Motorized Wheel Chair Source

The Solar constant is 1,366 watts per square meter. I have trouble envisioning metric units, so let's say you get a 4' x 8' solar panel. Ideal energy impingement of the panel would be (1366W/m^2)(32 ft^2)(2.54/100)^2(m^2/in^2)(144 in^2/ft^2) = 4,061 W when the panel is facing the sun perfectly. Even if you track the sun the power received by your panel will vary sinusoidally due to atmospheric attenuation, so the average power you get in the daytime is 0.6366*4,061 = 2,585 W. I'm unsure about the efficiency of solar panels, but I suspect it is no greater than 50%, taking you down to 1,293 W. Motor-generator inverters are capable of delivering up to 94% efficiency, but electronic inverters are limited to a maximum efficiency of 50%. Now you're down to 646 W average power, with a peak of no more than 1,015 W, or about 1 KW per panel. You need to feed the output of the solar panel(s) into a battery (bank) to store up energy for night use, dropping you to an average of 323 W per panel., or fudging a little bit, 3 A. at 110 V. That's enough to power a TV, a computer, and maybe 2 60 W lamps. Sizing the system up to be able to handle your furnace fan and refrigerator will require at least 10 panels to prevent repeated motor or compressor burnout. That's an area maybe 20 ft x 16 ft. The bank of panels or each indivudual panel must be on an equatorial mount (like a telescope) so you can track the sun not only daily, but throughout the year, although annual tracking can be dispensed with if you mount the panels ar an angle of (Latitude - 23.5). If you want to dispense with tracking altogether, multiply the number of panels by at least π/2. Remember, too, that these calculations are only good for clear days. Cloud cover can render solar panels totally ineffective.