HW-391 2S 20A Lithium Battery Charging Board BMS Module
HW-391 2S 20A Lithium Battery Charging Board BMS Module
HW-391 2S 20A Lithium Battery Charging Board & BMS Protection Module
The HW-391 2S 20A Lithium Battery Charging Board is a compact, high-performance Battery Management System (BMS) module designed for 2-series 18650 lithium battery packs. Whether you're building a DIY power tool battery pack, an electric drill battery, or a custom lithium battery project, this module delivers reliable charging, balancing, and protection in one efficient board.
Key Features
- 2S Configuration: Designed for 2-series lithium battery packs (7.4V nominal / 8.4V fully charged)
- 20A Continuous Discharge: Supports high-current applications including power tools and electric drills
- Built-in Cell Balancing: Keeps individual cells balanced for longer battery lifespan and consistent performance
- Overcharge & Over-Discharge Protection: Automatically cuts off to protect your cells from damage
- Overcurrent & Short-Circuit Protection: Safeguards both your battery and connected devices
- Compact Form Factor: Easy to integrate into custom battery packs and enclosures
- Compatible Battery Models: Works with Sony VTC4A, VTC5, VTC6, and other high-drain 18650 cells
Specifications
- Model: HW-391
- Configuration: 2S (2-series)
- Max Continuous Current: 20A
- Charge Voltage: 8.4V
- Compatible Cells: 18650 lithium-ion batteries
- Connection Wire Requirement: Copper wire of 2 mm² or larger (nickel strips are not suitable for high-current connections)
Important Usage Notes
- To successfully power an electric drill, you will need either 2 high-drain (10C–20C) power cells or 4 standard-rate cells — high-discharge cells such as the Sony VTC4A, VTC5, or VTC6 are recommended.
- Use OV and 8.4V connection lines with copper wire of at least 2 mm² gauge. Do not use nickel strips for high-current connections.
- First-use tip: When assembling and welding the battery pack for the first time, charge the pack fully before using the output.
Who Is This For?
This BMS charging board is ideal for electronics hobbyists, DIY battery pack builders, RC enthusiasts, and anyone who needs a reliable, all-in-one protection and charging solution for 2S lithium battery configurations.
For further technical guidance on lithium battery safety and handling, refer to the U.S. Consumer Product Safety Commission – Lithium-Ion Battery Safety Information.
Frequently Asked Questions
Q: What does the HW-391 2S 20A Lithium Battery Charging Board do?
A: The HW-391 BMS module manages charging, cell balancing, and protection for 2-series (2S) lithium battery packs. It provides overcharge protection, over-discharge protection, overcurrent protection, and short-circuit protection — all in a compact board designed for 18650 lithium-ion cells operating at up to 20A continuous discharge current.
Q: What battery cells are compatible with the HW-391 BMS board?
A: This board is compatible with standard 18650 lithium-ion cells. For high-current applications such as electric drills or power tools, high-drain cells such as the Sony VTC4A, VTC5, or VTC6 are strongly recommended. You will need 2 high-drain cells (10C–20C rated) or 4 standard-rate cells for optimal performance.
Q: What wire gauge should I use when wiring the HW-391 charging board?
A: For safe and efficient operation at 20A, use copper wire with a minimum cross-section of 2 square millimeters (2 mm²). Do not use nickel strips, as they cannot safely handle the required current load for high-drain applications.
Q: Do I need to charge the battery before first use?
A: Yes. When assembling and soldering the battery pack for the first time, it is important to fully charge the battery before enabling any output. This ensures the BMS protection circuitry initializes correctly and the cells are properly balanced from the start.