1999 VW Beetle: battery dies after each use

So Thursday, I had to call AAA to jump my car. Drove it around for 30 minutes then came back home. Friday about 24 hrs later when I wanted to use the car again, the battery was dead again. Jumped it Sunday adn dropped it off at the mechanic, they had to jump it again this morning to get it into teh garage. They checked the alternator, starter, battery, residual drain on the battery, and everything checked out fine. They aren’t sure why the battery keeps dying yet. Any suggestions?

Something should not have turned out fine. One of those things is the problem. How old is the battery?

battery is fairly new…2 years maybe. I have had the car 6 years and have already replaced the batter 2 or 3 times.

You have your car with a mechanic and they cannot diagnois one of the most basic systems on the car? what comes to mind? your mechanic is not worth squat.