{"product_id":"21v-100a-21700-li-ion-battery-case-bms-led-power-tool-diy-kit","title":"21V 100A 21700 Li-ion Battery Case Kit with BMS \u0026 LED Display","description":"\u003cp\u003eBuild your own high-performance \u003cstrong\u003e21V lithium-ion battery pack\u003c\/strong\u003e with this versatile \u003cstrong\u003e21700 battery case kit\u003c\/strong\u003e — designed for power tool compatibility with 5, 10, or 15-cell configurations. Featuring a robust BMS (Battery Management System) board, LED power display, and 4 MOSFETs, this DIY battery housing gives you a reliable, customizable energy solution for your workshop tools.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eNote:\u003c\/strong\u003e This is a battery case\/holder kit only — \u003cem\u003ebatteries are not included\u003c\/em\u003e. You supply your own 21700 lithium cells (5, 10, or 15 cells depending on your chosen configuration) to assemble the pack. No after-sales service is included with this kit.\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFlexible Cell Configuration:\u003c\/strong\u003e Supports 5-cell, 10-cell, or 15-cell 21700 lithium battery arrangements to suit different capacity needs\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e21V \/ 100A Output:\u003c\/strong\u003e High-current BMS circuitry handles demanding power tool loads with confidence\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBuilt-in BMS Protection:\u003c\/strong\u003e Battery Management System with 4 MOSFETs provides overcharge, over-discharge, and short-circuit protection\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLED Power Display:\u003c\/strong\u003e Real-time battery level indicator keeps you informed at a glance\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDurable Construction:\u003c\/strong\u003e Plastic + metal housing built to withstand the rigors of workshop and job-site use\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e3 Color Options:\u003c\/strong\u003e Choose the finish that suits your style or tool setup\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePower Tool Compatible:\u003c\/strong\u003e Designed to fit Makita-style tool interfaces\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eVoltage:\u003c\/strong\u003e 21V\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaximum Current:\u003c\/strong\u003e 100A\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCell Compatibility:\u003c\/strong\u003e 21700 Li-ion cells\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCell Configurations:\u003c\/strong\u003e 5S \/ 10S \/ 15S (5, 10, or 15 cells)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBMS:\u003c\/strong\u003e Included (4 MOSFET design)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDisplay:\u003c\/strong\u003e LED power indicator\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Plastic + Metal\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eColors Available:\u003c\/strong\u003e 3 options\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBatteries Included:\u003c\/strong\u003e No — user-supplied 21700 cells required\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat's in the Box\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e1× Battery case\/housing kit (plastic + metal shell)\u003c\/li\u003e\n  \u003cli\u003e1× BMS PCBA board with 4 MOSFETs\u003c\/li\u003e\n  \u003cli\u003e1× LED power display module\u003c\/li\u003e\n  \u003cli\u003eAssorted connection hardware\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eFor guidance on safe lithium battery handling and assembly best practices, refer to the U.S. Consumer Product Safety Commission – Lithium Battery Safety resources.\u003c\/p\u003e\n\n\u003cp\u003eLearn more: \u003ca href=\"https:\/\/en.wikipedia.org\/wiki\/Battery_pack\" target=\"_blank\" rel=\"noopener\"\u003eBattery pack\u003c\/a\u003e\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003ch4\u003eQ: What does this 21700 battery case kit include?\u003c\/h4\u003e\n\u003cp\u003eA: This kit includes the plastic and metal battery case housing, a BMS (Battery Management System) PCBA board with 4 MOSFETs, an LED power display module, and assembly hardware. \u003cstrong\u003e21700 lithium cells are not included\u003c\/strong\u003e — you need to supply your own 5, 10, or 15 cells depending on the configuration you choose.\u003c\/p\u003e\n\n\u003ch4\u003eQ: Which power tools is this 21V battery case compatible with?\u003c\/h4\u003e\n\u003cp\u003eA: This battery case is designed to be compatible with Makita-style 21V power tool interfaces, making it a great DIY option for assembling a custom replacement or backup battery pack for cordless drills, saws, and other compatible tools.\u003c\/p\u003e\n\n\u003ch4\u003eQ: Is it safe to assemble a lithium battery pack at home?\u003c\/h4\u003e\n\u003cp\u003eA: This kit is intended for users with experience in DIY electronics and lithium battery assembly. The built-in BMS provides important protections (overcharge, over-discharge, short-circuit), but proper handling of lithium cells is essential. Always follow lithium battery safety guidelines and ensure cells are matched in capacity and charge state before assembly.\u003c\/p\u003e\n\n\u003ch4\u003eQ: What cell configurations does this case support?\u003c\/h4\u003e\n\u003cp\u003eA: The case supports three configurations: 5-cell (5S), 10-cell (10S), and 15-cell (15S) using 21700 format lithium-ion batteries, allowing you to build packs with different capacity outputs to suit your tool's requirements.\u003c\/p\u003e\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"What does this 21700 battery case kit include?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"This kit includes the plastic and metal battery case housing, a BMS (Battery Management System) PCBA board with 4 MOSFETs, an LED power display module, and assembly hardware. 21700 lithium cells are not included — you need to supply your own 5, 10, or 15 cells depending on the configuration you choose.\"}}, {\"@type\": \"Question\", \"name\": \"Which power tools is this 21V battery case compatible with?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"This battery case is designed to be compatible with Makita-style 21V power tool interfaces, making it a great DIY option for assembling a custom replacement or backup battery pack for cordless drills, saws, and other compatible tools.\"}}, {\"@type\": \"Question\", \"name\": \"Is it safe to assemble a lithium battery pack at home?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"This kit is intended for users with experience in DIY electronics and lithium battery assembly. 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