Off topic a little bit, but my son hikes and camps a lot and wanted this for Christmas:
https://www.amazon.com/Nekteck-Charger-Waterproof-Portable-High-Efficiency/dp/B017GQ7OEA?creativeASIN=B017GQ7OEA&linkCode=w61&imprToken=b3zF9vphZ4a1AH5DTs-fww&slotNum=6&tag=hiking043-20
He will use it to get his small GPS loaded with maps charged. Phone as well.
I could't believe how relatively cheap it is!