Solar Energy

here comes the sun, solar energy and what it can do for you



A typical crystalline solar cell produces an output voltage of 0.5V with a current output of approximately 7A per 6sq. in.. A module is composed of 30 to 36 cells connected in series to produce a nominal output voltage of 12V (17V peak), modules can then be wired in series to produce higher voltages. The irradiance of our sun, the power availiable at the surface of the earth, averages approximately 1000 Watts/sq. meter in full sun. Our typical modern crystalline solar cells only reproduce 14% to 16% of this energy (140W to 160W). The length of "full sun" period in the US varies from 4 hours in the northern states to 6.5 hours in the southern states, irradiance diminishes outside this time window. Since solar panels produce DC current (flatline, non-sinusoidal waveform), DC appliances are a great compliment to such a system, however, they are currently hard to come by. Therefore, additional hardware such as an inverter (DC to AC) is required to power typical AC appliances.


Solar Panels And Their Ratings

Solar panels are rated for maximum current (Isc) and voltage (Voc) output and average current (Ipm) and voltage (Vpm) output. The power output (Watts or W) is derived from the average ratings (current x voltage).
Some popular recently produced solar panels are:
Sharp 24V 180W, average cost $800
Voc=44.6V
Vpm=35.86V
Isc=5.6A
Ipm=5.02A
Max Sys Voltage= 600VDC

Kyocera 12v 125W, average cost $700
Isc=8A
Voc=21.7V
Vpm=17.4V
Ipm=7.20A
Max Sys Voltage 1000V

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