A propulsion system comprising an electric drive, a DC link electrically coupled to the electric drive, and a first energy storage system electrically coupled to the electric drive, the first energy storage system comprising at least a high specific-power energy storage device is shown. The propulsion system further includes a second energy storage system, wherein a first terminal of the second energy storage system is electrically coupled to the electric drive through the DC link and a second terminal of the second energy storage system is coupled in series with a terminal of the high specific-power energy storage device. A multi-channel bi-directional boost converter is coupled to the first energy storage system and to the second energy storage system, wherein the connection between the terminal of the high specific-power energy storage device and the second terminal of the second energy storage system bypasses the multi-channel bi-directional boost converter.