I bought 2 round lithium battery protection boards on Taobao and asked how to connect them which one of the protection board is connected to the battery and which one is connected to the power supply (ask the seller for the positive and negative poles of the protection panel). Generally, the positive pole is connected to the positive pole of the battery. It is better to buy 2 pieces each. Be careful when welding the lithium battery when the battery is connected to a protective plate. heat
After parallel connection, you can directly charge the battery with your mobile phone charger
Note: Connect the battery with the protection plate first, then install the protection Connect the power supplies to the board in parallel