{"product_id":"5s-21v-30a-bms-battery-protection-board-for-power-tools","title":"5S 21V 30A BMS Battery Protection Board for Power Tools","description":"\n\u003ch2\u003e5S 21V BMS Battery Protection Circuit Board for Power Tools\u003c\/h2\u003e\n\u003cp\u003eKeep your lithium-ion battery packs running safely and efficiently with this high-performance \u003cstrong\u003e5S 21V Battery Management System (BMS) Protection Board\u003c\/strong\u003e. Designed specifically for 5-series Li-ion battery packs used in electric power tools, this compact circuit board delivers comprehensive charge and discharge protection, extending the life of your battery cells and keeping your tools performing at their best.\u003c\/p\u003e\n\n\u003cp\u003eFeaturing a dedicated 5S lithium battery IC processor, the board continuously monitors real-time voltage, charge\/discharge current, and ambient temperature across each individual cell — giving you multi-layer protection in a single compact unit. Made in Mainland China.\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e5S Li-Ion Compatible:\u003c\/strong\u003e Engineered for 5-cell series lithium-ion battery packs (18V\/21V systems)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOvercharge Protection:\u003c\/strong\u003e Prevents cells from exceeding safe voltage limits (4.25V per cell) with a 1-second protection delay\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOver-Discharge Protection:\u003c\/strong\u003e Automatically cuts off discharge before cells drop to damaging low-voltage levels\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eShort-Circuit Protection:\u003c\/strong\u003e Instantly detects and responds to short-circuit events to safeguard your batteries and tools\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHigh Continuous Discharge Current:\u003c\/strong\u003e Rated at 40A\/50A continuous, with a peak capacity of up to 100A — ideal for demanding power tool applications\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNTC Temperature Sensing:\u003c\/strong\u003e Built-in NTC thermistor monitors ambient temperature to prevent thermal damage\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eUltra-Low Power Consumption:\u003c\/strong\u003e Working current ~25µA; quiescent current ~6µA — minimal drain on your battery pack\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e5S 21V Indicator Included:\u003c\/strong\u003e Visual charge status indication for easy monitoring\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWide Operating Temperature Range:\u003c\/strong\u003e -40°C to +85°C (RH \u0026lt;75%)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompact Design:\u003c\/strong\u003e Measures just 9 × 6.2 × 1.6 cm for easy fitment in most power tool battery housings\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003ctable\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eModel\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e18V\/21V High-Power Protection Board\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCharge Voltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e21V\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSingle Cell Charge Voltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e4.25V\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eContinuous Discharge Current\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e40A \/ 50A, Max 100A\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eOvercharge Protection Delay\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e1 Second\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eBMS Rating\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e5S 50A Max 100A with NTC\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eIndicator\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e5S 21V Indicator\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eOperating Temperature\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e-40°C to +85°C, RH \u0026lt;75%\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eDimensions\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e9 × 6.2 × 1.6 cm\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003ePackage Contents\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e1 × BMS Protection Board\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\u003eMade in Mainland China\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eWhy Proper Battery Protection Matters\u003c\/h3\u003e\n\u003cp\u003eSelecting and correctly installing the right BMS protection board is crucial to maximising battery longevity and operational safety. This board's multi-protection design ensures your Li-ion cells are shielded from the most common causes of premature battery failure — overcharging, deep discharge, and short circuits.\u003c\/p\u003e\n\n\u003cp\u003eIf you're working on power tool maintenance or DIY electronics projects, you may also find these related products useful:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/air-compressor-pressure-gauge-0-10-0-12-0-25-bar-hydraulic-diy\"\u003eAir Compressor Pressure Gauge 0-10\/0-12\/0-25 Bar | DIY Tool\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/electromagnetic-induction-tester-coil-motherboard-fault-detector\"\u003eElectromagnetic Induction Tester – Coil \u0026amp; Circuit Fault Detector\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eImportant Notes\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eProduct photos may not reflect exact size — please refer to listed dimensions.\u003c\/li\u003e\n  \u003cli\u003eMinor measurement differences may occur due to manual measurement.\u003c\/li\u003e\n  \u003cli\u003eActual colour may vary slightly from images due to monitor display differences.\u003c\/li\u003e\n  \u003cli\u003eBattery and charger are \u003cstrong\u003eNOT\u003c\/strong\u003e included.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eLearn more: \u003ca href=\"https:\/\/www.osha.gov\/personal-protective-equipment\" target=\"_blank\" rel=\"noopener\"\u003eOSHA on personal protective equipment\u003c\/a\u003e\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003ch4\u003eQ: What battery configuration is this BMS protection board designed for?\u003c\/h4\u003e\n\u003cp\u003eA: This BMS protection board is designed for 5-series (5S) lithium-ion battery packs with a nominal voltage of 18V and a maximum charge voltage of 21V. It is commonly used in electric power tool battery replacements and rebuilds.\u003c\/p\u003e\n\n\u003ch4\u003eQ: What protections does this 5S BMS circuit board provide?\u003c\/h4\u003e\n\u003cp\u003eA: The board provides overcharge protection (triggers at 4.25V per cell), over-discharge protection, and short-circuit protection. It also features NTC temperature monitoring to protect against thermal extremes, ensuring safe and reliable operation in power tool applications.\u003c\/p\u003e\n\n\u003ch4\u003eQ: What is the maximum discharge current this protection board can handle?\u003c\/h4\u003e\n\u003cp\u003eA: The board supports a continuous discharge current of 40A to 50A and can handle peak surge currents of up to 100A, making it suitable for high-demand power tools that require bursts of high current during operation.\u003c\/p\u003e\n\n\u003ch4\u003eQ: Is the battery or charger included with this protection board?\u003c\/h4\u003e\n\u003cp\u003eA: No — this listing is for the BMS protection board only. The battery cells and charger are not included and must be sourced separately.\u003c\/p\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"What battery configuration is this BMS protection board designed for?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"This BMS protection board is designed for 5-series (5S) lithium-ion battery packs with a nominal voltage of 18V and a maximum charge voltage of 21V. It is commonly used in electric power tool battery replacements and rebuilds.\"}}, {\"@type\": \"Question\", \"name\": \"What protections does this 5S BMS circuit board provide?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"The board provides overcharge protection (triggers at 4.25V per cell), over-discharge protection, and short-circuit protection. 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The battery cells and charger are not included and must be sourced separately.\"}}]}\u003c\/script\u003e\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\": \"https:\/\/schema.org\", \"@type\": \"BreadcrumbList\", \"itemListElement\": [{\"@type\": \"ListItem\", \"position\": 1, \"name\": \"Home\", \"item\": \"https:\/\/n8ande-60.myshopify.com\/\"}, {\"@type\": \"ListItem\", \"position\": 2, \"name\": \"Home page\", \"item\": \"https:\/\/n8ande-60.myshopify.com\/collections\/frontpage\"}, {\"@type\": \"ListItem\", \"position\": 3, \"name\": \"5S 21V 30A BMS Battery Protection Board for Power Tools\", \"item\": \"https:\/\/n8ande-60.myshopify.com\/products\/5s-21v-bms-battery-protection-board-power-tool-li-ion\"}]}\u003c\/script\u003e","brand":"Axl","offers":[{"title":"21V 6MOS","offer_id":43692158386237,"sku":"14:771#21V 6MOS","price":17.47,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0671\/3439\/0333\/files\/S007c9cf5bdd24b77aa351d75d4d539e0D.webp?v=1790175238","url":"https:\/\/qtiply.com\/products\/5s-21v-30a-bms-battery-protection-board-for-power-tools","provider":"QTP","version":"1.0","type":"link"}