{"product_id":"2-pack-3-7-v-21700-rechargeable-batteries-battery-4000mah-flat-top-batteries-for-flashlight-headlamps-etc","title":"2-Pack 21700 4000mAh 3.7V Flat Top Battery – 32A High Drain for Turbo Flashlights, RC Models \u0026 Power Tools","description":"\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eProduct Description\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eDominate the Dark, the Dirt, and the Job Site\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eWhen your gear demands explosive current without a moment of hesitation, reach for this 2‑pack of 4000mAh 21700 high‑drain flat‑top cells. Each battery delivers a genuine \u003c\/span\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003e32A continuous discharge\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"\"\u003e — enough to feed the hungriest turbo flashlights, competition‑grade RC trucks, and hard‑working cordless power tools. Forget about voltage sag mid‑pull or your drill stalling under load; these cells are engineered to deliver pure, unfiltered power from the first trigger pull to the last.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eWhy 32A and 4000mAh Is the Sweet Spot\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eHigh‑drain cells often force you to choose: either massive current with pitiful runtime, or decent capacity with anaemic output. This cell gives you both. The \u003c\/span\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003e4000mAh capacity\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"\"\u003e stores approximately \u003c\/span\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003e14.8 watt‑hours\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"\"\u003e of energy (at 3.7V nominal), providing meaningful runtime in high‑current applications. Whether you’re blasting a 5000‑lumen turbo beam, tearing through a 10‑minute RC heat, or driving dozens of screws into hardwood, you’ll get the power you need and the endurance to finish the job. The 32A continuous rating is verified, not a marketing exaggeration. You can trust this cell to hold its voltage when lesser batteries collapse.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eUnprotected Flat‑Top — Built for Enthusiasts\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eWe supply this cell without an external protection PCB and with a completely flush positive terminal. Why? Because high‑drain applications demand the shortest possible electrical path and the lowest possible resistance. The flat‑top design keeps the overall length at the industry‑standard \u003c\/span\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003e70.0mm\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"\"\u003e, ensuring a perfect fit in the tightest flashlight tubes, compact tool battery shells, and densely packed RC battery trays. There’s no raised button to interfere with recessed contacts or to create uneven pressure during spot‑welding. Omitting the protection PCB eliminates the extra resistance that can choke current flow at peak loads, ensuring your devices get every single amp they demand.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cspan class=\"\"\u003eThis design does require a responsible user: you must pair these cells with a quality charger that terminates at exactly 4.2V, and you must only install them in devices that have built‑in low‑voltage cutoff. Virtually all modern turbo flashlights, brushless RC electronic speed controllers, and cordless tool motor controllers already incorporate this essential safety feature. The cells themselves provide passive multi‑layered protection through a built‑in PTC thermistor, a resealable safety vent, and a CID (Current Interrupt Device).\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eTwo Cells, Zero Downtime\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eWith two identical cells in the pack, you’re always ready. Keep one in your device and one fully charged in your bag for an instant swap when the first runs dry. Build a 2S pack for a portable power station or a high‑voltage RC setup. Or simply enjoy the peace of mind of having a spare ready for when you need it most. This is the practical, high‑performance solution for anyone who relies on their gear.\u003c\/span\u003e\u003c\/p\u003e\n\u003chr\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eKey Features\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003e32A Continuous High Drain — Genuine Rating\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eVerified 32A continuous discharge handles the most demanding turbo flashlights, RC models, and power tools without voltage sag. Short‑burst pulse capability even higher for instantaneous torque spikes.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003e4000mAh Real Capacity (14.8Wh per cell)\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eDelivers useful runtime alongside high current. Enough for extended turbo sessions, full RC heats, or multiple tool operations per charge.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eUnprotected Flat‑Top Design\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eStandard 70.0mm length and flush positive terminal fit all 21700‑compatible devices. Eliminates PCB resistance for maximum power delivery. Requires a quality 4.2V charger and a device with low‑voltage cutoff.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eUltra‑Low Internal Resistance\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eMinimized voltage drop under heavy load. At 32A, the sag is kept to a minimum, ensuring your devices stay in regulation and performance remains peak.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eStable Li‑ion Chemistry\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eMaintains a consistent 3.7V nominal voltage with a flat discharge curve. Light output, motor RPM, and torque stay predictable throughout the discharge.