4S 15A Battery Management Systems (BMS)

BMS For Four Battery Strings And 15A Max Current

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.


LiIon LiPo For currents up to 15A, a board with four powerful MosFET like this one can be used:

Connect the batteries like this:

  • First battery string to B- (-) and VL (+)
  • Second battery string to VL (-) and VM (+)
  • Third battery string to VM (-) and VH (+)
  • Forth battery string to VH (-) and B+ (+)

The terminals are accessible both from top and bottom.

The output voltage is available at P+ and P-.


Protection Threshold
Over-Charge >4.25V
Over-Discharge 2.5V
Over-Current 20-30A
Short Circuit yes,resettable
Continuous Current 15A (10A w/o heat sink)
Size 50x22x4mm


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(content created Mar 16, 2024)