"Regarding your question about the battery Boost dash button on my Marathon. i believe that I do have the ability to connect for short periods of time the house batteries to the chassis to start the bus when the chassis batteries are down??? I am not sure how this accomplished in the system."

I'm not familiar with Marathons, but you do have to make certain you are not connecting the house and chassis batteries. Otherwise the inverter input to the house batteries is seen by the voltage regulator through that jump start circuit, and the two sets of batteries are not isolated.

I don't think you have them connected, but I want to be sure because some of what you are seeing does not make sense to me.