On 22/04/2020 13:39, Jon Parker wrote:
I'm considering building a basic 12v power system for my garage comprising a car battery, a solar panel on the outside to keep it charged, and a 12v outlet on the exterior wall and probably one on the inisde also. Going to be used for running the air pump mainly when pumping up bike and car tyres, paddling pools etc.

I intend to use a 3-position switch to enable me to easily switch the battery positive to the solar charger, or over to the 12v outlets, and to prevent the outlet from receiving power when the battery is connected to the charger. I'll need some sort of weatherproof box for exterior wall outlet of course. I expect I'llneed to put a suitable fuse in the positive line, around 6 inches from the terminal, 10 or 20 amp should be fine I think.

Does that all make sense? Any suggestions?

Jon

Because you don't have mains out there? You may find you need a larger
solar panel than you might expect to keep the battery charged,
particularly in the winter. Don't expect one of the 12 inch square ones
to do much for you. DAMHIK.

I used 12 volt batteries to provide lighting to an off-grid stables, and
also run electric fencers when required. Have one of those little 12
volt LED voltmeters plumbed into the system (on a switch) so that it is
easy to keep an eye on the battery state of charge.