Solar Illuminace vs Panel Output
How does solar illuminace effect panel output? From yesterdays observation at noonish: 750W, poly, flat, 100F ambient, Vmp=91.7V, Imp=8.18 Logged Varray=75V, Iarray=8.5A, Controller out=605W ...
Forum Discussion
Sure but what does Voc have to do with the MPPT operation which uses Vmp?
Another panel spec is Isc and what does this have to do with a MPPT controller that uses Imp?
It’s just not apparent how you can use panel specs and temp coefficients to get a reasonable idea of what to expect with MPPT. Perhaps the bottom line is the controller output. For my flat panels at noonish I was getting 44A and 605W from my flat 750W panels at 100F ambient and perhaps 131F panel cell temps.
OK, heat reduces the output but by how much? At 131F my panel specs say I should get 658W and I got 605W, so perhaps 53W was loss due to flat mounted? But my panels are mounted 6” off of the roof so perhaps the panel cell temp is below 131F which is just a guess anyway.
We all use generalized panel information which is what we’ve got and what I used as a basis for my system. But having a quality controller that logs data under live operating conditions is proving enlightening.
Another panel spec is Isc and what does this have to do with a MPPT controller that uses Imp?
It’s just not apparent how you can use panel specs and temp coefficients to get a reasonable idea of what to expect with MPPT. Perhaps the bottom line is the controller output. For my flat panels at noonish I was getting 44A and 605W from my flat 750W panels at 100F ambient and perhaps 131F panel cell temps.
OK, heat reduces the output but by how much? At 131F my panel specs say I should get 658W and I got 605W, so perhaps 53W was loss due to flat mounted? But my panels are mounted 6” off of the roof so perhaps the panel cell temp is below 131F which is just a guess anyway.
We all use generalized panel information which is what we’ve got and what I used as a basis for my system. But having a quality controller that logs data under live operating conditions is proving enlightening.
