Must have insurance
I have kept a boat on a mooring for three years. It had an outboard, so the only charging for the single house battery (not used for starting, just bilge pump and lighting) was the solar panel. It was small, but did made leaving the boat at the mooring for an extended period of time more worry free as I never had to pull and charge the battery during the season. I moved up to a 30 footer and have started shopping for a solar panel already. If you get a small one, you do not need a charge controller. If you will mount it on deck somewhere, make sure you get something flexible and durable. Otherwise, mount it out of the way. You don't need much of a panel if you mostly daysail, however, if you weekend on the mooring I'd opt for a bigger panel. Another neat trick, if you have shore power on your boat, is to buy a small generator and fire it up in your cockpit. Some of the hondas are pretty quiet, durable and I think a 1500w unit only weights 40 lbs or so.Bob