Big, external battery to power cellphone over USB?
I don't know much about the field, and would like to use my Samsung Galaxy Nexus
for week-end getaways.
Problem is, even using offline maps + routes (ie. with no cellphone connection) and just relying on GPS eats batteries.
The original came with a 3.7 Volt Li-Ion 1850mAh battery. I know there are bigger batteries, but 1) they're a bit thick, and 2) probably won't provide enough power to last a whole day.
So I was wondering if there were external, big batteries that could power the device over the USB cable for a couple of days?