EVE 21700-40P 4000mAh 3.7V 21700 High-Drain Li-ion Battery – 35A Continuous / 40A Pulse for Turbo Flashlights, RC Models & Power Tools

Unleash the Beast — 35A of Raw, Sustained Power

When your device doesn't just sip power but demands a torrent of current, the EVE 21700-40P is the answer. This high‑drain 21700 cell delivers a monstrous 35 amps continuous — enough to feed the hungriest turbo flashlights, competition‑grade RC models, and cordless power tools without breaking a sweat. It can even pulse up to 40 amps for those split‑second surges when a drill bites into hardwood or an RC car rockets off the line. With a genuine 4000mAh capacity, you get a remarkable balance of brutal discharge capability and usable runtime, making it the definitive upgrade for high‑performance applications that leave ordinary energy cells gasping for voltage.

Unprotected — Pure Power, No Compromises

Like all high‑drain cylindrical cells, the 40P is supplied as an unprotected bare cell. We intentionally omit the external protection PCB to keep the cell as short as possible (70mm flat top) and to slash internal resistance to an absurdly low level. This means more of your device's demanded current actually reaches the load, less energy is wasted as heat, and voltage sag is virtually eliminated even under extreme loads. Of course, such raw power demands responsible handling: always use a quality charger that stops at exactly 4.2V, and only install the cell in devices that feature their own built‑in low‑voltage cutoff. Every turbo flashlight, brushless RC electronic speed controller, and modern cordless tool pack already incorporates this — they were born to pair with cells like the 40P.

Three Terminal Choices — One Perfect Fit

Because no single shape fits every device, we provide three distinct positive terminal options so you can select exactly what your gear requires:

• Button Top: A raised positive nipple (~1.5mm). This locks securely into spring‑loaded battery compartments and sails through mechanical reverse‑polarity guards. Ideal for many consumer flashlights and some power tool adapters that rely on a spring‑based positive contact.

• Flat Top: A completely flush positive terminal. This is mandatory for ultra‑tight flashlight tubes, for building custom spot‑welded battery packs, and for devices with pogo‑pin or recessed flat PCB contacts. Many high‑performance lights (ZebraLight, Emisar, Noctigon, etc.) specifically require flat top cells.

• Nickel Tab: Both positive and negative ends come pre‑welded with pure nickel strips. This is the turn‑key solution for building high‑drain battery packs: 2S or 3S configurations for RC cars, 5S1P packs for cordless drills, or custom power banks. The tabs are professionally attached and ready for soldering or additional spot welding.

Where 35A Transforms Performance

Let's be specific about what 35 amps can do. In a turbo flashlight with FET driver and multiple high‑discharge LEDs, this cell holds its voltage rock‑steady — no premature step‑down, no flickering, just a blinding wall of light for as long as thermal limits allow. In a 1/10 scale RC truggy running a brushless 4‑pole motor, the 40P delivers relentless punch out of corners and strong top‑end speed throughout a 10‑minute heat. In a cordless drill or impact driver, the motor bites into steel and hardwood with authority, refusing to stall even under heavy load. The 4000mAh capacity means you don't sacrifice all runtime for current — you get a genuine balance that works in the real world. And when you need a split‑second 40A burst, the cell delivers it without voltage collapse.

Advanced INR Chemistry for Demanding Loads

The "INR" designation stands for Nickel‑Manganese‑Cobalt (NMC), a chemistry optimized for both high energy density and high discharge rates. Compared to older ICR or IMR cells, the 40P offers superior thermal stability, lower internal resistance, and a longer cycle life. Speaking of internal resistance: at ≤14mΩ, this is one of the lowest‑resistance 21700 cells on the market. At 35A, the voltage drop is only about 0.49V — meaning your device stays in regulation far longer than with a generic cell. The 40P is rated for over 500 full charge/discharge cycles with ≥70% capacity retention, so it will serve you for years of hard use. Low self‑discharge ensures it stays ready in your toolbox, pit bag, or emergency kit.

Safety Without the PCB

Despite the lack of an external protection IC, the 40P incorporates multiple passive safety layers. A PTC thermistor increases resistance if the cell overheats, limiting current and preventing thermal runaway. A resealable pressure vent in the positive cap safely releases gas if internal pressure builds to dangerous levels. A CID (Current Interrupt Device) physically disconnects the internal electrode if pressure continues to rise beyond the vent's capacity. These features provide peace of mind when the cell is used responsibly: never short‑circuit it, never expose it to fire or water, and always use a quality charger.

