'86 corolla electric problem

My problem started a few days ago when i was driving my car, and the stereo, headlights, and engine started to dim and eventually die. I had the car towed home and my dad and i had a look and determined the problem was a wire that goes from the alternator to the battery. After fixing that I charged up the battery and tried turning on the car the next day, and i heard clicks and things that meant i wasnt getting enough power. I took my battery to Schucks to have it tested and its fine. My car starts right up with a fresh charge or by jumper cables, but when i left the battery in the car for a couple days it lost all charge, and i dont get any response when i turn the key now, not even clicks. My question is whats draining my battery's charge when the car isnt in use and how do i fix it. I know i'm not leaving my lights on or anything too simple like that.