This disclosure provides systems, methods and apparatus for a combined battery/capacitor energy storage device. The device includes a first device terminal, a second device terminal, a battery connected between the first terminal and the second terminal, and a capacitor connected in parallel with the battery. In one aspect, a rectifier is connected between the first terminal and the capacitor, the rectifier configured to allow substantially unidirectional current flow from the first terminal to the capacitor. In another aspect, a switch is between the capacitor and the first terminal. In another aspect, a current limiter extends between the first terminal and the capacitor.