{"product_id":"hw-391-2s-20a-lithium-battery-charging-board-bms-module","title":"HW-391 2S 20A Lithium Battery Charging Board BMS Module","description":"\u003ch2\u003eHW-391 2S 20A Lithium Battery Charging Board \u0026amp; BMS Protection Module\u003c\/h2\u003e\n\u003cp\u003eThe \u003cstrong\u003eHW-391 2S 20A Lithium Battery Charging Board\u003c\/strong\u003e 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.\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e2S Configuration:\u003c\/strong\u003e Designed for 2-series lithium battery packs (7.4V nominal \/ 8.4V fully charged)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e20A Continuous Discharge:\u003c\/strong\u003e Supports high-current applications including power tools and electric drills\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBuilt-in Cell Balancing:\u003c\/strong\u003e Keeps individual cells balanced for longer battery lifespan and consistent performance\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOvercharge \u0026amp; Over-Discharge Protection:\u003c\/strong\u003e Automatically cuts off to protect your cells from damage\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOvercurrent \u0026amp; Short-Circuit Protection:\u003c\/strong\u003e Safeguards both your battery and connected devices\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompact Form Factor:\u003c\/strong\u003e Easy to integrate into custom battery packs and enclosures\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompatible Battery Models:\u003c\/strong\u003e Works with Sony VTC4A, VTC5, VTC6, and other high-drain 18650 cells\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eModel:\u003c\/strong\u003e HW-391\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eConfiguration:\u003c\/strong\u003e 2S (2-series)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMax Continuous Current:\u003c\/strong\u003e 20A\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCharge Voltage:\u003c\/strong\u003e 8.4V\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompatible Cells:\u003c\/strong\u003e 18650 lithium-ion batteries\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eConnection Wire Requirement:\u003c\/strong\u003e Copper wire of 2 mm² or larger (nickel strips are not suitable for high-current connections)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eImportant Usage Notes\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eTo 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.\u003c\/li\u003e\n  \u003cli\u003eUse OV and 8.4V connection lines with copper wire of at least 2 mm² gauge. \u003cstrong\u003eDo not use nickel strips\u003c\/strong\u003e for high-current connections.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFirst-use tip:\u003c\/strong\u003e When assembling and welding the battery pack for the first time, charge the pack fully before using the output.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWho Is This For?\u003c\/h3\u003e\n\u003cp\u003eThis 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.\u003c\/p\u003e\n\n\u003cp\u003eFor further technical guidance on lithium battery safety and handling, refer to the U.S. Consumer Product Safety Commission – Lithium-Ion Battery Safety Information.\u003c\/p\u003e\n\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003ch4\u003eQ: What does the HW-391 2S 20A Lithium Battery Charging Board do?\u003c\/h4\u003e\n\u003cp\u003eA: 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.\u003c\/p\u003e\n\u003ch4\u003eQ: What battery cells are compatible with the HW-391 BMS board?\u003c\/h4\u003e\n\u003cp\u003eA: 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.\u003c\/p\u003e\n\u003ch4\u003eQ: What wire gauge should I use when wiring the HW-391 charging board?\u003c\/h4\u003e\n\u003cp\u003eA: 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.\u003c\/p\u003e\n\u003ch4\u003eQ: Do I need to charge the battery before first use?\u003c\/h4\u003e\n\u003cp\u003eA: 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.\u003c\/p\u003e\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"What does the HW-391 2S 20A Lithium Battery Charging Board do?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"The HW-391 BMS module manages charging, cell balancing, and protection for 2-series (2S) lithium battery packs. 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