Lithium Battery Protection Board BMS 3S/4S/5S 25A

The 3S/4S/5S 25A Lithium Battery Protection Board (BMS) is designed to protect compatible rechargeable lithium-ion battery packs assembled from three, four, or five cell groups connected in series. It monitors battery voltage and current conditions and disconnects the battery when specified protection limits are exceeded, helping reduce the risk of overcharging, excessive discharge, overcurrent, and short-circuit faults.

This board supports selectable 3S, 4S, and 5S configurations through the designated resistor or solder-pad setting. Each configuration requires a different charging voltage: 12.6V for 3S, 16.8V for 4S, and 21V for 5S standard lithium-ion packs. The board must be configured correctly for the number of series-connected cells before it is connected to a battery pack.

With a rated charging and discharging current of up to 25A, the module is suitable for compatible battery-powered equipment, DIY battery packs, robotics, and portable power applications. The onboard protection circuit is designed to monitor cell-group conditions and help interrupt current during fault conditions. Temperature protection is also listed for this board version.

The BMS is a protection circuit rather than a standalone charger. A suitable charger matched to the battery chemistry and selected series configuration is required. Use compatible cells with similar capacity and condition, and follow the board's wiring diagram carefully. Actual current capability depends on the installation, wiring, cooling, and operating conditions.

Features:

• Supports selectable 3S, 4S, and 5S configurations

• Rated charging current up to 25A

• Rated discharging current up to 25A

• Overcharge protection

• Over-discharge protection

• Overcurrent protection

• Short-circuit protection with automatic recovery on supported versions

• Temperature protection

• Compact PCB design for battery-pack integration

• Series configuration selectable through the designated resistor or solder-pad setting

Specifications:

• Product Type: Lithium Battery Management System / Protection Board

• Supported Configurations: 3S, 4S, and 5S

• Battery Chemistry: Standard lithium-ion / LiPo cells

• Rated Charging Current: Up to 25A

• Rated Discharging Current: Up to 25A

• 3S Full-Charge Voltage: 12.6V

• 4S Full-Charge Voltage: 16.8V

• 5S Full-Charge Voltage: 21V

• Overcharge Protection Voltage per Cell: Approximately 4.23–4.28V

• Overcharge Recovery Voltage per Cell: Approximately 4.08–4.18V

• Over-discharge Protection Voltage per Cell: Approximately 2.72–2.88V

• Over-discharge Recovery Voltage per Cell: Approximately 2.9–3.1V

• Temperature Protection: Listed for this board version

• Short-Circuit Protection: Yes

• Series Selection: Resistor or solder-pad configuration

Protection thresholds and features are based on the listed board specifications and may vary by revision. Verify the actual module before use. Cell balancing is not confirmed for this version.

Applications:

• 18650 lithium-ion battery packs

• DIY rechargeable battery assemblies

• Cordless power tools using compatible battery packs

• Robotics and mobile robot platforms

• Portable power systems

• Battery-powered electronic equipment

• Custom battery-pack development

• Embedded electronics and engineering projects