{"title":"Efest 21700 Batteries","description":"\u003cp class=\"font-claude-response-body break-words whitespace-normal\"\u003eEfest 21700 high-drain lithium-ion cells for pack builders — a familiar, widely-available option for high-output and custom 21700 builds.\u003c\/p\u003e\n\u003cp class=\"font-claude-response-body break-words whitespace-normal\"\u003e\u003cstrong\u003eCategory text:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp class=\"font-claude-response-body break-words whitespace-normal\"\u003eEfest 21700 cells are high-drain lithium-ion cells from one of the better-known names builders recognize.\u003c\/p\u003e\n\u003cp class=\"font-claude-response-body break-words whitespace-normal\"\u003eEfest has been a familiar presence in the cylindrical cell market for years, known for high-drain cells and chargers alike. Stepping up from 18650, its 21700 cells bring more capacity and energy headroom while keeping the strong current delivery the brand is associated with — useful for high-output builds and custom packs.\u003c\/p\u003e\n\u003cp class=\"font-claude-response-body break-words whitespace-normal\"\u003eThe draw here is a recognizable brand with steady availability: a practical pick when you want a known name behind a high-drain 21700.\u003c\/p\u003e\n\u003cp class=\"font-claude-response-body break-words whitespace-normal\"\u003e\u003cstrong\u003eWhy builders choose them\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul class=\"[li_\u0026amp;]:mb-0 [li_\u0026amp;]:mt-1 [li_\u0026amp;]:gap-1 [\u0026amp;:not(:last-child)_ul]:pb-1 [\u0026amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-1 pl-8 mb-3\"\u003e\n\u003cli class=\"font-claude-response-body whitespace-normal break-words pl-2\"\u003eFamiliar, established high-drain brand\u003c\/li\u003e\n\u003cli class=\"font-claude-response-body whitespace-normal break-words pl-2\"\u003e21700 capacity and energy advantage over 18650\u003c\/li\u003e\n\u003cli class=\"font-claude-response-body whitespace-normal break-words pl-2\"\u003eBuilt for strong, steady current\u003c\/li\u003e\n\u003cli class=\"font-claude-response-body whitespace-normal break-words pl-2\"\u003eWidely available for custom pack builds\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"font-claude-response-body break-words whitespace-normal\"\u003e\u003cstrong\u003eBuilt for\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul class=\"[li_\u0026amp;]:mb-0 [li_\u0026amp;]:mt-1 [li_\u0026amp;]:gap-1 [\u0026amp;:not(:last-child)_ul]:pb-1 [\u0026amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-1 pl-8 mb-3\"\u003e\n\u003cli class=\"font-claude-response-body whitespace-normal break-words pl-2\"\u003eCustom and DIY 21700 pack builds\u003c\/li\u003e\n\u003cli class=\"font-claude-response-body whitespace-normal break-words pl-2\"\u003eHigh-output and high-drain devices\u003c\/li\u003e\n\u003cli class=\"font-claude-response-body whitespace-normal break-words pl-2\"\u003ePower-tool and portable power packs\u003c\/li\u003e\n\u003cli class=\"font-claude-response-body whitespace-normal break-words pl-2\"\u003eHigh-current flashlight and performance builds\u003c\/li\u003e\n\u003c\/ul\u003e","products":[{"product_id":"efest-21700-3700mah-battery","title":"Efest 21700 3700mAh Battery","description":"\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e3700mAh Capacity:\u003c\/strong\u003e Provides long-lasting power in the 21700 lithium-ion format.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFlat-Top Terminal:\u003c\/strong\u003e Designed for devices and battery packs that require flat-top cells.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eConsistent 3.7V Output:\u003c\/strong\u003e Reliable nominal voltage with a 4.2V maximum charge level.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e2.5V Cut-Off Voltage:\u003c\/strong\u003e Helps support proper discharge limits in compatible devices.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRechargeable Lithium-Ion Cell:\u003c\/strong\u003e Built for repeated charging and long-term use.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch4\u003eOverview\u003c\/h4\u003e\n\u003cp\u003e\n  The \u003cstrong\u003eEfest IMR 21700 3700mAh\u003c\/strong\u003e rechargeable battery offers dependable performance and extended runtime in a modern 21700\n  lithium-ion size. Featuring a flat-top design and unprotected construction, this cell is intended for devices specifically\n  engineered to operate with 21700 batteries. It delivers stable power output and is well-suited for users who need reliable energy\n  in high-capacity applications.