Will Fenix (Internal USB) ARB-L18-2600U or ARB-L18-3500U fit Zebralights?
https://www.amazon.com/dp/B01N2KKJXN/?tag=cpf0b6-20
https://www.amazon.com/dp/B01N2KKJXN/?tag=cpf0b6-20
Also, for travel use, check out Nitecore F1. It's a cheap any tiny charger, and can be used as a power bank. Pretty much solves the problem, and opens up your choices in battery.