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003e500+ Cycle Life \u0026amp; Low Self‑Discharge\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eRecharge hundreds of times with minimal capacity loss. Stores for months at 3.6–3.7V, always mission‑ready.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eMulti‑Layered Passive Safety\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eBuilt‑in PTC thermistor, resealable safety vent, and CID protect against over‑current, over‑pressure, and short circuits.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eRugged Nickel‑Plated Steel Can\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eCorrosion‑resistant and impact‑resistant. Handles the vibrations, drops, and harsh conditions of power tools, RC vehicles, and outdoor use.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003e2‑Pack Value\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eTwo identical cells for building, swapping, or backing up. Keep your gear running without interruption.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eTechnical Parameters\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cdiv class=\"ds-scroll-area ds-scroll-area--show-on-focus-within ds-scroll-area--enabled _1210dd7 c03cafe9\"\u003e\n\u003cdiv class=\"ds-scroll-area__gutters\"\u003e\n\u003cdiv class=\"ds-scroll-area__horizontal-gutter\"\u003e\u003c\/div\u003e\n\u003cdiv class=\"ds-scroll-area__vertical-gutter\"\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cspan class=\"\"\u003eParameter\u003c\/span\u003e\u003c\/th\u003e\n\u003cth\u003e\u003cspan class=\"\"\u003eSpecification\u003c\/span\u003e\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003cbr\u003e\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eBattery Type\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003e21700 Li‑ion (unprotected, bare cell)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003ePack Count\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003e2 cells\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eNominal Capacity per Cell\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003e4000mAh (14.8Wh at 3.7V)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eNominal Voltage\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003e3.7V\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eFull Charge Voltage\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003e4.2V ± 0.05V\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eDischarge Cut‑off Voltage\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003e2.5V (use only with low‑voltage protected devices)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eStandard Charge Current\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003e2.0A (0.5C)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eMax Charge Current\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003e4.0A (1C)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eMax Continuous Discharge\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\n\u003cstrong\u003e\u003cspan class=\"\"\u003e32A\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"\"\u003e (8C) — verified\u003c\/span\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eMax Pulse Discharge\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003e40A (\u0026lt;5 seconds)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eInternal Resistance\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003e≤18mΩ (AC 1kHz, bare cell)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eProtection Circuit\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\n\u003cstrong\u003e\u003cspan class=\"\"\u003eNone\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"\"\u003e — requires external over‑discharge protection\u003c\/span\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003ePositive Terminal\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\n\u003cstrong\u003e\u003cspan class=\"\"\u003eFlat Top (flush)\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"\"\u003e — no raised nipple\u003c\/span\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eDimensions per Cell\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eApprox. 21.4mm dia. × 70.0mm length\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eWeight per Cell\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eApprox. 68g\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eCycle Life per Cell\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003e≥500 cycles (≥70% initial capacity at 0.5C charge\/discharge)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eOperating Temp. (Charge)\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003e0°C to 45°C\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eOperating Temp. (Discharge)\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003e-20°C to 75°C\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eStorage Temp. \u0026amp; Humidity\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003e-5°C to 35°C, \u0026lt;75% RH (recommend 3.6–3.7V storage)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eChemistry\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan class=\"\"\u003eNMC (Lithium Nickel Manganese Cobalt Oxide)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003cbr\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003chr\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eApplications\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003e1. Turbo Flashlights \u0026amp; High‑Lumen Hot‑Rods\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eFor FET‑driven, multi‑emitter, or custom SBT90.2 flashlights that pull 20–32A on turbo, this flat‑top cell delivers the instant current needed for maximum brightness without early step‑down. The flush terminal is mandatory for the ultra‑tight battery tubes found in enthusiast lights.