From: http://blog.vincentlaforet.com/2015/11/26/the-2015-holiday-gear-guide/

Sanho P18 Hyperjuice 1800mAh Dual USB Battery

There were a few instances this year when we were out in remote locations where the HyperJuice was absolutely essential. Every one of us should have the ability to power our devices anywhere, and these seem to provide the best bang for buck I’ve found. The dual USB ports are also great to share charging with a friend or to power 2 devices off of the same unit.  I actually often go to hotels overseas where I am either too tired to find the proper power adapter and I’ll charge two phones, or a phone and iPad for several nights with this unit. If you go outdoors for time lapse and/or are camping this is the big secret out there. This HyperJuice lives in my Tenba backpack 24/7 – literally.