Today most of the new Smartphone released into the market are backed by big batteries ranging from 3500 to 4500 mAh. By keeping these requirements in mind, it is a good idea to buy high capacity power banks for Smartphone ranging from 10000 to 20000 mAh. Power banks with this capability can quickly charge your mobile up to 4 to 6 times. Portronics POR 695 Wallet 10 is a great fit. It is a 10000mAh mega power bank, yet compact and sleek.