Temperature coefficient

A temperature coefficient is a datasheet value that shows how a PV module's electrical rating changes for each degree Celsius change in module or cell temperature from a stated reference condition. For solar modules, the power and open-circuit voltage coefficients are usually negative, so hot cells tend to reduce output and cold conditions can raise voltage. It appears beside Pmax, Voc and Isc on module datasheets and can affect performance estimates, string-voltage checks and inverter input-limit calculations. The coefficient is not the same as module efficiency, degradation, STC, NMOT, annual yield, export capacity, DNO acceptance, warranty entitlement or installation quality.