TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The battery pack optimization system further comprises: a system controller (115), where the system controller configured to open at least a first valve controlling oxygen-rich effluent flow from the battery pack air outlet to the compressor and the tank inlet during a battery pack charge cycle, and configured to open at least a second valve controlling oxygen-rich effluent flow from the tank outlet to the battery pack air inlet during a battery pack discharge cycle; at least one pressure monitor coupled to the system controller, which is configured to initiate operation of the compressor during the battery pack charge cycle when the pressure monitor indicates a pressure in excess of a preset pressure; at least one battery pack pressure monitor coupled to the system controller, which is configured to maintain battery pack pressure within a preset pressure range; at least one battery pack oxygen monitor coupled to the system controller, which is configured to modulate flow of oxygen-rich effluent from the tank outlet to the battery pack air inlet during the battery pack discharge cycle to maintain battery pack oxygen levels within a preset oxygen range; a heat exchanger interposed between the battery pack outlet and the compressor; and a battery pack charger circuit, where the compressor receives power from the battery pack charger circuit. The system controller configured to: initiate operation of the compressor during the battery pack charge cycle; close the first valve controlling oxygen-rich effluent flow from the battery pack air outlet to the compressor and the tank inlet during the battery pack discharge cycle, and configured to close the second valve controlling oxygen-rich effluent flow from the tank outlet to the battery pack air inlet during the battery pack charge cycle; open a third valve controlling air flow from an ambient environment to the battery pack air inlet during the battery pack charge cycle, where the third valve is coupled to a one way valve, which allows air flow into the battery pack inlet; or open a third valve controlling air flow from the tank outlet to the ambient environment during the battery pack discharge cycle, where the third valve is coupled to a one way valve, which allows air flow out of the battery pack outlet. Preferred Method: The method further comprises: initiating operation of the compressor during the battery pack charge cycle, and terminating operation of the compressor during the battery pack discharge cycle; closing the tank outlet or inlet and the battery pack inlet or outlet during the battery pack charge cycle, and opening an ambient air battery pack inlet or outlet during the battery pack discharge cycle; selecting a one way inlet for the ambient air battery pack outlet, where the one way inlet allows ambient air to pass into the metal air battery pack during the battery pack charge cycle and does not allow the oxygen-rich effluent to pass out of the one way inlet; monitoring pressure within the metal-air battery pack or at a compressor inlet, comparing the pressure to a preset pressure level, and initiating operation of the compressor during the battery pack charge cycle when the pressure is above the preset pressure level and terminating operation of the compressor during the battery pack charge cycle when the pressure is below the preset pressure level; monitoring oxygen levels within the metal-air battery pack, comparing the oxygen levels to a preset oxygen range, and modulating flow of the oxygen-rich effluent from the tank outlet to the battery pack inlet during the battery pack discharge cycle to maintain the oxygen level to within the preset oxygen range; passing the oxygen-rich effluent through a heat exchanger, the heat exchanger located between the battery pack outlet and the compressor; and withdrawing heat from the oxygen-rich effluent utilizing the heat exchanger during at least a portion of the battery pack charge cycle.