[Nebster]

Yes, the batteries could be okay. My "2 hours" was not a scientific measurement of A/C run time either. At the moment all the interesting loads (fridge, AC) seem to be on the leg that is dead, so it's rather hard to run a real test.

But despite sufficient testing, what makes me suspect the batteries anyway is that the charge side does appear to work okay, and after coming off shore power the batteries recede from 12.9V to 12.5, 12.4V, and lower very quickly even with the pretty minimal, remaining load.