there are several elements to your question for a decent answer. To know the output of the Alternator would be nice. When I bought my coach I had an alt. that output 95 amps it was hard to run the accesories such as Refer., furnace and other power draws. When I canged the Alternator I put in a 130 amp oneand have had no problems since. If your alternator is charging the house batteries you most likeley have a battery Isolator . The charge line from the Alt. will come into the isolater and be distibuted to the coach andchasis batteries. If ther is an Isotaor then you should see about 14.5 volts coming in and you can mesure at each distribution post what is going out.. Although your question is a simple one the answer may require more information about your set-up