"Kenwood KAC-PS301T 2x200w amp driving subs
Kenwood KAC-PS501F 4x150w amp driving fronts and rears"
from what i can gather, you are only running 350 watts RMS, which isnt very much at all. i think something is wrong.
and unless you are getting a battery light warning, then there is nothing wrong with your alternator. i'm sure it can handle at least 500 watts.