18650 Lithium Battery Charging Charger Module 3.7V 4.2V to 5V USB DIY Step Up Booster Board Mobile Power Kit For Phone - AliExpress
5v 2a 3 7v Smart Quick Charger Rechargeable Li Ion Battery Fully Charged Automatic Stop Usb Charger 26650 16340 14500 21700 18650 10440 Li Ion Lithium Batteries Flashlight Headlamp Torch Travel Charger
Vapcell U2 2A Smart mini charger USB for Li-ion / Lifepo4 / Ni-MH/Ni-Cd AAA
Device works with 3.7V batteries through a step-up to 5V. After discharge, 5V/5A supply is connected and through a lithium charger it charges the batteries. Once discharged to the point the step-up
power supply - Step up converter (3.7V to 5V) that will also charge battery! - Electrical Engineering Stack Exchange
Amazon.com: Blomiky 2 Pack 3.7V USB Charger Cable with SM-2P Plug Connector for Mini RC Amphibious Stunt Car Boat Trucks 3.7V Li-ion and Li-Po Battery / 3.7V USB 2 : Toys &
Smallest USB Type C 3.7V Lithium Battery Charger Board 4.2V Charging Module with Protection Circuit and LED Charge Indicators 5V USB-C Input - $1.79 - JacobsParts Inc
Simple 3.7 volt battery charger with auto cut off - YouTube
How to battery power a 5V microcontroller with a 3.7V lithium battery (WT32-SC01 PLUS) - General Electronics - Arduino Forum