What is Power Bank?
Power bank serve as an â€˜extra battery' or external charger for your phone or other electronic devices. It is a portable power source built of rechargeable battery, packed in a small case that can be carried in a handbag or purse. It has at least one input for charging and another recharging port that can be connected to a standard USB cable that can recharge portable electronic devices like smartphones, media players and tablet PCs.
Most of the newest power-bank models, arrive with built-in Lithium polymer battery, which known by high efficiency and long lifetime. The capacity of power packs is measured by mAh and can reach 20,000 to 30,000mAh.