I have a 2007 Mazda 3 with about 10,000 miles on it. The car worked perfectly for 2 1/2 years. The battery drained for the first time while I was away on vacation for 1 1/2 weeks during August 2009. It was replaced and all was fine until the end of October when it drained again. The dealer replaced the battery and the alternator, and the car worked for awhile, but the battery drained again in early December. The dealer told me the battery had a "bad cell" and replaced it. This morning (only 2 weeks later) the battery was completely drained again.

The dealer acts like this is my fault. They keep asking if I "left something on." They also suggested that I don't drive the car enough. I take public transit to work during the week, so I only drive on weekends. Is it too much to ask that a car battery holds a charge for 1 week?

From my research on this message board and others, I can see that the issue of frequent battery drains is not an uncommon problem. It seems this can happen with any car brand. I don't understand why the Mazda dealer doesn't seem to have the tools or the motivation to diagnose and fix the problem!