight.

He probably doesn’t want the old battery back. Every time I have run a battery completely flat due to a bad alternator, the battery has died within a short time anyway. He’s better off completing his trip with a new battery and alternator.

I agree that the alternator died first, then the battery got rundown. But, if the battery was 4 years old or more, I’d replace it anyway. It may or may not hold a charge, but why chance it if the battery is suspect as well?

Even a new battery might not survive. A few months ago I had an alternator fail about 1000 miles from home, resulting in the battery going completely dead. I had a local shop replace the alternator and charge the battery (which was less than one year old), then I drove home. The battery held up during the drive, but died about two days latter. Batteries really don’t like going completely dead.

He is better off replacing both the alternator and the battery. The old battery may have shorted a cell and this could have caused the alternator to fail trying to charge a faulty battery with the extra high load.

I don’t know how they tested the battery but considering it was run way down the battery should be put on a charger for at least an hour before even testing it.
Failure to do this means a worthless test.

Where’s he at in MO? Just wondering because I have a long time friend (30 years as a tech and parts man) up there who may be able to help him out if he needs any assistance. Friend is near Cross Timbers, about 50 miles north of Springfield.

Most parts house people are only marginally familiar with testing and diagnosing complaints and the equipment they use, although impressive in appearence, isn’t up to the task. Minumum wage won’t buy much in the way of technical proficiency. Like they say, you get what you pay for. But I will agree that the battery had little dependable service left, so in your case, be thankfull.

But then, you already knew that, I’m sure.

And also, a battery with warped plates can toast an alternator while keeping the voltage below the 11v+/- necessary for the ECM to function.

Thanks for the offer ok, but he hadn’t quite made it out of KS when he called. He’s headed for Shell Knob to see how much ice there is on Table Rock Res at New Years. Personally I think he should have stayed home, but neither he nor his wife have to work until Thursday. He will be on his way again this morning after installing a new alternator.

Yes, batteries don’t like to get completely run down, but of course his wasn’t COMPLETELY run down or the car would have ceased running. It was too low to crank, but still had a little juice. Of course it failed the “load test”. It had low voltage to start with. Depending on how all this works out, I may have conversation with Autozone’s regional office. I donate enough to their worthy cause every month to have at least a little clout.

Red Knox and Cougar are right. I had a battery go bad mid trip once, shorted cell, but I was lucky it didn’t take the alternator with it. The shorted cell will eventually cause the diodes to burn out. Sounds like he only lost one diode so far.