My bro has replaced his battery in his 90 civic twice in the last year. It goes fine for a while and then starts having to jump it off every single time he needs to drive it. Car runs fine once its jumped. WTF? anyone have any ideas? No lights stay on and no car alarm.

 

How many volts are you getting at the battery when the motor is at idle? it sounds like the alternator is almost good but not good enough.
Also it could be a short somewhere.

 

yeah i need to measure voltage, i never see him and never have time.