Heat 1, MPPT 0
Previously we noted that heat is hard on MPPT due to the panel's loss of voltage with increasing heat. Doesn't bother PWM though, you still get Isc or more. This Spring, I took some measurements p...
Forum Discussion
12thgenusa wrote:
Refresh my memory. How are you obtaining the PWM amperage for comparison on the 24-volt panel.
I discovered with my various wattage 12v panels that they have Isc in proportion to the wattage (except some with extra high Voc which then have lower than usual Isc) So my 80w got 5a, the 130 got 8.2 and the 120 got 7.6.
So it works out that 230w worth of 12v panels would get 230/130 x 8.2= 14.5amps I was getting 15.5 with the 230 and MPPT so that was the comparison. Now I am getting a bit less than the 14.5 I would be getting if I had two 115w panels and PWM.
Only thing that has changed is the ambient temperature. The under-panel temp has not changed much with the rise in ambient.
The wattage as reported on the controller readout, matches the amps as seen on the Trimetric and the controller times the battery voltage. Now the wattage is consistently lower than before and so are the amps.
