4S 40A Balanced BMS Battery Protection Board for 18650 Li-ion Batteries – 16.8V

4S 40A Balanced BMS Battery Protection Board – 16.8V

Build a compatible four-series lithium-ion battery pack with this 4S 40A Balanced Battery Management System (BMS). Designed for standard lithium-ion cells, this protection board is advertised with a 40A continuous discharge rating and a cell-balancing function.

Key Features

• 4S battery configuration: For four lithium-ion cell groups connected in series.

• 16.8V full-charge voltage: For standard Li-ion cells rated at 4.2V per cell group.

• Advertised 40A continuous discharge current: Actual safe current depends on cooling, wiring, connectors and battery-cell capability.

• Balanced version: Designed to help balance cell-group voltages during charging.

• Advertised protection functions: Listings describe overcharge, over-discharge, overcurrent and short-circuit protection.

• Compact PCB: Reported dimensions for the balanced version are approximately 46 × 60 × 3.4 mm; verify before installation.

Technical Specifications

• Product type: 4S balanced BMS protection board

• Battery chemistry: Standard lithium-ion

• Configuration: 4S

• Nominal voltage: 14.4V or 14.8V, depending on the cells' nominal rating

• Full-charge voltage: 16.8V

• Advertised continuous discharge current: Up to 40A

• Advertised continuous charge current: Up to 20A

• Reported balancing current: Approximately 100mA; supplier confirmation recommended

• Reported dimensions: Approximately 46 × 60 × 3.4 mm

• Package: 1 × 4S 40A balanced BMS board

Potential Applications

Depending on the battery cells and load requirements, this board may be suitable for selected battery-powered tools, LED systems, sprayers and DIY battery-pack projects.

Installation and Safety

Use only with a compatible 4S standard Li-ion battery pack and a suitable 16.8V CC/CV charger. This board is a protection circuit, not a standalone battery charger.

Confirm the terminal labels and wiring sequence against the instructions for your exact board. Use compatible cells with similar condition and voltage, appropriate wiring, and adequate heat dissipation. Never assume the advertised 40A rating is suitable for every battery pack or installation.