Solar Panel Voc-MPPT?
Wondering if there is any relationship between measured Voc and MPPT performance with a 24v panel. My 12v panel has a Voc rating of 21.9 and Isc of 8.2, but I often see 8.2ish when Voc is only 20....
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I've been on the road for the last 5 weeks. Heading for New Orleans now. I don't have the time for any in depth analysis. I didn't say anything was wrong with your previous calculation. Some research on panel temperature rise would be good. I bet if you got 1000W/m^2 irradiance then there's way more than a 25C panel temp rise. The panel is only 17% efficient. The rest of the energy goes to heat.
Regarding surface charge. I think this is a big factor that hammers mppt performance. A battery is considered full when at 12.9V. Yet when charging, battery voltage gets up to 14V or more. Any voltage greater than 12.9V can be considered surface charge (plus IR drop).
Sal
Regarding surface charge. I think this is a big factor that hammers mppt performance. A battery is considered full when at 12.9V. Yet when charging, battery voltage gets up to 14V or more. Any voltage greater than 12.9V can be considered surface charge (plus IR drop).
Sal
12thgenusa wrote:Salvo wrote:
MPPT gains over pwm are in the 8% region when battery is held between 12.0 and 12.4V. What do you think the gain becomes when battery is at 13.0V?
What part of the calculations in my previous post do you dispute? You like to fixate on the reduced performance at extreme elevated temps yet reject the performance figures obtained at reasonable operating temps.
