In a scenario where the cold module temperature is 40C and the inverter's maximum input is 110V, what is the maximum number of PV modules that can be connected in series?

To determine the maximum number of PV modules that can be connected in series, it's important to consider the temperature coefficient of the PV modules along with their open-circuit voltage (Voc) ratings at standard test conditions (STC). Typically, the Voc of PV modules increases with a decrease in temperature, which means that at colder temperatures, the module can produce a higher voltage than rated.

At a standard temperature of 25°C, a typical solar module might have a Voc around 30V to 40V. However, when the temperature drops to 40°C, the output also decreases. It's crucial to use the temperature coefficient of voltage, which is usually around -0.3%/°C for many silicon-based PV modules.

In this case, if we consider a module that has a Voc of, say, 36V at 25°C, at 40°C (which is a 15°C rise), the Voc can be calculated as: Voc at 40°C = Voc at 25°C + (Voc temperature coefficient x 15°C) Assuming a temperature coefficient of -0.3% per degree C, this would reduce the voltage by approximately 4.5%: Voc at 40°C ≈