4S 100A BMS Lithium-Ion Battery Protection Board with Cell Balancing (14.8V / 16.8V)

Building a high-performance 4-cell series pack demands robust engineering, and the 4S 100A BMS Protection Board is the ultimate command center for your custom power storage. Designed specifically for four-cell (4S) Lithium-Ion (3.7V nominal / 4.2V max per cell) configurations—such as 18650 or 21700 arrays—this board actively safeguards your equipment from the severe risks of overcharging, deep discharging, and localized thermal issues.

Equipped with a thick, integrated aluminum heatsink, this board safely manages up to 100 Amps of continuous current. Crucially, it features an advanced active cell balancing architecture. Because minor manufacturing differences cause series-connected batteries to drift apart over time, the onboard balancing circuit identifies cells with higher voltage during charging and bleeds off excess energy through precision surface-mount resistors. This keeps all four cells tightly matched, maximizing your pack’s usable runtime and extending its total cycle life.

Key Features & Functional Advantages:

• Heavy-Duty 100A Continuous Rating: Built with ultra-low internal resistance MOSFETs to handle continuous industrial loads up to 100A, eliminating severe voltage drops during heavy electrical demands.

• Integrated Aluminum Heatsink: Features a pre-mounted solid metal thermal dissipation block that keeps the power components cool and reliable under high current draws.

• Precision Cell Balancing: Automatically monitors individual cell tracking during the charging phase, ensuring each series tier cuts off perfectly at 4.2V to capture 100% of the pack’s true storage potential.

• Comprehensive 4-Tier Safety Suite: Features instant automatic hardware cut-offs for over-charge voltage, deep over-discharge voltage, short-circuit protection, and over-current faults.

• Flexible Split/Same Port Wiring: Designed to accommodate both separate-port configurations (charging through one set of leads, discharging through another) and same-port configurations depending on your specific system architecture.

Perfect For:

• Inverter & Solar Storage Banks: Build highly reliable, portable 12V-class power stations (yielding roughly 14.8V nominal) to backup local communication links and remote infrastructure.

• Heavy-Duty Robotics & EV Prototyping: Supply robust, unthrottled current to heavy-duty motor drivers, planetary gearboxes, and large autonomous rovers.

• High-Capacity Power Banks: Create custom, rugged field enclosures capable of rapidly powering multiple USB-C devices, laptops, or field testing rigs away from standard mains.

• Power Tool Upgrades: The ultimate replacement pack brain for repairing or expanding heavy industrial equipment and custom high-torque power tools.

Technical Specifications:

• Configuration: 4S (4 Cells in Series)

• Supported Chemistry: Lithium-Ion (18650, 21700, 32650, etc.) with 3.7V nominal / 4.2V peak rating

• Nominal Voltage: 14.8V

• Full Charge Voltage: 16.8V (Requires a dedicated 16.8V CC/CV lithium charger)

• Maximum Continuous Current: 100A (With adequate airflow/cooling)

• Overcharge Protection Threshold: 4.25V ±0.05V per cell

• Over-Discharge Cut-off Threshold: 2.5V ±0.08V per cell

• Balancing Current: ~40mA to 60mA per cell

• Short Circuit Recovery: Automatic tracking after the load disconnection/fault removal

• Board Dimensions: Approx. 80 mm x 60 mm x 12 mm (Including heatsink)

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.