A system for allocating load power drawn from a battery system for powering propulsion of a vehicle, the system comprising: a high-energy battery that is designed for optimal production of DC power during high-specific-energy propulsion; a high-energy battery health management system that is configured to monitor a state of charge and a state of health of the high-energy battery and generate first battery status signals representing the state of charge and state of health of the high-energy battery; a high-power battery that is designed for optimal production of DC power during high-specific-power propulsion; a high-power battery health management system that is configured to monitor a state of charge and a state of health of the high-power battery and generate second battery status signals representing the state of charge and state of health of the high-power battery; a propulsion load (26a, 26b) configured to produce propulsion force using power converted from power generated by at least one of the high-energy and high-power batteries; and a system controller that is configured to receive the first and second battery status signals and then allocate load power drawn from the high-energy and high-power batteries for use by the propulsion load in dependence on a propulsion phase of the vehicle and the status of the high-energy and high-power batteries as represented by the first and second battery status signals, wherein the system controller is further configured to deactivate and isolate the high-energy battery and allocate a load power at a reduced power scale to be drawn from the high-power battery in response to first battery status signals indicating a fault condition in the high-energy battery. a high-energy battery that is designed for optimal production of DC power during high-specific-energy propulsion; a high-energy battery health management system that is configured to monitor a state of charge and a state of health of the high-energy battery and generate first battery status signals representing the state of charge and state of health of the high-energy battery; a high-power battery that is designed for optimal production of DC power during high-specific-power propulsion; a high-power battery health management system that is configured to monitor a state of charge and a state of health of the high-power battery and generate second battery status signals representing the state of charge and state of health of the high-power battery; a propulsion load (26a, 26b) configured to produce propulsion force using power converted from power generated by at least one of the high-energy and high-power batteries; and a system controller that is configured to receive the first and second battery status signals and then allocate load power drawn from the high-energy and high-power batteries for use by the propulsion load in dependence on a propulsion phase of the vehicle and the status of the high-energy and high-power batteries as represented by the first and second battery status signals, wherein the system controller is further configured to deactivate and isolate the high-energy battery and allocate a load power at a reduced power scale to be drawn from the high-power battery in response to first battery status signals indicating a fault condition in the high-energy battery.