dead battery( 9 only in garage- 3 times)

What is your question?

3 times I went out to start my tahoe and twice the battery was way dead 3% battery life on Schumacher battery tester. The third time about 6 mos latter when i opened the door all I heard was a lot off clicking in the door like the locks and windows and computer couldn't figure out what was wrong. this happened in Dec. 2010 in Juneof 10 and March 0f 11(after a new battery in Dec.10, I am still having these problems-local garage had it for 3 days and couldn't find a thing wrong.--help please e-mail me if you have an answer.pstupar@tds.net