I live in a similar-ish situation where I live on a narrowboat in London. I have a solar panel for electrical needs and I run the boat engine once every few day

I live in a similar-ish situation where I live on a narrowboat in London. I have a solar panel for electrical needs and I run the boat engine once every few days during the winter. For refrigeration, I've got a 12v fridge but many people I know use gas fridges. Fridges use up an amazing amount of power. But the fridge is really the only thing I run off electricity - occasionally charge up my laptop and charge my phone off the 12v supply. But yes, my boat batteries are pretty much there only for the fridge.