Hi kona12,
If the isolator for the "house" battery bank is diode based, then very little in the way of charging will happen, because typically there is about 0.7 volts on the "house" side of the device.
The alternator circuit senses the chassis battery. When that battery is full power output is scaled way back. 13.2 - 0.7 = 12.5 volts = little or no charging.
If there is a continuous duty relay things are a bit better.
Another issue is the length of wire and the thickness from the alternator to the house bank. To get great charging you may need to upgrade to #4 wire, rather than the puny size in the seven pin connector.
It is possible to add a second regulator for the "house" bank. This requires modifying the alternator.