Panel to Solar Controller Wire Size
As some of you already know, I'm piecing together a solar system. Controller is a Morningstar 45A PWM. Panels will be two 12V 150W wired in parallel. I'm going to be using a combiner box on the roof, ...
Forum Discussion
Hi BFL13,
You won't get much charging where the voltage on a 17 volt panel that heat has dropped to 13.6
Whereas my system is nominally 33 Volts--so I can laugh at even a 30% reduction in voltage. 33 x .7 = 23.1
That would be, with standard panels, a surface temperature of 85 c (185 f). Unisolars do a little better with heat "fatigue", I think partly because there is a much lower thermal mass because of the lack of glass.
You won't get much charging where the voltage on a 17 volt panel that heat has dropped to 13.6
Whereas my system is nominally 33 Volts--so I can laugh at even a 30% reduction in voltage. 33 x .7 = 23.1
That would be, with standard panels, a surface temperature of 85 c (185 f). Unisolars do a little better with heat "fatigue", I think partly because there is a much lower thermal mass because of the lack of glass.
BFL13 wrote:
PT, usually the story is that the panel heating hurts MPPT more from the voltage drop whereas PWM doesn't care much about voltage drop and anyway, Isc goes up with heat. MPPT doesn't care about Isc, it uses voltage.
