One of the most frustrating ‘first-world’ problems is a dead cellphone battery. Here is a fix: Set up your own makeshift charger with a 9-volt battery. The best part is that it does not damage your phone. All you need is a little know-how and it could help you stay away from quite a lot of hassle. 
The items required for this DIY trick are as follows; a car charger, a piece of metal (key for this instance) and a 9-volt battery. As shown in the video, the charger can be simply created by fixing the metal piece to the metal piece located on the car charger and then fixing the other end of the metal piece to the negative terminal of the battery and creating contact of the metal end from the car charger to the positive battery terminal. 
Do let us know how this trick worked out for you!
Patético
Check this,No need to buy a Power bank ,you can use your smartphone charger to charge your device without using a power supply. Please send your suggestion &@like @
www.fb.com/hybridsmartcharger