2S 3A BMS Lithium-Ion Battery Charger & Protection Board (7.4V / 8.4V)

The 2S 3A BMS Lithium-Ion Protection Board is a highly miniaturized battery management system designed specifically for two-cell (2S) 18650 or LiPo configurations. While massive power-tool BMS boards handle extreme current, this ultra-slim module is engineered for smaller, more delicate electronics that require steady 7.4V power at a maximum continuous draw of 3 Amps. It seamlessly serves a dual purpose: safely distributing 8.4V charging current across both cells, while simultaneously acting as an invisible safety net during discharge.

Because of its incredibly tiny footprint (barely wider than the edge of an 18650 cell), it is designed to be soldered and heat-shrinked directly against the battery pack, creating a streamlined, self-contained power source. It automatically monitors the voltage thresholds of the two series-connected cells, instantly cutting the circuit to prevent irreversible damage caused by overcharging, deep discharging, and accidental short-circuits.

Key Features & Functional Advantages:

• Ultra-Compact Footprint: Measuring only 36mm long and roughly 6mm wide, it sits perfectly flush against the bridge of a standard 18650 dual-battery pack, allowing for extremely low-profile power integration.

• Continuous 3A Discharge: Efficiently delivers a steady 3 Amps of current with brief transients up to 5 Amps, making it the ideal controller for low-drain 7.4V motors, LED arrays, and microcontrollers.

• 4-Tier Active Protection: Constantly monitors the battery pack to cut off the circuit in the event of over-voltage (over-charging), under-voltage (deep discharging), over-current events, and hard short-circuits.

• Auto-Recovery System: If the board triggers a protection cut-off (such as detecting a short circuit), the system will automatically restore power output once the fault condition is removed and the charging voltage is applied.

• Simple 5-Pad Wiring: Clearly labeled solder pads (B+, B-, and the middle balancing bridge MB) make it incredibly straightforward to wire up custom 2S packs on your workbench.

Perfect For:

• DIY 7.4V Battery Packs: The essential "brain" for safely bundling raw, unprotected 18650 or 21700 lithium-ion cells into reusable custom power banks.

• Small RC Toys & Robotics: Provides safe, steady voltage to lower-torque 7.4V DC gear motors and micro servos found in tabletop rovers and custom STEM robotics.

• Portable Lighting: Ensures safe operation and prevents deep-discharge degradation in custom-built 7.4V LED flashlights and portable camera lighting rigs.

• Low-Power Audio: Protects the dedicated 2S power supply inside compact, custom-built Bluetooth speakers and portable desktop radios.

Technical Specifications:

• Configuration: 2S (2 Cells in Series)

• Supported Chemistry: Lithium-Ion (18650, 21700, etc.) or Lithium Polymer (LiPo)

• Nominal Pack Voltage: 7.4V

• Full Charge Voltage: 8.4V (Requires an appropriate 8.4V CC/CV charging source)

• Maximum Continuous Current: 3A

• Peak / Transient Current: 5A

• Overcharge Detection Voltage: 4.25V to 4.35V (±0.05V) per cell

• Over-Discharge Detection Voltage: 2.3V to 3.0V (±0.05V) per cell

• Quiescent Standby Current: < 3µA (Will not rapidly drain the battery while sitting idle)

• Internal Resistance: < 45mΩ

• Approximate Dimensions: 36 mm x 6.5 mm x 2 mm

Ensure your order is placed by 2PM to guarantee next-day delivery! Our commitment to prompt service includes a 24-hour delivery system through our network of carriers, aimed at ensuring your package arrives right on schedule.

Please note, a delivery fee of €4.99 applies for orders under €50. For those in remote areas, be aware that our couriers may apply an extra surcharge. This additional fee helps cover the costs of transporting your items to harder-to-reach locations.