4S 16.8V 40A 18650 BMS Protection Board

The 4S 40A 16.8V Li-Ion Battery Protection Board (BMS) is designed to provide reliable protection and management for 4-cell lithium-ion battery packs built with 18650 cells. It enhances battery safety by monitoring charging and discharging conditions while protecting against overcharge, over-discharge, overcurrent, and short-circuit events. With support for up to 40A continuous discharge current and 20A charging current, this BMS is suitable for high-power battery packs used in electric mobility, energy storage systems, power tools, robotics, and DIY battery projects. Its compact design allows easy integration into custom battery pack assemblies.

Features

Designed for 4S lithium-ion battery packs

Compatible with 18650 lithium-ion cells

Supports 16.8V battery charging systems

Continuous discharge current up to 40A

Continuous charge current up to 20A

Overcharge protection function

Over-discharge protection function

Overcurrent protection function

Short-circuit protection function

Compact PCB design for battery integration

Suitable for high-power battery applications

Reliable battery monitoring and management

Improves battery pack safety and lifespan

Ideal for DIY and commercial battery packs

Specifications

- Model: 4 String 16.8V Lithium Battery Protection Board

- Battery Type: Lithium-Ion (18650)

- Battery Configuration: 4S

- Nominal Battery Voltage: 14.8V

- Maximum Charging Voltage: 16.8V

- Charging Voltage Range: 16.8V – 18.1V

- Maximum Continuous Charge Current: 20A

- Maximum Continuous Discharge Current: 40A

- Protection Functions: Overcharge, Over-Discharge, Overcurrent, Short Circuit

- Board Dimensions: 45 × 55 × 3.4mm

- Application: Battery Pack Protection and Management

- Installation Type: Integrated Battery Pack PCB

- Compatible Cells: 18650 Lithium-Ion Cells

- Usage: Rechargeable Battery Packs

Links

- 4S 40A 16.8V Li-Ion Battery Protection Board Manual

Tutorials

How to Safely Connect a 4S Li-Ion 40A BMS (14.4V-16.8V) for Optimal Battery Protection