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
You're beginning to see the negative sides of mppt. From the get-go, mppt has about 30% advantage over pwm. But much of that advantage evaporates. The killer of mppt is heat. The PV cell voltage decreases 2 mV for every rise in degree Centigrade. A 24V panel may have 68 cells. A 10 deg C rise in panel temperature, which by the way is way less than typical, reduces panel voltage (as well as panel power) by:
V_drop = 68 cells * 10C - 2mV/C/cell = 1.36V
That's a 4% loss in voltage and output power.
Sal
V_drop = 68 cells * 10C - 2mV/C/cell = 1.36V
That's a 4% loss in voltage and output power.
Sal
BFL13 wrote:
So that makes it more difficult to do better with MPPT than with PWM? Rats.
