How many Solar Panels for a 100w Compressor?

Yeah, what KiwiBuzz said. For UK allow for 10x the power as a starting point 100W x 10 = 1kW, as that will do it for cloudy days. Then factor in winter daylight is like 40% of the time, so divide by 0.4 gives 2500W, then double it for charging losses, really long spells of carp weather, and you get 5kW. Typical large panels these days are 400W so you'll need 12 or so. Roughly. Probably. For storage you want lithium as lead-acid you can only run to 30 or 40% discharge, and you want enough storage to cover long spells of winter cloudy weather so enough to run for 4 days continuous which is 100W x 24 x 4 / 80% = 12kWh. Probably.

Yeah, what KiwiBuzz said. For UK allow for 10x the power as a starting point 100W x 10 = 1kW, as that will do it for cloudy days. Then factor in winter daylight is like 40% of the time, so divide by 0.4 gives 2500W, then double it for charging losses, really long spells of carp weather, and you get 5kW. Typical large panels these days are 400W so you'll need 12 or so. Roughly. Probably. For storage you want lithium as lead-acid you can only run to 30 or 40% discharge, and you want enough storage to cover long spells of winter cloudy weather so enough to run for 4 days continuous which is 100W x 24 x 4 / 80% = 12kWh. Probably.