DIY Battery
In this video, I will show you how to make a 9-volt rechargeable battery and use it anywhere, and save on battery costs. All you need is two 3.7V batteries, a voltage booster module, a charging module and a non-usable 9V battery body. In this project, I will show you how to make the charging module very small so that it fits more comfortably inside the 9-volt battery.
Credit Matrix Farm