Voc with temperature lower than -10C

[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?

[Lazare Fesnien]

Hi,

You need to change the value below:

Absolute Cell lower temperature for determining the Maximum possible voltage of the array. The default is set to -10°C for most European countries (best practice rule).

For this limit, the cell temperature is considered as the ambient temperature (worst case when the sun suddenly appears on the field).

You should define the lowest temperature ever observed during the day for this site.