{"product_id":"21v-2a-lithium-battery-charger-18650-4-series-li-ion","title":"21V 2A Li-Ion Battery Charger for 4-Series 18650 Packs | Qme","description":"\n\u003ch2\u003e21V 2A Smart Lithium Battery Charger — 4-Series 18650 Li-Ion Compatible\u003c\/h2\u003e\n\u003cp\u003eKeep your 18V lithium battery packs fully charged and performing at their best with this compact, intelligent 21V 2A charger. Designed for 4-series 18650 Li-ion battery packs, it delivers reliable, controlled charging with multiple built-in protection circuits — so you can charge with confidence every time.\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOutput Voltage:\u003c\/strong\u003e 21V DC — optimized for 4-series 18650 lithium battery packs (nominal 18V)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCharging Current Options:\u003c\/strong\u003e 0.5A and 1A selectable output for flexible, battery-friendly charging\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDC Connector:\u003c\/strong\u003e 5.5mm x 2.1mm barrel plug for broad compatibility\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompact Form Factor:\u003c\/strong\u003e 94 x 47 x 33 mm — easy to store and transport\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e2 Color Options:\u003c\/strong\u003e Choose the style that suits your setup\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInput Over-Current Protection:\u003c\/strong\u003e When input current exceeds 2A, a built-in fuse automatically cuts off power to prevent internal circuit abnormalities and reduce fire risk\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOutput Current Protection:\u003c\/strong\u003e Charging current is regulated within a safe range to preserve battery health and maximize battery lifespan\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eShort-Circuit \u0026amp; Over-Voltage Protection:\u003c\/strong\u003e Multiple safety layers guard against common electrical faults\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLED Charging Indicator:\u003c\/strong\u003e Clear visual status so you always know when charging is complete\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eClip Included:\u003c\/strong\u003e Convenient clip for easy handling and placement during charging\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWho Is This Charger For?\u003c\/h3\u003e\n\u003cp\u003eWhether you use 18650 lithium cells in power tools, DIY battery packs, portable lighting, or other 4-series Li-ion applications, this charger provides a safe and consistent top-up every time. The compact dimensions make it ideal for workshop benches, storage drawers, or on-the-go use.\u003c\/p\u003e\n\n\u003ch3\u003eSafety \u0026amp; Standards\u003c\/h3\u003e\n\u003cp\u003eFor guidance on safe lithium battery charging and handling, visit the U.S. Consumer Product Safety Commission — Lithium-Ion Battery Safety resource for best practices.\u003c\/p\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOutput Voltage:\u003c\/strong\u003e 21V DC\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInput:\u003c\/strong\u003e Standard AC (compatible with included plug type)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCharging Current:\u003c\/strong\u003e 0.5A \/ 1A\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompatible Battery:\u003c\/strong\u003e 4-Series 18650 Li-ion (18V nominal)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eConnector:\u003c\/strong\u003e 5.5mm x 2.1mm DC barrel plug\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDimensions:\u003c\/strong\u003e 94 x 47 x 33 mm\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eColor Options:\u003c\/strong\u003e 2 available\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Qme\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003ch4\u003eQ: What type of batteries is this 21V lithium charger compatible with?\u003c\/h4\u003e\n\u003cp\u003eA: This charger is designed for 4-series 18650 Li-ion battery packs with a nominal voltage of 18V and a full-charge voltage of 21V. It uses a standard 5.5mm x 2.1mm DC barrel connector, making it compatible with a wide range of DIY and commercial battery pack configurations.\u003c\/p\u003e\n\u003ch4\u003eQ: What safety protections does this lithium battery charger include?\u003c\/h4\u003e\n\u003cp\u003eA: The charger features input over-current protection (fuse cut-off above 2A), output current regulation to protect battery health, and short-circuit\/over-voltage protection. These multiple safety layers help prevent electrical faults and extend the life of your battery pack.