In some embodiments, a power supply system includes two power modules each configured to be electrically coupled to a set of battery cells. The set of battery cells produces a first voltage when in a first operational state, and a second voltage when in a second operational state. The second voltage is less than the first voltage. The first power module is configured to provide a third voltage to a load device that is substantially equal to the first voltage, when the set of battery cells is in the first operational state. The second power module is configured to provide a fourth voltage to the load device that is substantially equal to the first voltage, when the set of battery cells is in the second operational state.