Q. I own a 2002 Volkswagen Passat. In May I had trouble starting my car after it had been parked for 2 days. I called my auto club and asked that they send someone out to get my car started and also to check my battery. I had the original battery replaced in January 2007 by the auto club and their battery had a three-year warranty.

The service technician checked the battery with a portable battery meter and said that the battery was fine and gave me a jump start. He said to let the car run for at least 30 minutes until the battery charged, which I did.

Later, it again wouldn't start, so I called the auto club and got another jump start. The auto club said that more than likely the problem was with the car's charging system. The next day I took it to the dealership for service. They checked the car over and said that the battery was the problem.

I called the auto club and they sent out the service technician who, with his dandy portable battery meter, checked the battery and said again that it was OK. The dealership charged the battery and called me later to say that the battery wouldn't hold a proper charge. I told them to replace the battery since they indicated that the car's charging system was not at fault.

The car has worked fine ever since and it's been about three months. I filed a complaint with the auto club. They sent the technician out to check the old battery again and he said that the old battery was OK, and the company could not compensate me for the new battery. Could you give me your opinion as to what you think the problem might be?

A. It's pretty clear replacement of the battery solved your problem. There are two accepted ways to test a battery. One is to charge it fully and load the battery at half of its cold cranking amp rating for 15 seconds. If the battery holds the correct temperature compensated voltage, it's considered OK. The other test involves checking the battery's cells for proper conductance with a portable tester. This method is highly accurate and doesn't require the battery to be fully charged.

Both tests are only as good as the technician performing them and neither is absolutely reliable. My students check batteries both ways, and perhaps one in 50 times a sizeable discrepancy occurs. It's difficult to say whether the auto club tech used a portable load or conductance tester, but the fault within the old battery may be eluding detection with his tool or method. It's also possible a poor cable connection was the actual problem, which was inadvertently fixed during battery replacement.

My one concern is it seems a parasitic load test was not performed. This checks to see if a glove box light or similar hidden demon is slowly draining the battery while the vehicle is parked. If it's sometimes several days or more between driving, one could encounter a hard or no-start situation. A parasitic drain can also dramatically shorten battery life.

I'd complain again to the auto club, and insist on a third part test of the battery, perhaps using both methods. If the battery tests bad, they should cover your replacement cost.