A portable power and/or memory device is disclosed, which device includes integrated management circuitry enabling on-board management of energy storage, power management, and memory management. In a preferred embodiment, the device of the present invention can store and make available both memory and power, and provides an on-board means for displaying the various memory and/or power parameters associated with the device, using a USB interface to receive power for storage and to communicate between onboard memory and a device to which the portable power and/or memory device is connected.