Sounds like no charging at the engine batteries. Ten minutes running the engine is not enough to recharge it. If you have an Echo Charger (some Vansco coaches have added it), the inline fuse is probably bad. It is near the batteries (glass fuse). More likely it is the oft defective solenoid, as described in multiple, multiple threads. It allows the charger on you inverter to charge the engine batteries after the house batteries are full, (just like an Echo Charger). Search for Fatboy or Trombetta. You'll get lots of hits.
2003 Alpine 40FDTS (400HP)
Long Beach, CA