Artem Akulov

Hello, According to PVsyst's model, the highest value of PV module's open circuit voltage is at -10 C. When I choose temperature for example -20 C this voltage is lover than at -10C. According to the inverters manufacturers design tools (SMA or ABB) this voltage continues to rise with the lower temperature. I design PV systems in Ukraine, where winter temperature can drop to -20 C. I'm confusing. Which data I need to use when defining the number of modules in string?