Faced with key obstacles, such as the short driving range, long charging time, and limited volume allowance of battery-powered electric light scooters in Asian cities, the aim of this study is to present a passive fuel cell/battery hybrid system without DC-DC to ensure a compact volume and low cost. A novel topology structure of the passive fuel cell/battery power system for the electric light scooter is proposed, and the passive power system runs only on hydrogen. The power performance and efficiency of the passive power system are evaluated by a self-developed test bench before installation into the scooters. The results of this study reveal that the characteristics of stable power output, quick response, and the average efficiency are as high as 88% during the Shanghainese urban driving cycle and 89.5% during the Chinese standard driving cycle. The results present the possibility that this passive fuel cell/battery hybrid powertrain system without DC-DC is practical for commercial scooters.