Use 24v Batteries to run 12v System... Possible?

Boon Docker, the problem with offgrid camping in Ca is that winter there is better than summer :) - nice weather, not too hot.

However, very low sun, panels harvest much less than in summer. In some places it gets cloudy too. In the night it can get cold enough to need a furnace, this is additional energy draw. IMO, flat 500W is just about the minimum, if they want to avoid generator run.