After fighting heavy traffic at the end of a ten-hour day, in darkness and rain, the last thing I needed upon arriving in my hostess's driveway was another* system problem.
Every circuit I plugged into popped; it was my lawyer wife
who solved the mystery: since she'd been wrapped under an electric throw powered by the inverter, she'd drained the batteries. Powering up, the charger was demanding more than the 14-15 amps whose sustained load would trip our host's 20A service. Sure enough, twenty minutes on the generator made us "plug-in capable" again.
An alternative that might work, if the demand isn't too high: plug in with the battery disconnect aka Salesman Switch
positioned to OFF. After ten minutes or so, turn the switch back on and gingerly increase the load.
At present, I've got Aqua Hot on, all three zones set to Furnace, and my draw at the moment is 1 amp.
*The dashboard looked like a %^&#'ing Christmas tree on the last stretch: road dirt had impeded the magnetic switch for the step-out detector, so I had that light and attendant beeping. Two TPMS sensors weren't reading; so, the red light was flashing on the Tire Traker. As often happens in heavy rain, the Water In Fuel light was on. Then, there was the persistent Check Engine that illuminates every time a valve selenoid on my C13 hiccups. I was the RV version of the fabled B-17 that limped back to England sans half its vertical fin.