An approach is being pursued for a series hybrid electric vehicle (SHEV). The twin goals of maximizing Fuel Economy (FE) and improving consumer acceptance has led to a SHEV powertrain using energy storage as a means for filtering drive cycle power demands on the engine, rather than an energy source for supplying all-electric mode. The concept is intended to minimize, if not eliminate, the battery in the SHEV without resorting to full range proportional control of the engine and generator. An initial optimization study reported for a mid-size SHEV showed a 4.5 kWh Li-ion battery pack was still required.In a new research, a sports car class SHEV was studied, which inspires this manuscript. The challenge with this vehicle is to reduce the ESS size even more because the available space allocation is only one fourth of the battery size in the mid-size. In this manuscript, a controller is developed that allows a hybridized SHEV to be realized with a light ESS. The controller includes a duty cycling feature that manages the engine performance in multiple efficient regions and a bandwidth limited- proportional controller feature that limits low bandwidth battery current.The performance of the controller has been validated for a SHEV power-train model with a, 80 VDC 1.125 kWh battery, plus an 80 VDC 46.4 Farad Ultra capacitor module using customized Autonomie vehicle model. The preliminary results show that the combined FE of the new design is increased by 13 percent comparing to the corresponding FE in the equivalent conventional vehicle.