The Nitecore NB20000 Power Bank GEN3 combines 20,000mAh capacity with a 291g carbon-composite body and USB-C charging with PD fast charging up to 22.5W. IPX5 protection covers everyday rain and splashing, and the airline-approved construction means it can go in carry-on luggage without issue.
The high capacity suits ultralight trekkers and photo tourists who need to charge multiple devices at once — phone, GPS unit, or mirrorless camera — without carrying several smaller banks. The downside compared to newer models is the lack of a battery-level display; all you get is a 4-LED indicator, which gives only a rough sense of remaining capacity.
For multi-day treks with no access to power, the NB20000 Power Bank GEN3 offers a solid capacity-to-weight ratio, though tracking exact charge level means relying on the connected device instead.