2-Pack Lishen 21700-5000SD 5000mAh 3.6V Flat Top Battery – 10A Continuous / 15A Pulse for LED Flashlights, Fans, Cameras & Toys

The Endurance Champion for Your Everyday Gear

Why settle for a cell that forces you to choose between runtime and reliability? The Lishen 21700-5000SD is engineered for users who want both: a genuine 5000mAh capacity that keeps devices running for hours on end, and a robust 10A continuous discharge with 15A pulse capability to handle the demands of modern LED flashlights, portable fans, camera equipment, and motorized toys. This 2‑pack gives you the freedom to keep one cell in your device and one fully charged, eliminating downtime whether you're on a night hike, filming a wedding, or cooling down on a hot day.

Honest Discharge Ratings — No Marketing Hype

The 5000SD is rated for 10A continuous discharge, verified through stringent testing. This means it can sustain a steady 10‑amp load without voltage sag, overheating, or premature capacity loss — perfectly matched to the current draws of high‑performance single‑LED and multi‑LED flashlights, USB‑rechargeable fans, field monitors, and motorized toys. The 15A pulse capability provides an extra safety margin for instantaneous surges — the split‑second when a device's motor starts or a flashlight turbo mode engages. We don't inflate the numbers; we give you the real specifications so you can trust what you're buying.

Flat‑Top and Unprotected — The Universal Standard

This battery is supplied as an unprotected, flat‑top bare cell. The flush positive terminal measures exactly 70.0mm from end to end, the industry standard for 21700‑compatible devices. It slides effortlessly into the tightest flashlight tubes, the recessed battery bays of portable fans, and the compact battery sleds of camera adapters and electronic toys. Omitting the external protection PCB reduces internal resistance by eliminating an unnecessary layer of circuitry — critical for maintaining voltage stability under load. Naturally, this design expects you to use a quality charger with precise 4.2V termination and to install the cell only in devices that feature built‑in low‑voltage cutoff. Every modern LED flashlight, USB‑rechargeable fan, camera accessory, and electronic toy on the market already incorporates this protection, making this cell a safe, drop‑in upgrade. The cell itself also includes a built‑in PTC thermistor, resealable safety vent, and CID for passive multi‑layered protection.

Where 5000mAh Transforms Your Experience

The 5000mAh capacity stores approximately 18.5 watt‑hours of energy — roughly 2.5 times what a standard 2000mAh 18650 can hold. In practical terms, a single 5000SD cell powers a 300‑lumen flashlight for over 5 hours on medium mode, or an entire night on a low 50‑lumen setting. A USB desk fan on low speed hums for 10–12 hours, keeping your workspace comfortable through a full shift. A camera field monitor drawing a steady 1–3A runs for hours without a battery swap, letting you focus on the creative work rather than power management. Motorized toys — RC cars, robots, ride‑on vehicles — see dramatically extended playtime compared to standard 2000–3000mAh packs. And because you receive two identical cells, you can build a 2S pack for higher‑voltage applications, keep a spare fully charged for zero‑downtime operation, or simply have a backup always ready when you need it most.

Long‑Life Chemistry and Robust Construction

Lishen employs a high‑stability NMC (Nickel‑Manganese‑Cobalt) formulation that provides a flat 3.6V nominal discharge curve. With an internal resistance of ≤25mΩ, voltage sag at the full 10A is a minimal 0.25V — your flashlight beam stays bright, your fan speed stays constant, and your camera monitor doesn't flicker. The cell is rated for over 500 full charge/discharge cycles with at least 70% capacity retention, and its low self‑discharge rate allows you to store the spare cell for months at the recommended 3.6–3.7V without significant power loss. The nickel‑plated steel can resist corrosion, impact, and the everyday bumps of portable electronics. Built‑in passive safety layers — a PTC thermistor, a resealable safety vent, and a CID (Current Interrupt Device) — provide robust protection against over‑current, over‑pressure, and short circuits.

Key Features

• 5000mAh Genuine High Capacity (18.5Wh per cell)
  Stores enough energy for 5+ hours of 300‑lumen flashlight light, 10–12 hours of fan cooling, or weeks of device standby. No more constant battery swaps.

• 10A Continuous / 15A Pulse Discharge
  Verified 10A continuous output handles medium‑drain devices with ease. 15A pulse provides extra headroom for motor startups and turbo mode surges.

• Unprotected Flat‑Top Design
  Standard 70.0mm length and flush positive terminal fit all 21700‑compatible devices. Eliminates PCB resistance for more efficient power delivery. Requires a quality 4.2V charger and device with low‑voltage cutoff.

• Stable NMC Chemistry & Flat Discharge
  Maintains a consistent 3.6V nominal voltage from 4.2V down to 2.5V. Light output, fan speed, and motor torque stay predictable throughout the discharge.

