My hybrid has never been without power. I keep it plugged in on a 20A circuit 365 days a year. I was told yesterday by a motorhome owner that it was not good to do it, although he did not give me any ...
pitch, you should be fine keeping it plugged in, IF you check the batteries ever so often, in case the converter starts overcharging.
for me, i could keep mine plugged in but i chose to install a battery disconnect switch. that way i don't have to worry about the converter failing and overcharging the batteries AND it's not costing me money by keeping it plugged in.
after 4 months of storage, unplugged, the batteries were only about 15% down, using the disconnect switch.