The disclosed power system may comprise first and second batteries; an electrical power generator; an electrical load powered by at least one of the first battery, the second battery or the electrical power generator; a converter; and a battery management controller. The converter is connected to both the first and second batteries and configured to operate in a neutral mode, a first battery charging mode, or a second battery charging mode. The converter is configured to create a voltage difference between the first and second batteries in the charging modes. The battery management controller is configured to monitor the voltage of the first battery and the voltage of the second battery and/or to monitor current flow to and from the first and second batteries. The controller controls operation of the converter to operate in the neutral mode, the first battery charging mode or the second battery charging mode.