2008 Hyundai Tiburon battery continuosly being drained

I drive this car on average of 20 miles per week - sometimes more. I currently have a sears diehard 8 yr battery that is just over 3 years old. I have had the car in to the dealer twice (it is still under warranty). They checked the alternator and starter and said they are ok and that the car draws.02 amps when off. If the car is not used in 2 days the battery is drained but if I charge it the car will start. Last week I drove the car 3 times for a total of approx 60 miles and after sitting for 2 days the battery was drained. I would like to know if there is something that could be sucking the battery dry. The dealers answer both times has been "That I do not drive the car enough". I have had other cars and they have sat for way longer periods of time and never had this problem. The car was new when I purchased it in 2009 but was driven to the dealer from another state and I wonder if that may have caused a problem also as I have no way of knowing how the car was driven or handled.