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
Salvo wrote:
Careful when making a mppt to pwm comparison. Not only is mppt highly temperature dependent, but also battery voltage dependent. PWM can also be effected, but not as extreme.
For example, you got a mppt controller that outputs 100W. If battery voltage is 12.0V, charging current is:
I = P / V = 100W / 12.0V = 8.33A
If battery voltage rises to 14.0V, charging current is 7.14A, a 14.3% reduction.
Sal
OTH, assuming no losses from panel output to controller output, a 100W panel through a PWM controller will give you less than 6A all the time, 16% less than the MPPT at 14V and 28% less at 12 volts.
