I have used other external batteries by Anker, but I wanted the best one they make, so I just received this one today. It has enough power to recharge my phone LOTS of times. http://www.amazon.com/Anker-Ultra-High-Capacity-25600mAh-Technology/dp/B00M3073L4/ref=sr_1_1?ie=UTF8&qid=1439777968&sr=8-1&keywords=anker+e7
That’s a beast - a little excessive for a smartphone no?
Depends on how long of a trip. Could bring it camping too.