\n\u003c\/p\u003e\n\n\u003ch4\u003eApplications \/ Uses\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e21700-compatible flashlights\u003c\/li\u003e\n  \u003cli\u003ePortable power tools and equipment\u003c\/li\u003e\n  \u003cli\u003eDIY electronics and custom battery assemblies\u003c\/li\u003e\n  \u003cli\u003eBench testing and evaluation projects\u003c\/li\u003e\n  \u003cli\u003eReplacement batteries for compatible lithium-ion devices\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch4\u003eSpecifications\u003c\/h4\u003e\n\u003ctable\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003eManufacturer:\u003c\/td\u003e\n\u003ctd\u003eEfest\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eModel:\u003c\/td\u003e\n\u003ctd\u003eIMR21700V1\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eSize:\u003c\/td\u003e\n\u003ctd\u003e21700\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003ePositive Terminal:\u003c\/td\u003e\n\u003ctd\u003eFlat Top\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eNominal Capacity:\u003c\/td\u003e\n\u003ctd\u003e3700mAh\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eNominal Voltage:\u003c\/td\u003e\n\u003ctd\u003e3.7V\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eMaximum Voltage:\u003c\/td\u003e\n\u003ctd\u003e4.2V\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eContinuous Discharge Rating (Max):\u003c\/td\u003e\n\u003ctd\u003e10A\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eCut-off Voltage:\u003c\/td\u003e\n\u003ctd\u003e2.5V\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eProtected:\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eRechargeable:\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eApprox. Dimensions:\u003c\/td\u003e\n\u003ctd\u003e21.5mm x 70.4mm\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eApprox. Weight:\u003c\/td\u003e\n\u003ctd\u003e73.12g\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0721\/2761\/1190\/files\/20190311180601_915.jpg?v=1713815829\" alt=\"Efest IMR 21700 3700mAh Flat Top Battery\"\u003e\n\n\u003chr\u003e\n","brand":"EFEST","offers":[{"title":"Default Title","offer_id":48702950474038,"sku":"EFEST-21700-37","price":9.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0721\/2761\/1190\/files\/EFEST-21700-37.jpg?v=1716995768"},{"product_id":"efest-21700-4000mah-30a-battery","title":"Efest 21700 4000mAh 30A Battery","description":"\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e4000mAh Capacity:\u003c\/strong\u003e Provides long-lasting power between charges for high-demand devices.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e30A High-Drain Output:\u003c\/strong\u003e Delivers strong, steady current for demanding applications.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFlat-Top Lithium-Ion Cell:\u003c\/strong\u003e Designed for devices that require flat-top battery contacts.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIMR Chemistry:\u003c\/strong\u003e Engineered for stable and consistent performance under load.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRechargeable \u0026amp; Compact:\u003c\/strong\u003e 21700 size offers a balance of capacity, power, and portability.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch4\u003eOverview\u003c\/h4\u003e\n\u003cp\u003e\n  The \u003cstrong\u003eEfest 21700 4000mAh\u003c\/strong\u003e rechargeable lithium-ion battery combines high capacity with strong discharge performance in a\n  compact 21700 format. With a \u003cstrong\u003e30A maximum continuous discharge rating\u003c\/strong\u003e and flat-top, unprotected design, this cell is\n  intended for devices engineered to handle high-drain lithium-ion power. It’s a reliable option for users who need sustained energy\n  and dependable output.\n\u003c\/p\u003e\n\n\u003ch4\u003eApplications \/ Uses\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e21700-compatible flashlights\u003c\/li\u003e\n  \u003cli\u003ePortable power tools and equipment\u003c\/li\u003e\n  \u003cli\u003eDIY electronics and custom battery assemblies\u003c\/li\u003e\n  \u003cli\u003eBench testing and evaluation projects\u003c\/li\u003e\n  \u003cli\u003eReplacement batteries for compatible lithium-ion devices\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch4\u003eSpecifications\u003c\/h4\u003e\n\u003ctable\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003eManufacturer:\u003c\/td\u003e\n\u003ctd\u003eEfest\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eSize:\u003c\/td\u003e\n\u003ctd\u003e21700\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eNominal Capacity:\u003c\/td\u003e\n\u003ctd\u003e4000mAh\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eNominal