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....
Forum Discussion
Voc is measured at I believe 25C. The panel is kept at 25C and a very short irradiance burst is applied to the panel. The open circuit voltage is immediately measured. The panel doesn't have time to heat up.
If you have solar irradiation, the panel will heat up. PV is only 17% efficient. The rest of the irradiance goes to heat (some to reflection). If you're not reading rated Voc, then it's most likely due to panel temperature rise.
Not likely, but perhaps the panel is slightly loaded when measuring Voc? Perhaps bypass diode leakage current is high?
Perhaps you don't have 1000W/m^2 irradiance when measuring Voc?
Sal
If you have solar irradiation, the panel will heat up. PV is only 17% efficient. The rest of the irradiance goes to heat (some to reflection). If you're not reading rated Voc, then it's most likely due to panel temperature rise.
Not likely, but perhaps the panel is slightly loaded when measuring Voc? Perhaps bypass diode leakage current is high?
Perhaps you don't have 1000W/m^2 irradiance when measuring Voc?
Sal