• Low Internal Resistance (≤25mΩ)
  Voltage drop at 10A is only ~0.25V. Minimal energy lost as heat, maximum energy delivered to your device.

• 500+ Cycle Life & Low Self‑Discharge
  Recharge hundreds of times with minimal capacity fade. Stores for months at 3.6–3.7V, always ready when you need it.

• Multi‑Layered Passive Safety
  Built‑in PTC thermistor, resealable safety vent, and CID protect against over‑current, over‑pressure, and short circuits.

• Rugged Nickel‑Plated Steel Can
  Corrosion‑resistant and impact‑resistant. Handles the bumps, drops, and daily wear of portable fans, flashlights, cameras, and toys.

• 2‑Pack Value
  Two identical cells for uninterrupted power. Keep one in your device and one fully charged — ideal for long outings, back‑to‑back shoots, or all‑day job site use.

Technical Parameters

Applications

1. LED Flashlights & EDC Torches
   Perfect for single‑LED and multi‑LED lights that need maximum runtime. The 5000mAh capacity delivers 5+ hours of 300‑lumen medium light or a full night on low mode. The flat‑top design fits ultra‑tight enthusiast flashlight tubes (ZebraLight, Noctigon, Emisar) and spring‑loaded hosts alike.

2. Portable Fans for All‑Day Cooling
   USB desk fans, camping fans, stroller fans, and job‑site fans run 10–12 hours on low speed with this cell. The stable 10A output keeps airflow strong even on high settings. Flat top fits recessed fan battery bays perfectly.

3. Camera Monitors, Video Lights & Accessories
   External field monitors, LED panels, and camera battery adapters that accept 21700 cells benefit from the massive capacity. Fewer battery swaps mean uninterrupted shooting — ideal for weddings, events, and long studio sessions.

4. Motorized Toys & Ride‑On Vehicles
   Upgrade RC cars, robots, and children's ride‑on toys with a 2S or 3S pack built from these cells. The 5000mAh capacity dramatically extends playtime, and the 10A discharge provides the current needed for startup surges and sustained driving.

5. DIY Power Banks & Hobby Electronics
   The flat‑top cell is ready for spot welding into custom 2S or 3S packs for high‑capacity USB‑C chargers, Bluetooth speakers, and portable power stations. Consistent 5000mAh capacity simplifies cell matching.

6. Surveillance & Smart Home Devices
   Wireless cameras, doorbells, and motion sensors can run for weeks or months on a single charge. Low self‑discharge ensures reliability during long idle periods.

7. Portable Medical & Industrial Equipment
   Handheld scanners, portable nebulizers, and thermal printers that rely on 21700 power appreciate the combination of long runtime and stable 10A output, ensuring consistent operation through extended shifts.

FAQ

Q1: Is the 15A rating continuous or pulse? What's the sustained discharge?
A: The 15A rating is the maximum pulse discharge for short bursts (under 5 seconds). The cell is rated for 10A continuous discharge. We specify both figures honestly so you know exactly what to expect. For sustained 10A operation, the cell performs reliably without overheating or excessive voltage sag.

Q2: Why is this battery unprotected and only available as a flat top?
A: Lishen designed the 5000SD as a bare cell for pack building and high‑capacity applications. A protection PCB would add unwanted length and resistance; a button top would interfere with tight compartments and spot welding. The flat‑top, unprotected design is the universal standard for enthusiast flashlights, fan bays, camera adapters, and DIY packs. It's safe when used with a quality 4.2V charger and in devices with built‑in low‑voltage cutoff — which virtually all modern electronics already feature. The cell's PTC, vent, and CID provide passive protection.

Q3: Will this flat‑top cell work in a device that originally used a button‑top battery?
A: It depends on the device. Many high‑performance flashlights and electronic devices are designed specifically for flat‑top cells. If your device has a spring‑loaded positive contact with a physical reverse‑polarity ring, a button top may be required to make contact. Check your device manual: if it specifies "flat top" or "unprotected flat top," this cell is the correct choice.

Q4: Can I use these 21700 cells in a device designed for 18650?
A: 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.

Q5: How long will a 5000mAh battery run my portable fan?
A: On low speed (drawing about 0.4–0.5A), approximately 10–12 hours. On high speed (about 1.5–2A), around 3–4 hours. The 5000mAh capacity is nearly 2.5 times a standard 2000mAh 18650, providing a dramatic runtime improvement.

Q6: Can I charge this battery at 5A?
A: Yes, 5A (1C) is the maximum charge current. For optimal cycle life, we recommend the standard 2.5A (0.5C) rate. Fast charging generates more heat and may slightly reduce long‑term capacity.

Q7: How should I store the spare cell?
A: 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.

Q8: Can I bring these batteries on an airplane?
A: Yes. Each cell is approximately 18.5Wh, well under the 100Wh IATA limit for carry‑on luggage. Insulate the terminals and carry them in your hand luggage.