3S 20A BMS Li-ion Battery Protection Board – 11.1V 12.6V 18650 Charger PCB

Overview

The 3S 20A BMS (Battery Management System) is a protective circuit board designed for 3-cell series (3S) Lithium-ion or Lithium-polymer battery packs. It ensures your 11.1V (nominal) / 112.6V (max) battery stays within safe operating limits. Without a BMS, Lithium cells can be easily damaged by draining them too low or charging them too high—this board prevents both, acting as a constant sentry for your power source.

Key Features 

• Triple Guard Protection: Automated safety shut-off for overcharge, over-discharge, and short-circuit conditions.

• 20A Current Capacity: Supports up to 20A of continuous discharge, making it ideal for high-brightness LEDs, DC motors, and portable speakers.

• High-Precision Voltage Detection: Monitors each of the three cells individually to ensure total pack safety.

• Compact Footprint: Small enough to be tucked inside narrow battery cases or 3D-printed enclosures.

Technical Specifications