Battery has only ever gone flat once, and then i got a new one...turned out my old one was ok though... but never happeend agian
battery terminals are totally clean, power windows are the only thing..can't really think of anything else that would draw power?
my head unit dims when i turn my volume up to a certain level as well. and no, not when it's EXTREMELY high either. this is at a level where music is still clear and louder than average listening level but not HEAPS loud.