If you need an external battery to help you when your mobile phone has run out of power, a 1,000mAh or 2,200mAh Powerbank may be sufficient to extend the operating time of your mobile phone as much as necessary. With a 4,000 or 5,000mAh powerbank you can fully charge the battery of a modern mobile phone, and thanks to the larger capacity 10,000mAh powerbanks, you can fully charge the battery of a tablet or even two mobile phones simultaneously.