Okay, so I got into a little fender bender. The driver airbag popped, flat tire, lower control arm, and fender damage, but that was all. No frame damage or anything else. I towed the car home and got to replacing the damaged parts about a week later and went to turn the car on and noticed symptoms of a very low/dead battery. HUD coming on/fading off, low volume on the door chime, etc. etc. and wouldn't turn the engine over. I figured I'd left the headlights on, or door open or something, so figured I'd throw the charger on it. I connect the positive, then clamp the negative to the frame, and hear all the relays clicking and beeping (left the keys on accessory). Hmmm, strange I thought, the charger is only a 2amp slow charge, and doesn't have boost, and everything seems to be powered up, the battery must not have been dead. I crank the engine and it fired right up. Unhook the charger and let it run for a good 20 minutes. Everything seemed fine. About another week went by and I tried starting it again and again, symptoms of a weak battery. Any idea what could be causing this?