I did a brief experiment using my inverter to power my Schumacher to send 12 amps into another battery. It was using nearly 25 amps from one battery to send ~13 amps into the other.
What a waste, even if the alternator is providing the juice to power the inverter.
My Voltage regulator is controlled by my engine computer. It arbitrarily decides that 13.7v is plenty and the amps needed to hold 13.7 can be 1/3 the amps required to hold 14.5. While I have seen over 100 amps from my alternator when cold with depleted batteries, it never lasted very long and 13.7 always came well before the house battery approached 80%, and my house batteries are on a shorter circuit path than is my engine battery.
I've kind of given up on getting anything more out of my alternator. The fatter cabling I added ensures I do get some high initial amps but 13.7v does not do nearly as much.
