Everyone,
when calculating the input voltage from the solar panels, do you use open circuit voltage or VMP, or voltage at load?
The panels I'm interested in list open circuit voltage at 49.8V while voltage at load is 40.3V. When you add 12 panels in series, there's quite a bit a variance between the two, like 114V difference.
So which one do you use to calculate input voltage for the controller?
Mike
Open Circuit Voltage, corrected for the coldest temperature experienced in your area. The best sure way to destroy a Charge Controller is supplying too much voltage. Midnite provides a voltage calculator on their website for their charge controllers. You pick your solar panels or just type in the voltages, high & low temps, # of panels and serial-parallel combinations, and it will calculate if you are within limits for the different combinations. Good luck with your system!
Dave
Quote from: aaapilot on January 05, 2026, 04:23:18 PMOpen Circuit Voltage, corrected for the coldest temperature experienced in your area. The best sure way to destroy a Charge Controller is supplying too much voltage. Midnite provides a voltage calculator on their website for their charge controllers. You pick your solar panels or just type in the voltages, high & low temps, # of panels and serial-parallel combinations, and it will calculate if you are within limits for the different combinations. Good luck with your system!
Dave
I knew about the calculator, and thought it was for the classic only as the Hawk's Bay has a much higher input voltage. I'll check it out.
mike