The design of the optimal power distribution system (PDS or powertrain) for fuel cell-based vehicles is a complex task due to PDS comprising one or more power converters, several types of secondary energy sources, a fuel cell, several control loops, and protections, among others. The optimized powertrain design tries to minimize the mass, volume, and cost, and also to improve system efficiency, fuel economy (both hydrogen and electricity), and vehicle autonomy. This paper analyzes the influence of four different factors that deeply affect the optimal powertrain design, in particular: the minimum power delivered by the fuel cell, the storage of the recovered energy from the regenerative braking periods, the battery technology, and the maximu...