I have a direct feed from alternator to house battery with a circuit breaker on it. Doubled 4 awg wire. This is in addition to the original OEM charging circuit which has a short length of fusible link protecting it. This link can get very warm, very quickly when house batteries are depleted.
If I Manually trip the circuit breaker the max I will is about 55 amps, when cold, and this tapers quickly as the fusible link warms. If I bring in the doubled 4 awg feed to the depleted house batteries, the current to the batteries doubles with sufficient engine rpm and will start the single V belt squealing in protest.
My biggest limiting factor is my voltage regulator located in my engine computer. It will decide willy nilly when to allow no more than 13.7 volts. While 40+ amps might have been needed to hold 14.5, just 13 amps could be needed to hold 13.7.
A 500 amp alternator and 4/0 wire would charge my batteries no quicker when all that is allowed is 13.7
