Shipping Rate

The shipping costs are based on weight, volume, delivery address and subtotal of the order.
Indication of shipping costs:

Standard mail*: €2.50
Parcel Basic NL: €5.95 (free from €100)
Parcel International: See link below
Pickup in Eindhoven: €0.00

*The system will automatically decide if standard mail is possible. If not, then only Parcel and Pickup are available.
See this page for extra shippings options and explanation about the shipping costs: Shipping

QSKJ Li-ion/Li-Po Protection Circuit (BMS) - 4S

QSKJ Li-ion/Li-Po Protection Circuit (BMS) - 4S

Quick Shipping

Ordered before 17:00 on a business day? We ship the same day!

Model: BMS4S25A-2.8-4.25
SKU: 002932
Availability: In Stock
... Piece(s) Sold
€3.50 Ex Tax: €2.89
Stock Indication:
Quantity: Add to Cart

A Battery Management System (BMS) for a 3S battery pack. With this circuit you can safely make a battery pack of 3 series Li-ion/Li-Po batteries (cells). The circuit protects the battery pack against short circuits, overvoltage and undervoltage. 


  • Charging voltage: 16.8V DC
  • Maximum charging current: 25A*
  • Maximum continuous discharge current: 25A*
  • Short circuit protection: 60 ± 5A
  • Overcharge protection voltage (per cell/battery):  4.25 ± 0.025V
  • Discharge protection voltage (per cell/battery): 2.80 ± 0.08V
  • Balance function: No**
  • Possibility to solder a 10kΩ NTC
  • Dimensions PCB: See images

*Note: These are the maximum currents of the BMS circuit. Connected batteries may not be able to handle this current!
**Note: The chip does not support a balancing, after some time the voltages of the cells can diverge slightly. This circuit is for cell protection only.

Pin description (See the images for the connection diagram):

  • B-: Min cell/battery 1
  • A: Not connected
  • B: Plus cell/battery 1, min cell/battery 2
  • B1: Plus cell/battery 2, min cell/battery 3
  • B2: Plus cell/battery 3, min cell/battery 4
  • B+: Plus cell/battery 4
  • P+: Plus output battery pack
  • P-: Min output battery pack

Use the P+ and P connections to charge and discharge the battery pack.

Caution: Making a Li-ion/Li-Po battery pack requires knowledge. Only make the package if you know what you are doing. Incorrectly connecting the batteries and the BMS can cause the batteries to catch fire, or even explode.

There are no reviews for this product.

Write a review

First Name:

Your email from your order: (will not be exposed)

Your Review:Note: HTML is not translated!

Rating: Bad           Good