A power bank includes, in part, a rechargeable battery, a wireless power recovery unit adapted to receive power wirelessly, a battery charging circuit adapted to deliver the power recovered by the power recovery unit to the rechargeable battery, an output interface, and a voltage reconditioning circuit adapted to supply power from the rechargeable battery to the output interface for delivery to an external device. The wireless power recovery unit may include one or more of a multitude of photodiodes adapted to convert a coherent optical signal to electrical power, an acoustic transducer adapted to convert acoustic waves to an electrical power, an inductive coupling circuit adapted to convert time varying magnetic flux to electrical power, and an RF power recovery unit adapted to convert an RF signal to electrical power.