3S 20A Lithium Battery Management System (BMS) – 12.6V with Cell Balancing

Overview

Protect your 3-cell lithium battery pack with this 3S 20A Battery Management System (BMS). Designed for 3S Li-ion battery configurations with a nominal voltage of 11.1V and a maximum charging voltage of 12.6V, this protection module continuously monitors battery operation to help ensure safe and reliable performance.

The module provides essential protection against overcharging, over-discharging, excessive current, and short circuits. Its built-in cell balancing function helps maintain more uniform voltage levels across the three cells, improving battery pack performance and lifespan.

Key Features

• 3S Battery Compatibility – Designed for three lithium-ion cells connected in series.
• 20A Continuous Discharge – Supports continuous discharge currents up to 20A.
• Overcharge Protection – Prevents individual cells from exceeding their specified voltage limits.
• Over-discharge Protection – Disconnects the load when battery voltage drops below the safe threshold.
• Overcurrent Protection – Helps protect the battery pack against excessive discharge current.
• Short-Circuit Protection – Automatically disconnects the output when a short circuit is detected.
• Built-in Cell Balancing – Helps equalize the voltage between individual cells during charging.
• Automatic Recovery – Restores normal operation after certain protection conditions are cleared.

Technical Specifications

Parameter| Value Module Type| Battery Management System (BMS) Battery Configuration| 3S (3 Cells in Series) Battery Chemistry| Li-ion Nominal Voltage| 11.1V Maximum Charging Voltage| 12.6V Continuous Discharge Current| 20A Continuous Charging Current| 10A Overcharge Protection Voltage| 4.25V ± 0.05V per cell Over-discharge Protection Voltage| 2.7V ± 0.1V per cell Balancing Detection Voltage| 4.18V Balancing Current| 30 ± 5mA Overcurrent Protection| 60 ± 10A Short-Circuit Protection| Yes Internal Resistance| Less than 20mΩ Operating Temperature| -20°C to +70°C Dimensions| 59 × 20 × 3.4mm Weight| 4.3g

Applications

• DIY lithium-ion battery packs.
• Robotics and Arduino-powered projects.
• Cordless power tools.
• Portable power supplies.
• LED lighting and backup systems.
• Solar-powered applications.
• Cordless vacuum cleaners.
• Custom battery-powered electronics.

Wiring & Usage Notes

• B-: Battery pack negative terminal.
• B1: Connection between the first and second cells.
• B2: Connection between the second and third cells.
• B+: Battery pack positive terminal.

Make sure to follow the correct wiring sequence when connecting the battery cells. Incorrect connections may permanently damage the BMS.

Important: This module is a battery protection and management circuit, not a standalone battery charger. Use a compatible 12.6V CC/CV charger for 3S lithium-ion battery packs.

Package Includes

• 1 × 3S 20A Lithium Battery Management System (BMS) Module