A battery power supply to power an intermittently operating load includes a voltage downconverter configured to be serially connected to a battery and to output a voltage VOUT smaller than a battery voltage V1. A current limiter is serially connected to the voltage downconverter and is configured to provide a voltage drop in a current limiting mode, and to substantially provide a short circuit in a non-current limiting mode. The battery power supply additionally includes a capacitor tank serially connected to the current limiter for providing a voltage V2 to the load, and configured to be charged to a voltage VCT which is less than VOUT when the current limiter is switched to the current limiting mode. The capacitor tank is additionally configured to be charged to a voltage which is substantially equal to VOUT when the current limiter is switched to the non-current limiting mode.