\u003c\/p\u003e\n\u003ch4\u003eQ: What is the difference between the 0.5A and 1A charging settings?\u003c\/h4\u003e\n\u003cp\u003eA: The 0.5A setting provides a slower, gentler charge — ideal for conditioning or maintaining batteries. The 1A setting charges faster and is suited for everyday top-ups. Both settings stay within safe parameters to protect battery longevity.\u003c\/p\u003e\n\u003ch4\u003eQ: How do I know when charging is complete?\u003c\/h4\u003e\n\u003cp\u003eA: The charger features a built-in LED indicator that changes status when the battery is fully charged, giving you a clear and easy visual confirmation without having to monitor voltage levels manually.\u003c\/p\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"What type of batteries is this 21V lithium charger compatible with?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"This charger is designed for 4-series 18650 Li-ion battery packs with a nominal voltage of 18V and a full-charge voltage of 21V. It uses a standard 5.5mm x 2.1mm DC barrel connector, making it compatible with a wide range of DIY and commercial battery pack configurations.\"}}, {\"@type\": \"Question\", \"name\": \"What safety protections does this lithium battery charger include?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"The charger features input over-current protection (fuse cut-off above 2A), output current regulation to protect battery health, and short-circuit\/over-voltage protection. These multiple safety layers help prevent electrical faults and extend the life of your battery pack.\"}}, {\"@type\": \"Question\", \"name\": \"What is the difference between the 0.5A and 1A charging settings?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"The 0.5A setting provides a slower, gentler charge — ideal for conditioning or maintaining batteries. The 1A setting charges faster and is suited for everyday top-ups. Both settings stay within safe parameters to protect battery longevity.\"}}, {\"@type\": \"Question\", \"name\": \"How do I know when charging is complete?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"The charger features a built-in LED indicator that changes status when the battery is fully charged, giving you a clear and easy visual confirmation without having to monitor voltage levels manually.\"}}]}\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:\/\/vpggdm-rp.myshopify.com\/\"}, {\"@type\": \"ListItem\", \"position\": 2, \"name\": \"Phone \u0026 Cable Accessories\", \"item\": \"https:\/\/vpggdm-rp.myshopify.com\/collections\/phone-cable-accessories\"}, {\"@type\": \"ListItem\", \"position\": 3, \"name\": \"21V 2A Li-Ion Battery Charger for 4-Series 18650 Packs | Qme\", \"item\": \"https:\/\/vpggdm-rp.myshopify.com\/products\/21v-2a-lithium-battery-charger-18650-4-series-li-ion\"}]}\u003c\/script\u003e","brand":"Qme","offers":[{"title":"whit clip \/ US PLUG \/ 2A","offer_id":49684141867222,"sku":"14:175#whit clip;249:201452293#US PLUG;822:200003392","price":226.94,"currency_code":"USD","in_stock":true},{"title":"DC5.5-2.1MM \/ EU PLUG \/ 2A","offer_id":49684141899990,"sku":"14:350850#DC5.5-2.1MM;249:201452292#EU PLUG;822:200003392","price":22.52,"currency_code":"USD","in_stock":true},{"title":"whit clip \/ UK PLUG \/ 2A","offer_id":49684141932758,"sku":"14:175#whit clip;249:201452294#UK PLUG;822:200003392","price":242.44,"currency_code":"USD","in_stock":true},{"title":"whit clip \/ EU PLUG \/ 2A","offer_id":49684141965526,"sku":"14:175#whit clip;249:201452292#EU PLUG;822:200003392","price":226.94,"currency_code":"USD","in_stock":true},{"title":"DC5.5-2.1MM \/ AU PLUG \/ 2A","offer_id":49684141998294,"sku":"14:350850#DC5.5-2.1MM;249:201452295#AU PLUG;822:200003392","price":23.6,"currency_code":"USD","in_stock":true},{"title":"DC5.5-2.1MM \/ US PLUG \/ 2A","offer_id":49684142031062,"sku":"14:350850#DC5.5-2.1MM;249:201452293#US PLUG;822:200003392","price":22.52,"currency_code":"USD","in_stock":true},{"title":"whit clip \/ AU PLUG \/ 2A","offer_id":49684142063830,"sku":"14:175#whit clip;249:201452295#AU PLUG;822:200003392","price":242.44,"currency_code":"USD","in_stock":true},{"title":"DC5.5-2.1MM \/ UK PLUG \/ 2A","offer_id":49684142096598,"sku":"14:350850#DC5.5-2.1MM;249:201452294#UK PLUG;822:200003392","price":23.6,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0827\/5243\/8486\/files\/S30ada42985f54e398fefac8be0f38e62G.webp?v=1785157981","url":"https:\/\/qmeboost.com\/products\/21v-2a-lithium-battery-charger-18650-4-series-li-ion","provider":"Qme","version":"1.0","type":"link"}