Google Project Sunroof can give a general idea of how many hours of good sunlight a given roof-mounted solar setup will receive.
check timeanddate.com's Sunrise and Sunset Calculator for day length on the following days:
solar panel's rated power output | W | P |
---|---|---|
hours of usable sunlight per year | hr | Syr |
average hours of usable sunlight per day | 5.475851494907458 hr | Sd = Syr / 365.25 |
longest day length | hr | Dl |
shortest day length | hr | Ds |
average day length | 12.25 hr | Da = avg(Dl, Ds) |
average solar effeciency guess-timate[0] | 45 % | E = Sd / Da |
longest day solar power output[1] | 2593 Whr | = P * E * Dl |
shortest day solar power output[1] | 1788 Whr | = P * E * Ds |