I currently have a 92 civic and have a sony 1000 watt amp, about 300 rms, with two 12 inch subs, about 300 rms each, plus an alarm and every battery I get for my car only seems to last about 4 months and I was wondering what is the best way for me make my batteries last longer (I've tried all different types of battery brands). I was thinking about purchasing a capacitor, and if this is a solution what is the best one to get?

 

Check for a parsitic draw on the battery. Do you sometimes have to jump start your car?