BMS often ship in locked state: no output voltage is available at the output pins. Locked state is also entered whenever over-current protection was triggered. To unlock the BMS, connect it to a charger. If you did not add a dedicated charger board, apply the appropriate charging voltage to its output terminal.
When connecting batteries to your BMS, make sure to use wires with sufficient diameter for the anticipated high currents.
When designing battery packs, use batteries of same type and same state of charge only. It is recommended you fully charge all batteries before connecting. All batteries must have the same voltage (voltage difference less than 0.05V). Do not mix batteries from different vendors, types, capacity, or age.
4A
LiIon LiPo For currents up to 4A, you can use a small BMS:
The board shape suggests that this BMS was designed to be used with two 18650 batteries but can of course be used with any LiIon or LiPo batteries.
There are no connectors located on the back:
Connect the batteries like this:
- First battery string to B- (-) and BM (+)
- Second battery string to BM (-) and B+ (+)
The output voltage is available at P+ and P-.
Specs
| Protection | Threshold |
|---|---|
| Over-Charge | >4.3V (delay time 1s), recovery voltage 4.05V |
| Over-Discharge | <3V (detection time 128ms), recovery voltage 3.2V |
| Over-Current | 9.8A (delay time 12ms), auto-recovery |
| Short Circuit | yes (delay time <50us), auto-recovery |
| Continuous Current | 4A |
| Size | 35x17mm |
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(content created Mar 21, 2024)