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
another update and a few more experiments to do before posting.
First, there was a question of how shade affects panels connected in series with a MPPT controller, so today I'm going to hook the panels up again and put one in full shade to see the effect. I think battery charging current will basically drop in half.
Second, BFL asked about measuring Voc and/or Isc to find optimal panel positioning. I've done that. It works (at least when I tried it)
Now with the panels hooked up and connected to an MPPT controller I'm going to see if I can find optimal angle by measuring the current to the controller. Once hooked up I can't easily measure Vpanel, but I can easily measure current with my clamp on dc current probe. However, a MPPT controller doesn't continually search for max power, it does it periodically, so i don't know how well looking at panel current will do for finding optimal angle once under power.
First, there was a question of how shade affects panels connected in series with a MPPT controller, so today I'm going to hook the panels up again and put one in full shade to see the effect. I think battery charging current will basically drop in half.
Second, BFL asked about measuring Voc and/or Isc to find optimal panel positioning. I've done that. It works (at least when I tried it)
Now with the panels hooked up and connected to an MPPT controller I'm going to see if I can find optimal angle by measuring the current to the controller. Once hooked up I can't easily measure Vpanel, but I can easily measure current with my clamp on dc current probe. However, a MPPT controller doesn't continually search for max power, it does it periodically, so i don't know how well looking at panel current will do for finding optimal angle once under power.
