What size battery for Two AB XFL 15's.

[TrillGates2k6]

Let's see here, 150 AMP Alternator minus 45 AMPS for the vehicle leaves him with about 95 AMPS which is only good for about 1,368 Watts "IF" he can keep his voltage level at 14.4 volts, which he will not be able to because he's trying to push 4,000 watts; 4,000 Watts of power is roughly around 307 AMPS give or take; So 307 AMPS - 95 AMPS = 212 AMPS he has to make up for just in batteries alone; He would need about (2) 120 AH batteries to compensate for that which would put him at 240 AH running them in parallel. So unless he buy's (2) batteries, the system is gonna experience serious voltage drops and it's gonna kill his battery pretty quick

This was just a quick estimate assuming the AMPLIFIER was 100% efficient, which we all know isn't true; So, just FYI