2S 8.4V BMS Battery Protection Board with Balancing | 1–5 Pcs
2S 8.4V BMS Battery Protection Board with Balancing | 1–5 Pcs
2S LiFePO4 Battery Management System (BMS) with Cell Balancing
Keep your 2S lithium battery packs running safely and efficiently with the HUXUAN 2S 8.4V BMS Protection Board. Designed for 32650 and 18650 cell configurations, this compact board delivers reliable multi-layer protection — all in a lightweight plastic and metal housing measuring just 46 × 22 mm. Made in Mainland China.
Key Specifications
- Configuration: 2S (2-cell series)
- Nominal Voltage: 6.4V / 7.4V
- Charge Cutoff Voltage: 8.4V
- Continuous Discharge Current: 10A
- Compatible Cells: 32650, 18650 Li-Ion / LiFePO4
- Dimensions: 46 × 22 mm
- Material: Plastic + Metal
- Pack Options: 1 pc or 5 pcs
Built-In Protection Functions
- ✅ Overcharge Protection — cuts off charging when cells reach maximum voltage
- ✅ Over-Discharge Protection — prevents cells from draining below safe thresholds
- ✅ Short Circuit Protection — instantly disconnects load in fault conditions
- ✅ Overcurrent Protection — limits current to safe operating levels
- ✅ Cell Balancing — equalizes voltage across both cells for extended cycle life
Ideal Applications
This BMS board is perfectly suited for a wide variety of DIY and professional battery pack builds, including:
- Massager battery packs
- LED light backup power supplies
- 12V electronic products
- Solar street light battery packs
- Monitoring/surveillance backup power supplies
Wiring Guide
- B+ → Positive pole of the battery
- B− → Negative pole of the battery
- MB → Connection point between Battery 1 and Battery 2 (mid-point)
- P+ → Positive pole of the charge/discharge terminal (shared)
- P− → Negative pole of the charge/discharge terminal (shared)
Tip: When assembling battery packs, ensure cells are matched in voltage, capacity, and internal resistance as closely as possible. Cells should be near the rated 3.7V. If there is no output after assembly, charge the pack at 8.4V to activate the board.
Important Usage Notes
This board is not suitable for use with: lithium iron phosphate batteries (LiFePO4 chemistry packs), xenon/HID (hernia) lamps, hand drill battery packs, electric fishing machine packs, electric bicycle battery packs, children's ride-on car batteries, motors rated 550 class or above, or 1W fisheye LED lights. Please verify compatibility before purchase.
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Learn more: EPA guidance on lithium-ion battery handling
Frequently Asked Questions
Q: What battery types are compatible with this 2S BMS protection board?
A: This BMS board is designed for 2-cell series (2S) Li-Ion battery packs using 18650 or 32650 cylindrical cells operating at a nominal voltage of 6.4V–7.4V with an 8.4V charge cutoff. It is not intended for standard lithium iron phosphate (LiFePO4) chemistry packs or high-draw applications such as power tools or electric bikes.
Q: Does the board support both charging and discharging through the same terminals?
A: Yes. The P+ and P− terminals are shared for both charging and discharging, making wiring straightforward. Simply connect your charge/discharge leads to P+ and P−, and wire the battery cells to B+, MB, and B− as described in the wiring guide above.
Q: What is cell balancing and why does it matter?
A: Cell balancing is a function that equalizes the voltage between the two cells in the series pack. Over time, cells can drift apart in voltage, which can reduce overall capacity and shorten pack lifespan. The built-in balancing circuit on this BMS automatically keeps both cells at matched voltages, helping maintain performance and extend the number of usable charge cycles.
Q: Is the 5-pack a better value for DIY projects?
A: Absolutely. If you are building multiple battery packs — for example, several LED backup lights or solar storage units — the 5-piece option provides a cost-effective supply. All boards in the pack are identical in specification to the single unit.
Production & Packaging Notice
To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.