li-ion 18650 BMS Charger PCB Prot. Board, 4S 14.8V~16.8V 40A


This is a 4 cell BMS for 14.8Vdc Lithium battery pack with 16.8Vdc max charge voltage and 40A max discharge current.


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*Disclaimer: The images are merely illustrative.

This is a 4 cell BMS for 14.8Vdc Lithium battery pack with 16.8Vdc max charge voltage and 40A max discharge current.
  • Charging voltage: DC 16.8V~17V
  • Continuous discharge current: 40A maximum (if the heat dissipation environment is not good, please reduce the load current)
  • Continuous charging current: up to 20A
  • Balance Version Product size: 45x60x4mm
  • Enhance Version Product size: 44x55x4mm
  • Applicable choice: applicable to the nominal voltage of 3.7V, fully charged 4.2V lithium battery           (including 18650, 26650, polymer lithium battery), can be drilled below 170W


Note 1: For drill aplications, the successful start of the drill requires three 15C-20C power battery, or six 10C-15C power battery (ordinary 18650 can not start the drill!!).

Note 2: strictly according to map wiring 0V, 4.2V, 8.4V, 12.6V, 16.8V, do not deliberately short circuit.

Note 3: When the load of the brush motor is used, try to connect a non-polar capacitor (withstand voltage above 25V, capacity 10uF-100uF) to the motor's positive and negative terminals to prevent the reverse spike from the motor. Break the MOS tube.

Note 4: 4 groups of batteries in series, please ensure that the voltage of each group of batteries, if not the same, please fill each battery separately and then use in series. The Discharge test, the voltage drop faster battery that group is poor battery.

The figure below shows the module discharge diagram. The battery is 4 cells. The connected battery needs to meet the 40A discharge current. It can be realized by paralleling the battery or purchasing a battery with a large discharge current. For example, the battery 2000mAH, the discharge multiple 10C, then only need 4 series 2 and the maximum current can reach the discharge current 40A, stable discharge requires 4 strings 4 and can be, and need to pay attention to heat dissipation, the discharge battery power will drop rapidly.
Balance Version:

Discharging Test

Enhance Version:

Discharging Test Enhance

The picture below shows the battery charging diagram, 4 series of batteries, the actual full charge, voltage 16.8V, charging voltage DC17V-18V, charging current depends on the battery connected, the maximum does not exceed 20A.
Balance Version:

Balance Example

Enhance Version:

Balance Example Enhance


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