In the past few years, we have covered plenty of power banks for smartphones and tablets. The Bixpy PP-166 Power Bank is designed to withstand unfavorable conditions. It can withstand exposure to the rain, sand, sunlight, and mud. It is submersible to 30ft and can charge your tablet and smartphone up to 8 and 30 times respectively.
This power bank has lithium iron phosphate (LiFepO4) cells in a rugged case. It has 166Wh capacity, so you can run a small fridge, LED lantern, or fan on this. Expected to ship in October. You can find this project on Indiegogo.