The 2S 8.4V Lithium Battery Protection Board is a compact, high-performance safety module designed to protect 2-cell (2S) lithium-ion and lithium-polymer battery packs from overcharge, over-discharge, and overcurrent conditions. With a 5A continuous working current and 7A current limit, this board is engineered for moderate to high-drain applications where standard protection boards cannot handle the current requirements.
At the heart of the board is a BMS (Battery Management System) protection circuit that continuously monitors the voltage of each cell and the total pack current, disconnecting the load or charger if any parameter exceeds safe limits. This protects both the battery pack and your connected devices from damage, extending battery lifespan and ensuring safe operation.
The board provides three critical protection functions:
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Overcharge protection — Disconnects the charger when any cell voltage reaches approximately 4.25V to 4.3V, preventing damage from excessive charging.
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Over-discharge protection — Disconnects the load when any cell voltage drops to approximately 2.5V to 3.0V, preventing deep discharge that can permanently damage the battery.
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Overcurrent protection — Disconnects the output when current exceeds 7A, protecting against short circuits and excessive loads.
The 2S configuration means the board manages two cells in series, balancing the voltage across both cells to ensure they charge and discharge evenly. This cell balancing function is critical for maintaining pack health and maximizing lifespan. Without proper balancing, one cell can become overcharged or over-discharged, leading to premature failure or safety hazards.
The 5A continuous working current and 7A current limit make this board suitable for applications such as portable power banks, RC vehicles, drone battery packs, portable speakers, power tools, and other devices that draw moderate to high current. The 7A current limit provides a safety margin, disconnecting the output if current exceeds safe levels.
The board features a solder pad design that supports both direct soldering and spot welding. The exposed pads allow you to solder wires directly to the board, while also being compatible with spot-welded nickel strips for professional battery pack assembly. The board includes B+, B-, BM (mid-point), P+, and P- pads for battery and output connections.
Important Note: This protection board is designed for 2S (2-cell) 7.4V/8.4V lithium battery packs. For other configurations, a different protection board or BMS should be used. Always verify the voltage and current ratings match your application before installation.
Whether you are building a custom 2S battery pack, assembling an 18650 pack for a portable device, or adding safety protection to an RC vehicle, the 2S 8.4V Lithium Battery Protection Board provides a reliable, high-current solution. It is suitable for individual makers, students, and businesses purchasing in bulk for product development or educational programs.
Features
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2S dual-cell protection — Manages two cells in series with cell balancing
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5A working current — Continuous discharge capability for moderate to high-drain applications
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7A current limit — Overcurrent protection with safety margin
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Comprehensive protection — Overcharge, over-discharge, and overcurrent protection
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Cell balancing function — Ensures even charge and discharge across both cells
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Solder pad design — Supports both direct soldering and spot welding
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Wide compatibility — Works with 18650, polymer, and prismatic lithium cells
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Wide application range — Power banks, RC vehicles, drones, portable devices
Technical Specifications
| # | Parameter | Specification |
|---|---|---|
| 1 | Compatible Battery | 2S 7.4V lithium-ion / lithium-polymer |
| 2 | Full Charge Voltage | 8.4V |
| 3 | Working Current | 5A continuous |
| 4 | Current Limit | 7A |
| 5 | Overcharge Protection Voltage | ~4.25V – 4.3V per cell |
| 6 | Over-discharge Protection Voltage | ~2.5V – 3.0V per cell |
| 7 | Cell Balancing | Yes |
| 8 | Connection Type | Solder pads (spot welding supported) |
