Thanks railtrailers, sounds like the same problem, except that my voltage dropped down to about 9v after several hours on the road. I stopped and connecter the house batteries in parallel so the house charger would hold the voltage up until I got home.
Have checked all connection except on the Alternator at this point, removed batteries and checked them as well. Been busy but my next job is to look under the bed. I replaced the air filter once but had a hard time sealing off the engine compartment so fumes didn't come in while driving. Don't look forward to getting back in there.