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
The practical value of Voc and Isc is that you can measure them with the panel disconnected and that should tell you how things will go once you connect up. With PWM, whatever the amps you got as Isc, you should now get that connected. It is Voc that doesn't matter in that case.
The OP question is how can you do a similar thing with MPPT? If you measure Voc and it is lower than rated, does than mean the controller will not be able to find Vmp but only some lower number even if you got rated Isc ok?
I want a way with MPPT to tell I am getting the best amps possible at the time, same as I can now with PWM.
With MPPT the amps you are seeing are not related to Isc but are from the controller. You can't compare 'with controller' vs 'no controller' (panel -direct) amps unless it is a 12v panel. With a 24v panel your panel- direct amps could be the same as Isc but you could get way more than that with the controller, even if the controller were failing to provide what you should be getting. (Such as if you had a wiring or connection issue that needs fixing.)
How do you tell what you should be getting so you can see if you are getting it?
The OP question is how can you do a similar thing with MPPT? If you measure Voc and it is lower than rated, does than mean the controller will not be able to find Vmp but only some lower number even if you got rated Isc ok?
I want a way with MPPT to tell I am getting the best amps possible at the time, same as I can now with PWM.
With MPPT the amps you are seeing are not related to Isc but are from the controller. You can't compare 'with controller' vs 'no controller' (panel -direct) amps unless it is a 12v panel. With a 24v panel your panel- direct amps could be the same as Isc but you could get way more than that with the controller, even if the controller were failing to provide what you should be getting. (Such as if you had a wiring or connection issue that needs fixing.)
How do you tell what you should be getting so you can see if you are getting it?
