Quote:
Originally Posted by Casey Freswick
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If they can be made to fit on the roof, 200w panels always weigh less than two 100w panels built with the same glass, because the wattage (area) grows faster than the circumference (The length of heavy aluminum framing). The weight of the junction box and extension cables is virtually unchanged.
9BB cells are the current state of the art for lower-powered panels. These panels would be an excellent choice, but they should be wired in series with an MPPT Solar Charge controller, at much HIGHER Solar Charge Controller cost than a cheap but power-wasting PWM-type SCC.
If used with a PWM, they would have to be wired in parallel. High current (up to 10.76A each under 'nearly perfect, very bright' sunlight conditions, 21.5A total) would require that the solar cables down the shell and lift arms (into the TM and solar controller) be more expensive 10-AWG, rather than the usual 12-AWG. 12-AWG is not rated for more than 20A maximum. And of course, your PWM controller would refuse to accept about 25% of the power from the panels.
Correctly wired in Series for an MPPT controller, two panels together would run at 18.6 * 2 = 37.2 volts, with a maximum voltage of 21.8 * 2 = 43.6 volts. That is easy for a "100 volt" MPPT controller to handle. In series, the CURRENT from the pair is only the smaller of the two panels - if both are under great sunlight, that's 10.76 Amps.
10.76 amps is an easy load an 12-AWG solar wires, and 14-AWG solar wires would also be OK.