Mike, What is the voltage in your house batteries when on shore power? and what is the voltage after you unplug the shore cord? You state that your Xantrex SW-2000 shuts down when you start the coach. That model has no provision for an ignition lock out. The inverter/converter has a pass-thru circuit when on shore power and when you unplug the inverter circuit should come if it was in the stand-by mode. Incidentally, I believe that unit has a 3 year warranty I think if the unit has an issue. Hope this helps, Fred