Jump to Power Bank - A power bank is a portable device that can supply power from its built-in batteries through a USB port. They usually recharge with USB power supply. Technically, a power back consists of rechargeable Lithium-ion or Lithium-Polymer batteries installed in a protective casing. Empty phone or tablet battery is probably one of the situations that most frustrate every user. With power bank (universal charger) charging mobile phones on the move is no longer impossible. It is ideal for people who often travel or for users who are often out of the power supply network. It contains high-quality cells that allow storage of large capacity in a small space. It serves as a backup power supply and is compatible with all devices.