I have some HQST 100W panels. They are 12v, but in the specs state open circuit of 24.6v and optimum operating voltage of 20.6v and operating current of 4.85a
I'm planning on connecting 7 of these in series to a 100/50 MPPT controller. Is that correct sizing? 7x12v of 7x20v?
HI @Greg Griffin,
The PV input voltage limit for that MPPT (in your case 100V) is the absolute maximum under any conditions. So you would use the open circuit voltage (in this case 24.6V) and also take into account the temperature (PV voltage goes up when it gets colder).
So 7 in series would be too much, depending on where you live, 4 might be too much. And given there is no easily divisible for 7 panels, probably best to have 2 parallel strings of 3 panels in series.
For more precise calculations, you can use the Victron MPPT sizing calculator, that is accessible from the MPPT product page title.
