[prairieschooner]

Jennifer,
I agree with Tom and Richard here, take the Coach to a shop that will do a load test on all Batteries or have them look at your Hydrometer. 13.2 Volts DC seems like the DC Batteries are Fully Charged.
Richard,
Yes, I am a Member of ABYC (American Boat and Yacht Council) and I do have a copy of the Current Recommended Standards. I use these Standards every day that I work, I use the current ABYC, USCG (United States Coast Guard) and NFPA (National Fore Protection Association) Standards in my inspections of Yachts as required by all Underwriters. These Standards are what is accepted as the Standards of the Industry. The Manual is about 2" thick and covers all of the aspects of Yachts, Engine Installations, Tankage - Fuels and Water, Heaters, Electrical, etc. If you have a question I would be glad to look it up but Source Isolation is a Basic Standard, intermingling of Power Sources can be very Dangerous. Our '82 has the Relays that perform this duty and you may remember me repairing these shortly after I bought our Prairie Schooner.