I recently inherited a Chevy S10 (Sorry) which is now my work truck. My 2000 F-150 Lariat 4x4 sits in the garage and is used occasionally. Recently I did not use the truck for 2 weeks and found the battery to be so low it would just "click". (This has happened twice) I took the truck to Autozone and had them do thier battery test. It checked out OK. Is this normal? Nothing was left on. I have a Ford Factory alarm installed as the only power drain. This seems way to short of a time for the battery to be dead. Any thoughts??

 

It probably isn't just the two weeks that it's been sitting there. Perhaps the journies you made before those three weeks were very short. If you only drove it, let's say, once a week before that, and then only for 3-5 minutes or so, then I would definately say that the battery needed a charge.
If you don't drive it long enough, it won't charge up. When you jump it, take it out on the highway for a good 20-30 minutes, that'll charge it right up to full!

 

I wouldn't be surprised if your battery is dead even after a full charge. My 2001 Supercrew barely starts after two weeks of sitting with a Yellow top Optima installed.