A multi-source energy storage system,, comprising: a first energy storage system configured to be coupled to an electrical load; a first DC/DC converter configured to be coupled between the first energy storage system and the electrical load; a first switch device connected between the first energy storage system and the first DC/DC converter; a second energy storage system; a second DC/DC converter coupled to the second energy storage system, and the first DC/DC converter, and configured to be coupled to the electrical load; a second switch device connected between the second energy storage system and the second DC/DC converter; a bypass configured to be coupled between the first energy storage system and the electrical load so as to bypass the first DC/DC converter, wherein the bypass includes a third switch device; and a controller configured to control the first and second energy storage systems (210, 220) and the second DC/DC converter so as to operate the multi-source energy storage system in: a precharge mode, in which the first energy storage system is configured to charge the second energy storage system via the second DC/DC converter, and in which the first switch device is open and the second and third switch devices (224, 234) are closed so that the first energy storage system is configured to be coupled to the second DC/DC converter and the electrical load via the bypass;and a normal mode, in which the first and second switch devices (214, 224) are closed and the third switch device is open so that the first and second energy storage systems (210, 220) are configured to be coupled to the electrical load via the first and second DC/DC converters (212, 222), respectively; in which, when either the second energy storage system, the first DC/DC converter or the second DC/DC converter malfunctions, the controller is configured to control the multi-source energy storage system so that the first and second switch devices (214, 224) are open and the third switch device is closed and the first energy storage system is configured to supply power to the electrical load via the bypass and the second energy storage system is configured to be decoupled from the electrical load. a first energy storage system configured to be coupled to an electrical load; a first DC/DC converter configured to be coupled between the first energy storage system and the electrical load; a first switch device connected between the first energy storage system and the first DC/DC converter; a second energy storage system; a second DC/DC converter coupled to the second energy storage system, and the first DC/DC converter, and configured to be coupled to the electrical load; a second switch device connected between the second energy storage system and the second DC/DC converter; a bypass configured to be coupled between the first energy storage system and the electrical load so as to bypass the first DC/DC converter, wherein the bypass includes a third switch device; and a controller configured to control the first and second energy storage systems (210, 220) and the second DC/DC converter so as to operate the multi-source energy storage system in: a precharge mode, in which the first energy storage system is configured to charge the second energy storage system via the second DC/DC converter, and in which the first switch device is open and the second and third switch devices (224, 234) are closed so that the first energy storage system is configured to be coupled to the second DC/DC converter and the electrical load via the bypass;and a normal mode, in which the first and second switch devices (214, 224) are closed and the third switch device is open so that the first and second energy storage systems (210, 220) are configured to be coupled to the electrical load via the first and second DC/DC converters (212, 222), respectively; in which, when either the second energy storage system, the first DC/DC converter or the second DC/DC converter malfunctions, the controller is configured to control the multi-source energy storage system so that the first and second switch devices (214, 224) are open and the third switch device is closed and the first energy storage system is configured to supply power to the electrical load via the bypass and the second energy storage system is configured to be decoupled from the electrical load. a precharge mode, in which the first energy storage system is configured to charge the second energy storage system via the second DC/DC converter, and in which the first switch device is open and the second and third switch devices (224, 234) are closed so that the first energy storage system is configured to be coupled to the second DC/DC converter and the electrical load via the bypass;and a normal mode, in which the first and second switch devices (214, 224) are closed and the third switch device is open so that the first and second energy storage systems (210, 220) are configured to be coupled to the electrical load via the first and second DC/DC converters (212, 222), respectively; in which, when either the second energy storage system, the first DC/DC converter or the second DC/DC converter malfunctions, the controller is configured to control the multi-source energy storage system so that the first and second switch devices (214, 224) are open and the third switch device is closed and the first energy storage system is configured to supply power to the electrical load via the bypass and the second energy storage system is configured to be decoupled from the electrical load.