18650 BMS Board 4S 40A Balanced 16.8V

4-Series (4S) Lithium Protection: Tailored for 4-cell 18650 lithium-ion / LiPo battery packs operating at nominal 14.8V and peak 16.8V charging voltage.

Integrated Cell Balancing Circuitry: Features active passive cell voltage equalization during charging to keep all four cells balanced, extending battery pack cycle life and usable capacity.

40A Continuous Discharge Output: Delivers up to 40A continuous discharge current, making it perfect for high-power DIY battery builds, power tools, and high-drain DC motors.

Comprehensive Safety Safeguards: Built-in hardware protection against overcharging, over-discharging, short circuits, and overcurrent to ensure safe operation and prevent cell degradation.

Heavy-Duty High-Current Trace Layout: Designed with thick copper trace layers and high-power SMT MOSFETs to handle high peak currents without severe voltage drops or thermal overload.

Board Material: High-grade FR-4 glass epoxy printed circuit board with high-power SMT MOSFETs and passive balancing components.

Technical Specifications:

Series Configuration: 4S (4 Cells in series).

Charging Voltage: $16.8\text{V} - 18.0\text{V DC}$.

Continuous Discharge Current: Up to 40A.

Balance Function: Yes (Integrated passive cell balancing).

Board Color: Green PCB.

Usage Advice: Ensure all 4 lithium cells are balanced to the exact same voltage level before spot welding or soldering them to the board terminals (B-, B1 , B2, B3, B+).

Maintenance: Maintain reasonable airflow or heat sinking around the board when operating continuously near the 40A maximum load rating.

Essential High-Power 4S Protection Module: Position as an indispensable protection board for building 14.8V / 16.8V power tool battery packs, audio amplifiers, RC equipment, and solar battery storage.

Highlight 40A Output & Cell Equalization: Emphasize how 40A continuous capacity combined with cell balancing protects multi-cell battery packs from uneven wear and sudden voltage collapse.

Recommended Cross-Sell Add-ons: Pair with 18650 BMS Board 3S 40A Balanced 12.6V, 18650 BMS Board 3S 25A Balanced 12.6V, 4S 30A 14.8V LI-ION Lithium 18650 Battery, and ESD antistatic mat 50x40CM PCB Welding Mat.

Featured Collection Star: Display prominently on your Hardware Battery Management System collection page as your high-capacity 4S balanced protection board.