https://www.amazon.com/Opus-BT-Intelligent-Compatible-Batteries/dp/B01852TBOU
Fixed that link for you
I have one of these. It will max charge and then discharge and then charge and give you max maH.
I use the Opus charger. It charges Li-ion/NiCd/NiMh batteries. It has advanced features that you could use later but also auto charging. It also comes with a charger unlike others what have an USB port which means you have to have your own.
https://www.amazon.com/Opus-BT-Intelligent-Compatible-Batteries/dp/B01852TBOU