Currently, power is supplied from one or two Li-Ion 3.7V batteries in series, or the equivalent DC power supply.
Considered battery chargers
1) Li-ion charger
https://soldered.com/product/li-ion-charger/
https://github.com/SolderedElectronics/Li-ion-charger-hardware-design
https://eu.mouser.com/ProductDetail/Soldered/333013?qs=sGAEpiMZZMs5TKDXZEoCqOJ%252BWtJg0exjwbn3KWhGmkEFhOaAA0LmMA%3D%3D
2) Li-ion charger with protection
https://soldered.com/product/li-ion-charger-with-protection/
https://github.com/SolderedElectronics/Li-ion-charger-with-protection-hardware-design
https://eu.mouser.com/ProductDetail/Soldered/333014?qs=sGAEpiMZZMs5TKDXZEoCqOJ%252BWtJg0exjNv7rV%2FQFNRhneIj2%2FqDp%252BA%3D%3D
Considered DC/DC converters
https://www.amazon.com/QEBIDUM-MT3608-Synchronous-Non-Isolated-Adjustable/dp/B0B9Y8NFDN
