Hence, the total current in a string of solar cells is equal to the smallest current generated by one single solar cell. If we connect two solar cells in series, the voltages add up. . Maximum Power Voltage (Vmp): The voltage at which the panel operates to deliver maximum power. Short-Circuit Current (Isc): The current flowing when the panel's terminals are directly connected. Too many modules on a string will exceed the maximum input voltage and damage the inverter or, worse, start a fire. The. . A solar system's capacity — whether 3 kW, 5 kW, or 50 kW — doesn't tell the full story. I often compare this process to a word scramble. Together one string will provide 819.