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 ...
If you're worried about it then pull the negative battery lead or install a disconnect switch. Modern converters with "smart" charging can be left plugged in continuously. Older ones (Magnetek & Elixir come to mind) were "dumb" single stage converters and could boil the batteries.