Let me add a bit more here that I just read about:
amp = watt/volts
So, I would need at least a 125a relay because 1500w(size of my amplifier)/12volts = 125a.
Now, looking for a relay this large is pretty easy, but they seem to be very power hungry using up to 2.9watts or more just to power the coil in the relay. So, if I were to use the 5volt line coming out of the carnetix, to power the coil used in this relay, would that be too much for the carnetix? I'd need at least two of these relays (one for each amp) so that'd be about 6 watts coming from the 5volt line. Any input on this?