{"product_id":"18650-li-ion-bms-protection-board-4s-7s-16-8v-29-4v-18a-balance","title":"18650 Li-ion BMS Board 4S–7S 16.8V–29.4V 18A Balance Protection","description":"\n\u003ch2\u003e18650 Li-ion BMS Protection Board | 4S\/5S\/6S\/7S | 16.8V–29.4V | 18A Balance\u003c\/h2\u003e\n\u003cp\u003eKeep your lithium battery packs running safely and efficiently with this versatile \u003cstrong\u003eBattery Management System (BMS) Protection Board\u003c\/strong\u003e. Designed for 4S, 5S, 6S, and 7S LMO and Ternary (NMC) 18650 Li-ion cell configurations, this compact board provides active cell balancing, overcharge protection, over-discharge protection, and automatic short-circuit recovery — all in a single, space-saving PCB module. Made in Mainland China.\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWide Cell Configuration Support:\u003c\/strong\u003e Compatible with 4S, 5S, 6S, and 7S series 18650 lithium cell packs (charging voltages: 16.8V \/ 21V \/ 25.2V \/ 29.4V).\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eActive Cell Balancing:\u003c\/strong\u003e 56mA balanced current keeps all cells at equal charge levels, extending overall pack lifespan.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOvercharge Protection:\u003c\/strong\u003e Triggers at 4.25V ± 0.025V per cell, preventing dangerous overcharge conditions.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOver-Discharge Protection:\u003c\/strong\u003e Activates at 2.7V ± 0.5V per cell to guard cells from deep discharge damage.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e18A Continuous \/ 26A Instantaneous Current:\u003c\/strong\u003e Handles high-drain applications with a generous instantaneous upper-limit current of 26A.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eShort-Circuit Protection:\u003c\/strong\u003e Automatically detects short circuits and recovers after a safe delay — no manual reset required.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompact Form Factor:\u003c\/strong\u003e Measures just 60 × 40 × 6.0 mm, fitting neatly into custom battery enclosures and DIY power projects.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDurable Construction:\u003c\/strong\u003e Built with a plastic and metal composite for reliable, long-term performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003ctable style=\"width:100%; border-collapse:collapse;\"\u003e\n  \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e\u003cstrong\u003eCompatible Cell Config\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e4S \/ 5S \/ 6S \/ 7S (18650 Li-ion)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e\u003cstrong\u003eCharging Voltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e16.8V \/ 21V \/ 25.2V \/ 29.4V\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e\u003cstrong\u003eWorking Current (Max)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e18A continuous \/ 26A instantaneous\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e\u003cstrong\u003eOvercharge Voltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e4.25V ± 0.025V per cell\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e\u003cstrong\u003eOver-Discharge Voltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e2.7V ± 0.5V per cell\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e\u003cstrong\u003eBalance Current\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e56mA\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e\u003cstrong\u003eShort-Circuit Protection\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003eYes — automatic recovery after delay\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e\u003cstrong\u003eDimensions\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e60 × 40 × 6.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e\u003cstrong\u003eMaterial\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003ePlastic + Metal\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e\u003cstrong\u003ePackage Contents\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e1 × BMS Protection Board\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e\u003cstrong\u003eCountry of Origin\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003eMade in Mainland China\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eIdeal For\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eDIY 18650 lithium battery pack builds\u003c\/li\u003e\n  \u003cli\u003eE-bike, e-scooter, and power tool battery packs\u003c\/li\u003e\n  \u003cli\u003eCustom power banks and portable energy storage\u003c\/li\u003e\n  \u003cli\u003eRC vehicles and robotics battery management\u003c\/li\u003e\n  \u003cli\u003eSolar energy storage and off-grid power projects\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\/10pcs-2-pin-quick-splice-spring-wire-connectors-lock-terminals\"\u003e10pcs 2-Pin Spring Wire Connectors – Quick Splice Lock Terminals\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/12pcs-16mm-momentary-push-button-switch-1no-metal-2-pin-self-reset\"\u003e12pcs 16mm Momentary Push Button Switch 1NO Metal 2-Pin Self-Reset\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/stainless-steel-self-tapping-screws-m2-2-m4-8-phillips-wood-hinge\"\u003e10PCS Stainless Steel Self-Tapping Screws M2.2–M4.8 Phillips\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eLearn more: \u003ca href=\"https:\/\/www.epa.gov\/recycle\/used-lithium-ion-batteries\" target=\"_blank\" rel=\"noopener\"\u003eEPA guidance on lithium-ion battery handling\u003c\/a\u003e\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003ch4\u003eQ: What lithium battery chemistries is this BMS Protection Board compatible with?\u003c\/h4\u003e\n\u003cp\u003eA: This BMS board is designed for LMO (Lithium Manganese Oxide) and Ternary (NMC — Nickel Manganese Cobalt) 18650 Li-ion cells. It supports 4S, 5S, 6S, and 7S series configurations with charging voltages of 16.8V, 21V, 25.2V, and 29.4V respectively.\u003c\/p\u003e\n\u003ch4\u003eQ: Does this BMS board come with batteries or a charger?\u003c\/h4\u003e\n\u003cp\u003eA: No — this package includes only the BMS Protection Board itself (1 set). Batteries and chargers are not included and must be purchased separately.\u003c\/p\u003e\n\u003ch4\u003eQ: How does the short-circuit protection work on this board?\u003c\/h4\u003e\n\u003cp\u003eA: The board automatically detects a short-circuit event and cuts power to protect your cells and connected devices. After a brief delay, it recovers automatically — no manual reset or intervention is needed, making it ideal for unattended or enclosed battery pack installations.\u003c\/p\u003e\n\u003ch4\u003eQ: What does \"cell balancing\" mean and why does it matter?\u003c\/h4\u003e\n\u003cp\u003eA: Cell balancing ensures that all cells in a series battery pack charge and discharge to the same voltage level. Without balancing, individual cells can become mismatched over time, reducing overall capacity and potentially shortening pack life. This board provides passive balancing at 56mA to keep your cells in sync during every charge cycle.\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 lithium battery chemistries is this BMS Protection Board compatible with?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"This BMS board is designed for LMO (Lithium Manganese Oxide) and Ternary (NMC — Nickel Manganese Cobalt) 18650 Li-ion cells. It supports 4S, 5S, 6S, and 7S series configurations with charging voltages of 16.8V, 21V, 25.2V, and 29.4V respectively.\"}}, {\"@type\": \"Question\", \"name\": \"Does this BMS board come with batteries or a charger?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"No — this package includes only the BMS Protection Board itself (1 set). Batteries and chargers are not included and must be purchased separately.\"}}, {\"@type\": \"Question\", \"name\": \"How does the short-circuit protection work on this board?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"The board automatically detects a short-circuit event and cuts power to protect your cells and connected devices. 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