Can someone explain please with solar panel ratings, what is the difference between open-circuit voltage and max power voltage, and also max power and max power current?
SPECIFICATION: Maximum Power(Pm): 200Wp This a nominal power rating under special test conditions. Not achieved often in the real world, you only get 70-80% of that. Open-Circuit Voltage(Voc): 21.42V The max voltage produced when not connected and no current used. Important to know for the safety of the regulator life. Short-Circuit Current(Isc): 12.22A The max current under test conditions with the leads shorted together. Not achieved in the real world. Maximum Power Voltage(Vmp): 17.5V The important voltage produced under test conditions to get max power out of the panel. Use this for comparing panels. Maximum Power Current(Imp): 11.43A The important max current produced under test conditions to get max power from the panel. Use this for comparing panels.
Standard Test Conditions: 1000W/m˛, AM1.5, 25°C These are the test conditions used for the panels. In the real world on a caravan roof these do not apply. EG The sun does not always shine as strong as that. It is not always straight above the panel. The temperature is much higher and that is bad for the power output.
Cheers Jaahn
-- Edited by Jaahn on Saturday 5th of May 2018 02:14:12 PM