mono vs poly real life testing

12thgenusa wrote:
Third, the half-shaded panel either horizontal or vertical is a non-issue. In all cases the output is less than or equal to one amp. Who cares? None of them in those conditions will make a difference to your battery bank at the end of the day.

Yet the output from the poly panels was greater than from the mono panels by about 20% when vertically covered and 16% when horizontally covered. Going with 16%, here are some extrapolations.

You mention less than one amp--but now lets multiply by 5 hours. Assuming a 400 watt install, the return to the battery bank is now for mono about 15.6 amp-hours and for poly about 18.75 amp-hours. It is enough to keep the bank from self discharging in storage, and would meet 50% of the parasitic loads of camping for a day in my (rather hungry) RV. The poly wins by about 3 amp-hours.

The haze test showed increased output by about 1/5 more for the poly panels, so I have to disagree with your statement about there is not much of a difference.

I suspect that if it had been a totally clear day, that the poly would out perform the mono in real life, as opposed to laboratory measurements.

As to longevity, my panels are from 2005 and still, in a flat install, output 17 amps (if the battery bank is hungry). The full output is rated at 256 watts in laboratory conditions (approximately 20 amps @ 12.8 volts).

I agree the testing is "back of an envelope" quality--and that he should have included a clear day as well as clouds traveling moving over the panels to show lens effects.

Even with these quibbles, poly is usually cheaper, and often gives more of a solar harvest. So, providing there is room, I believe poly is the way to go.