Kentli makes the best rechargeable lithium-ion AA batteries currently available. They are rated at 2800mWh, and are the only 1.5 V li-on AA batteries, making them the best choice for consumer-grade electronics.
The best pre-charged rechargeable AA batteries of 2016 are Panasonic’s Eneloop Pro AA Batteries. They are made with Nickel-Metal Hydride (NiMH) chemistry and have low standard discharge, meaning they can hold a charge for years.
The best waterproof portable charger is the Unifun Waterproof External Battery. This charger has enough capacity to charge an iPhone 6 about 4 times. It has two USB ports to charge two devices simultaneously. One port has a higher amperage for charging tablets.