Voltage:\u003c\/td\u003e\n\u003ctd\u003e3.7V\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eMaximum Voltage:\u003c\/td\u003e\n\u003ctd\u003e4.2V\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eDischarge:\u003c\/td\u003e\n\u003ctd\u003e30A Maximum Continuous\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003ePositive:\u003c\/td\u003e\n\u003ctd\u003eFlat\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eProtected:\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eRechargeable:\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eDimensions:\u003c\/td\u003e\n\u003ctd\u003e21.3mm x 70.2mm\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eWeight:\u003c\/td\u003e\n\u003ctd\u003e66.37g\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0721\/2761\/1190\/files\/20190311175532_663.jpg?v=1713888381\" alt=\"Efest IMR 21700 4000mAh 30A Flat Top Battery\"\u003e\n\n\u003chr\u003e","brand":"EFEST","offers":[{"title":"Default Title","offer_id":48752322347318,"sku":"EFEST-21700-40","price":9.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0721\/2761\/1190\/files\/EFEST-21700-40.jpg?v=1716995788"},{"product_id":"efest-21700-6000mah-10a-battery","title":"Efest 21700 6000mAh 10A Battery","description":"\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e6000mAh Capacity:\u003c\/strong\u003e Designed for long runtimes with fewer recharge cycles.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e10A Steady Output:\u003c\/strong\u003e Ideal for devices that require consistent, moderate current delivery.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFlat-Top Terminal:\u003c\/strong\u003e Works with a wide range of 21700-compatible devices and battery holders.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRechargeable Lithium-Ion Cell:\u003c\/strong\u003e Built for repeated use and long-term value.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eStrong \u0026amp; Reliable Build:\u003c\/strong\u003e Rugged 21700 format with a solid, durable construction.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch4\u003eOverview\u003c\/h4\u003e\n\u003cp\u003e\n  The \u003cstrong\u003eEfest 21700 6000mAh\u003c\/strong\u003e rechargeable battery delivers exceptional capacity in a modern 21700 lithium-ion format.\n  Featuring a \u003cstrong\u003e10A maximum continuous discharge rating\u003c\/strong\u003e and flat-top design, this unprotected cell is intended for devices\n  engineered to safely manage lithium-ion power. It’s an excellent option when long runtime and dependable output are the top\n  priorities.\n\u003c\/p\u003e\n\n\u003ch4\u003eApplications \/ Uses\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e21700-compatible flashlights focused on extended runtime\u003c\/li\u003e\n  \u003cli\u003ePortable electronics with moderate power requirements\u003c\/li\u003e\n  \u003cli\u003eDIY electronics and custom battery assemblies\u003c\/li\u003e\n  \u003cli\u003eBench testing and evaluation setups\u003c\/li\u003e\n  \u003cli\u003eReplacement batteries for compatible lithium-ion devices\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch4\u003eSpecifications\u003c\/h4\u003e\n\u003ctable\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003eManufacturer:\u003c\/td\u003e\n\u003ctd\u003eEfest\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eSize:\u003c\/td\u003e\n\u003ctd\u003e21700\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003ePositive Terminal:\u003c\/td\u003e\n\u003ctd\u003eFlat Top\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eNominal Capacity:\u003c\/td\u003e\n\u003ctd\u003e6000mAh\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eNominal Voltage:\u003c\/td\u003e\n\u003ctd\u003e3.7V\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eFull Charge Voltage:\u003c\/td\u003e\n\u003ctd\u003e4.2V\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eContinuous Discharge Rating (Max):\u003c\/td\u003e\n\u003ctd\u003e10A\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eProtected:\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eRechargeable:\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eApprox. Dimensions:\u003c\/td\u003e\n\u003ctd\u003e70.9mm x 21.5mm\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eApprox. Weight:\u003c\/td\u003e\n\u003ctd\u003e74g\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003chr\u003e\n","brand":"EFEST","offers":[{"title":"Default Title","offer_id":51788164333878,"sku":"EFEST-21700-60","price":9.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0721\/2761\/1190\/files\/EFEST-21700-60.jpg?v=1744230794"}],"url":"https:\/\/18650battery.com\/collections\/efest-21700-batteries.oembed","provider":"18650Battery","version":"1.0","type":"link"}