Abstract: A hybrid electrical power system for an electric vehicle, particularly an industrial electric vehicle such as an electric forklift, comprises a fuel cell stack, a DC/DC converter and a Li-ion battery. The DC/DC converter comprises a transformer for converting a voltage of direct current generated by the fuel cell stack to another voltage, and a controller for generating a reference voltage for the another voltage to approach. When the reference voltage is set to be larger than the another voltage, the fuel cell stack provides power to drive the vehicle and charge the Li-ion battery. When the reference voltage is set to be not larger than the voltage of direct current from the Li-ion battery, both the Li-ion battery and the fuel cell stack provide power to drive the vehicle.