The 3S 12.6V 100A Lithium Battery Protection Board with Balance is a high-power BMS (Battery Management System) designed to protect 3-cell (3S) lithium-ion and lithium-polymer battery packs from overcharge, over-discharge, and overcurrent conditions. With a 100A continuous current rating, separate charge/discharge ports, and a balance function, this board is engineered for the most demanding high-power applications — from electric vehicles and energy storage systems to high-power tools and industrial equipment.
At the heart of the board is a BMS 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 in high-power applications.
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 100A, protecting against short circuits and excessive loads.
The 100A continuous rating makes this board suitable for very high-power applications such as electric vehicles, electric scooters, energy storage systems, and industrial equipment. This is a significant step up from standard 3S boards that typically max out at 20A–50A, filling an important gap for very high-current 3S applications.
The separate charge and discharge ports are a key feature of this BMS. The charge port (C-) and discharge port (P-) are independent, allowing you to use different connectors and wiring for charging and discharging. This is particularly useful for high-power applications where the charge current and discharge current requirements differ significantly. It also allows for more flexible system design.
The balance function is another critical feature. During charging, the board monitors the voltage of each cell and bleeds off excess charge from cells that reach full voltage before others. This ensures all cells in the pack reach the same voltage, maximizing pack capacity and lifespan. Without proper balancing, one cell can become overcharged or over-discharged, leading to premature failure or safety hazards.
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-, BM1, BM2 (mid-points), P+, P-, C+, and C- pads for battery, discharge, and charge connections.
Important Note: This BMS is designed for 3S (3-cell) 11.1V/12.6V lithium battery packs with a maximum continuous current of 100A. For higher-current applications, a BMS with a higher current rating should be used. Always verify the voltage and current ratings match your application before installation. Ensure all wiring and connections are rated for the maximum current your application will draw.
Whether you are building a high-power 3S battery pack for an electric vehicle, assembling an energy storage system, or adding safety protection to industrial equipment, the 3S 12.6V 100A Lithium Battery Protection Board provides a reliable, high-power solution. It is suitable for individual makers, engineers, and businesses purchasing in bulk for product development or industrial applications.
Features
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3S triple-cell protection — Manages three cells in series with cell balancing
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100A continuous current — Very high-power capability for demanding applications
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Separate charge/discharge ports — Independent C- and P- connections for flexible system design
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Balance function — Ensures even charge and discharge across all three cells
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Comprehensive protection — Overcharge, over-discharge, and overcurrent protection
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Solder pad design — Supports both direct soldering and spot welding
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Compact PCB design — Sized for high-power battery packs
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Wide application range — Electric vehicles, energy storage, industrial equipment
Technical Specifications
| # | Parameter | Specification |
|---|---|---|
| 1 | Compatible Battery | 3S 11.1V lithium-ion / lithium-polymer |
| 2 | Full Charge Voltage | 12.6V |
| 3 | Continuous Discharge Current | 100A |
| 4 | Overcharge Protection Voltage | ~4.25V – 4.3V per cell |
| 5 | Over-discharge Protection Voltage | ~2.5V – 3.0V per cell |
| 6 | Balance Function | Yes |
| 7 | Charge/Discharge Ports | Separate (C-, P-) |
| 8 | Connection Type | Solder pads (spot welding supported) |
