While we were out running errands yesterday, our car failed to start after a half hour stop at one of our destinations. The first attempt to start the car resulted in nothing but a rapid clicking noise. The second attempt was a single click and then nothing. After turning everything off (head lights, air, etc) and letting it sit for about 5-10 minutes, it started fine.
We drove it to Walmart to see if they could test the battery. They tested it and said it was good. The recommended that we go to Autozone to have them test the alternator which we did. Autozone said the battery and starter were fine but that the alternator was bad.
We took it to a mechanic (we're new to our current area so it was the first time we've been to this mechanic but they have good reviews). They ran tests and said that the alternator was fine. After more tests they said the only thing they could see was that the battery's cells were all weak which would result in intermittent issues.
I went back to Autozone at this point (a different Autozone), and before buying the battery they ran the tests again. This time their tests showed that the battery, starter, and alternator were all fine.
So we've had 3 tests say that the battery was good plus 1 test saying it was good but had weak cells. We've had 2 tests say the alternator was good but one said it was bad. We're not sure exactly which of these tests to believe at this point. There has only been one incident where it failed to start and its worked fine since then (we've started it nearly a half dozen times since it failed with no apparent problems). The only thing that I can think of is that maybe the battery died because it had been turned off and on approximately half a dozen times with little driving each time right before it failed due to the fact that we took it to get the tires rotated and balanced.
Should we replace the battery? Take it to another mechanic?