Depending on how much you drive a day, a propane powered generator pack for a few thousand bucks (chinesium ones start at ~1000 $ [1]) in your shed should be enough to charge during the night and keep your home powered as well, and unlike gas/diesel, propane doesn't go bad during storage.
Because you'll only need the grid backup like, what, a week or two in the worst case every two or three years? A LPG-powered vehicle will incur all the typical ICE vehicle costs during these three years.
