Lithium battery – 1S protection boards

Some of my projects use a single Lithium cell for power, and the ready availability of low-cost battery protection boards offers opportunity for better projects.

IMG_1472Above, a 1S board rated at 4A and which sells for about A$1 posted in lots of 5.


New and good quality
Use BM112 protection chip + AO8810 MOS tube
The protection board is used to protect the battery overcharge, over discharge, so can’t use as a charger,when you want to charge the battery you need to use the dedicated charger,because the protective board has a time to response to the short circuit, can’t to connect too large instant impact current, such as drills and so on

The main performance parameters:
1. PCB Size: 39 * 4 * 2mm
2. Overcharge protection voltage: 4.2750 ± 25MV
3. Over-discharge protection voltage: 2.88 ± 75MV
4. The overcurrent protection: 4-8A
5. Continue working current: > 4A

Note: Only for the equipment which instant start-up current less than 4A,those starting current instant is great, such as high-current motors, drills, etc., are not suitable for use.


Above are protected battery assemblies based on the board and a 1200mAh LiPo (sells for about A$4) and Panasonic 18650 Li-ion 3400mAh (sells for about A$12). The connectors used are 3A rated JST RCY connectors as used in RC battery applications and readily available with tails for way less than A$1 each set.

The 18650 cell has tags spot welded to the battery contact points, the LiPo has contact tags as supplied.

To use these, the power source needs to supply about 4.5V so as to ensure charging when necessary. The power source needs to be current limited unless you choose to depend on the protection boar’s limit.