You should not be seeing voltage problems for only 300 watts. Sounds like your battery has a dead cell in it (i've had problems like yours before and a dead cell was the cause.). I would look into replacing your battery first
Quote (Slayer_slays_motley @ Mar 25 2012 01:40pm)
u could get 2 250 amp alts for that bro lol
battery and alt probably looking around 250-300
A single 250 amp alternator for my car is about $600, 270 amp is about 700.