Reason I said check the converter/inverter/charger was from an experience three months or so ago. When we had plugged in a small heater in front recepticale. When the convection oven was turned on or the coffeemaker all the ac ac circuits including tv, microwave convection etc also went dead. Breakers, in our revolution for house ac is at foot of the bed.
Two 15 amp breakers for tow 15 amp circuits. Neither was tripped. Cutting on generator caused weird behavior and noise. Inverter button would not operate anything but tv and drained batteries, and the voltage meter pegged in the high end.
Checked the inverter charger and three buttons of sorts actually two and a third with maybe a cap missing, was protruding a quarter inch or so. Pushed it down and fan on inverter converter kicked in and the circuits came alive, and house batteries were taking a charge again. Happened twice more and one time one 15 amp breaker tripped. Havne't figured out why the Inverter charger Converter was even involved and where the second circuit is as both GFCIs were located but only one breaker tripped but all ac circuits were dead unless thoe in the basement. Only other thing I can think of is one or both the batteries are wired ,wrong bad or dead.