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003e2. RC Cars, Trucks, Boats \u0026amp; Drones\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eBuild a 2S or 3S Li‑ion pack for 1\/10 and 1\/8 scale vehicles, or a 4S\/6S pack for high‑power drones. The 32A continuous output feeds brushless motors with relentless acceleration and top speed, while the flat‑top terminals allow clean, low‑profile spot welds.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003e3. Cordless Power Tools (Rebuilds \u0026amp; Upgrades)\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eReplace worn‑out cells in high‑torque drills, impact drivers, circular saws, and angle grinders. The 32A discharge handles the 20–30A startup spikes of professional tools, and the 4000mAh capacity provides solid runtime. The flat‑top design is the standard for welding into 5S1P or 5S2P 18V\/20V packs.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003e4. High‑Power Portable Fans \u0026amp; Industrial Cooling\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eLarge fans that draw 10–25A on high speed run powerfully and consistently. The 4000mAh capacity provides hours of strong airflow on job sites, in workshops, or during outdoor events.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003e5. DIY High‑Current Power Banks \u0026amp; Portable Inverters\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eBuild a compact power station that can fast‑charge multiple devices or run a small AC inverter. The high drain rate ensures stable output under heavy loads.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003e6. Electric Scooters \u0026amp; Light EVs (Small Packs)\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eFor small electric scooters or hoverboards using 21700 packs, these cells are an excellent choice for rebuilding with both high current and decent capacity.\u003c\/span\u003e\u003c\/p\u003e\n\u003chr\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eFAQ\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eQ1: Is the 32A rating continuous? Can it really handle that?\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eA: Yes, this cell is rated for \u003c\/span\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003e32A continuous discharge\u003c\/span\u003e\u003c\/strong\u003e\u003cspan class=\"\"\u003e, verified through testing. It can pulse even higher (up to 40A) for short bursts. We state the honest continuous rating, so you know exactly what to expect during sustained high‑drain use.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eQ2: Why is this battery unprotected and only available as a flat top?\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eA: High‑drain cells like this are designed without protection PCBs to minimize length and internal resistance — both critical for fitting tight compartments and delivering maximum current. The flat‑top terminal is the universal standard for enthusiast flashlights, tool packs, and spot‑welded RC batteries. It is completely safe when used with a quality 4.2V charger and in devices that have built‑in low‑voltage cutoff. The cell’s own PTC, vent, and CID provide passive safety layers.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eQ3: Will this flat‑top cell work in a device that originally used a button‑top battery?\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eA: It depends on the device’s positive contact design. Many high‑performance flashlights and tool packs are built specifically for flat‑top cells. If your device has a spring‑loaded contact with a physical reverse‑polarity ring, a button top might be required to bridge the gap. Check your device manual; if it specifies “flat top” or “unprotected flat top,” this cell is the correct choice.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eQ4: Can I use these 21700 cells in a device designed for 18650?\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eA: No. A 21700 cell (21mm × 70mm) is physically larger than an 18650 (18mm × 65mm). Your device must explicitly support the 21700 form factor. Never force a 21700 into an 18650 tube.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eQ5: How hot does this cell get at 32A continuous?\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eA: With a low internal resistance, heat generation is well‑managed. The cell will become warm — typically reaching around 65–75°C after several minutes of sustained 32A — but remains within safe operating limits. Allow cooling between heavy discharge runs for maximum longevity.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eQ6: Can I charge these batteries at 4A?\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eA: Yes, 4A (1C) is the maximum charge current. For optimal cycle life, we recommend the standard 2A (0.5C) rate. Fast charging generates more heat and may slightly reduce long‑term capacity.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eQ7: How should I store the spare cell?\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eA: Keep it in a plastic battery case or silicone sleeve, away from metal objects and moisture. For storage longer than one month, bring the voltage to about 3.6–3.7V (roughly 50% charge). Check every 3 months and recharge if the voltage drops below 3.0V. Never store a fully depleted cell.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan class=\"\"\u003eQ8: Can I bring these batteries on an airplane?\u003c\/span\u003e\u003c\/strong\u003e\n\u003cbr\u003e\u003cspan class=\"\"\u003eA: Yes. Each cell is approximately 14.8Wh, well under the 100Wh IATA limit for carry‑on luggage. Insulate the terminals and carry them in your hand luggage.\u003c\/span\u003e\u003c\/p\u003e","brand":"OneAndes","offers":[{"title":"Default Title","offer_id":51454119543030,"sku":"OAS186","price":15.98,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0819\/2753\/6886\/files\/2pack-21700-4000mAh-universal-main_841c0dd3-38f8-4229-8ab4-fb367bac1ef6.webp?v=1786965303","url":"https:\/\/oneandes.com\/products\/2-pack-3-7-v-21700-rechargeable-batteries-battery-4000mah-flat-top-batteries-for-flashlight-headlamps-etc","provider":"OneAndes","version":"1.0","type":"link"}