{"product_id":"5s-21v-li-ion-bms-protection-circuit-board-power-tools","title":"5S 21V Li-Ion BMS Protection Circuit Board for Power Tools","description":"\n\u003ch2\u003e5S 21V Lithium Battery BMS Protection Circuit Board\u003c\/h2\u003e\n\u003cp\u003eKeep your lithium battery packs running safely and efficiently with this \u003cstrong\u003e5S 21V Battery Management System (BMS) Protection Circuit Board\u003c\/strong\u003e. Designed for power tools and electric vehicles, this compact PCB module provides multi-layer protection to extend battery life and maintain stable performance across demanding applications.\u003c\/p\u003e\n\n\u003cp\u003eMade in Mainland China.\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eComprehensive Protection:\u003c\/strong\u003e Overvoltage, undervoltage, overcurrent, overcharge, and overheat protection for each individual cell in the pack.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e3 MOS Design:\u003c\/strong\u003e High-quality MOSFET configuration for reliable switching and stable current management in power tool applications.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWide Compatibility:\u003c\/strong\u003e Suitable for most electric power tools, electric scooters, electric bicycles, electric motorcycles, electric tricycles, electric vehicles, and various electric appliances.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAnti-Vibration Stability:\u003c\/strong\u003e Engineered for rugged environments — an ideal match for 21V torque wrenches, impact drills, and angle grinders.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReusable \u0026amp; Durable:\u003c\/strong\u003e Constructed from plastic and metal components for long-lasting, reusable service.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePer-Cell Monitoring:\u003c\/strong\u003e Independently monitors and protects each cell in the battery pack for balanced performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eConfiguration\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e5S (5 cells in series)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eVoltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e21V\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMaterial\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003ePlastic + Metal\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eBattery Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eLi-Ion \/ Lithium\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eReusability\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eReusable\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eBattery Included\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCharger Included\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCountry of Origin\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eMainland China\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003ePackage Contents\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e1 × 5S 21V BMS Protection Circuit Board (PCB)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eImportant Notes\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eProduct color may vary slightly from images due to monitor brightness and lighting conditions. Please refer to the actual product received.\u003c\/li\u003e\n  \u003cli\u003ePlease allow slight measurement deviation for listed dimensions.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eRelated Products You May Like\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/1pc-10g-high-grade-silicon-grease-lubricant-o-lubrication-good-odorless-smoothness-for-o-rings-tube-silicone-grease-lubricant\"\u003e1PC 10g High Grade Silicone Grease Lubricant for O-Rings\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/1pc-large-capacity-battery-storage-organizer-box-batteries-not-included-vintage-beer-crate-appearance-holds-30-aaa-batteries\"\u003e1PC Large Capacity Battery Storage Organizer Box\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/3pcs-silicone-sealant-scraper-set-multi-functional-caulking-nozzle-tools-for-tile-floor-joints-grout-finishing-and-renovation\"\u003e3PCS Silicone Sealant Scraper Set – Multi-Functional Tools\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eLearn more: \u003ca href=\"https:\/\/www.energystar.gov\/products\" target=\"_blank\" rel=\"noopener\"\u003eENERGY STAR product efficiency guidance\u003c\/a\u003e\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003ch4\u003eQ: What does a 5S 21V BMS protection circuit board do?\u003c\/h4\u003e\n\u003cp\u003eA: A 5S 21V BMS (Battery Management System) protection circuit board monitors and protects a lithium battery pack made up of 5 cells in series. It safeguards the pack against overvoltage, undervoltage, overcurrent, overcharge, and overheating — helping maintain safe operation and prolong battery life for power tools and electric vehicles.\u003c\/p\u003e\n\u003ch4\u003eQ: Is this BMS board compatible with my power tools?\u003c\/h4\u003e\n\u003cp\u003eA: Yes — this 5S 21V BMS module is designed to be compatible with most 21V lithium-powered electric tools, including torque wrenches, impact drills, and angle grinders, as well as electric scooters, bicycles, motorcycles, tricycles, and other electric appliances.\u003c\/p\u003e\n\u003ch4\u003eQ: Does this board come with a battery or charger?\u003c\/h4\u003e\n\u003cp\u003eA: No. The package includes only the BMS protection circuit board (PCB). Batteries and chargers are not included and must be sourced separately.\u003c\/p\u003e\n\u003ch4\u003eQ: Can I reuse this BMS board if I rebuild my battery pack?\u003c\/h4\u003e\n\u003cp\u003eA: Yes. This BMS protection circuit board is designed to be reusable, making it a cost-effective choice for battery pack rebuilds and replacements.\u003c\/p\u003e\n\u003c!-- production-packaging-notice --\u003e\n\u003ch3\u003eProduction \u0026amp; Packaging Notice\u003c\/h3\u003e\n\u003cp\u003eTo 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.\u003c\/p\u003e\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"What does a 5S 21V BMS protection circuit board do?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"A 5S 21V BMS (Battery Management System) protection circuit board monitors and protects a lithium battery pack made up of 5 cells in series. 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