Last Friday, I was driving with my headlights on. After a few minutes, the radio went dead. I turned the headlights off, and the radio came on. I turned the headlights on again, and the radio went dead. After that, I drove with the headlights off. I assumed the problem was the alternator.
This past Tuesday, I took the car to my regular repair shop. Wednesday morning, I called, and they said the problem was the battery, and they put in a new battery.
This doesn’t make sense to me. I hadn’t had any trouble starting the car, which I thought I would if the battery was low. As long as the car was running, shouldn’t the alternator have kept the battery charged, even with the headlights on? And after I turned the headlights off, the alternator seemed to recharge the battery with no difficulty. Between Friday and Tuesday, I had no problems with the car (I never used the headlights). It started OK and it ran OK.
Any thoughts on this?