Key Features

• Extreme High‑Drain: 35A Continuous / 40A Pulse
  Delivers a genuine 35 amps without sag — perfect for turbo flashlights, RC racing, and cordless power tools. Pulses up to 40A for instantaneous torque bursts.

• Genuine 4000mAh Capacity
  A balanced capacity for high‑drain applications. Enough runtime for a 10‑minute RC heat, dozens of screws driven, or a full night of intermittent turbo use in a flashlight.

• Unprotected Bare Cell
  Short 70mm length fits standard 21700 tubes. Ultra‑low internal resistance ensures maximum power delivery and minimum heat. Requires a 4.2V Li‑ion charger and a device with low‑voltage cutoff.

• Three Terminal Options: Button Top, Flat Top & Nickel Tab
  Button Top for spring‑contact hosts. Flat Top for tight tubes and welded packs. Nickel Tab for ready‑to‑weld custom battery builds. Choose the exact configuration your project demands.

• Ultra‑Low Internal Resistance (≤14mΩ)
  Near‑negligible voltage drop under load. At 35A, the sag is only ~0.49V — keeping your devices at full power until the cell is nearly empty.

• Advanced INR Chemistry
  Nickel‑Manganese‑Cobalt (NMC) formulation delivers superior thermal stability, higher discharge capability, and longer cycle life than older ICR or IMR chemistries.

• 500+ Cycle Life & Low Self‑Discharge
  Recharge over 500 times with minimal capacity loss. Stores for months at 3.6–3.7V, ready for the next race day or job site.

• Multi‑Layered Passive Safety
  Built‑in PTC thermistor, resealable pressure vent, and CID provide three levels of protection against over‑temperature and over‑pressure.

• Rugged Nickel‑Plated Steel Can
  Corrosion‑resistant and impact‑resistant. Engineered to withstand the bumps, drops, and vibrations of power tools, RC vehicles, and outdoor use.

Technical Parameters

Applications

1. Turbo Flashlights & Hot‑Rod Lights
   For FET‑driven lights, multi‑emitter hot‑rods, and custom SBT90.2 builds that draw 15–35A, the 40P is the ultimate power source. It holds voltage rock‑solid, preventing early step‑down and keeping your lumens at maximum. Flat top fits ultra‑tight tubes; button top secures in spring‑loaded hosts.

2. RC Models — Cars, Trucks & Boats
   Build a 2S or 3S competition pack for 1/10 or 1/8 scale RC racing. The 35A continuous discharge feeds even the most demanding brushless motors with relentless punch. The 4000mAh capacity gives you strong runtime for qualifiers and mains. Nickel tab option simplifies pack assembly.

3. Cordless Power Tools — Rebuilds & Upgrades
   Replace worn‑out cells in drills, impact drivers, circular saws, and angle grinders. The 40P handles the 20–35A spikes that modern tools demand, keeping the motor spinning under heavy load. Use flat tops to weld into 5S1P or 5S2P configurations for 18V/20V packs.

4. High‑Power DIY Battery Packs
   Build a portable jump starter, a 12V camping battery, or a drone ground station. The low internal resistance allows efficient series connections, and the pre‑welded nickel tabs make assembly fast and reliable.

5. Vaping Mods & High‑Performance Electronics
   In regulated mods that support up to 35A, this cell delivers stable voltage for sub‑ohm tanks. Always respect Ohm's law and device ratings. Flat top fits most removable battery sleds.

6. Professional & Industrial Equipment
   Portable barcode scanners, thermal printers, medical devices, and handheld test equipment that require both high current and extended runtime benefit from the 40P's balanced performance.

FAQ

Q1: Can this battery really deliver 35A continuously? I've seen some rated at 40A.
A: Yes, 35A is the verified continuous discharge rating. The cell can handle 40A pulses (under 3 seconds). We state the honest continuous specification so you can trust what you're buying. If you need a true 40A+ continuous cell for extreme applications, we recommend the Samsung 30T or Molicel P42A.

Q2: Why is this cell unprotected? Is it safe for my flashlight or tool?
A: Removing the protection PCB keeps the cell short (70mm flat) and minimizes internal resistance, which is critical for high‑drain performance. It's completely safe when you use a quality 4.2V charger and only install it in devices with their own low‑voltage cutoff — which virtually all turbo flashlights, RC ESCs, and power tools have. The cell includes a PTC, vent, and CID for passive protection.

Q3: Which terminal should I choose — Button Top, Flat Top, or Nickel Tab?
A: Button Top for devices with spring‑loaded positive contacts. Flat Top for tight tubes and pogo‑pin/flat PCB contacts (common in enthusiast flashlights). Nickel Tab if you're building a spot‑welded pack. Check your device's manual or measure the battery compartment.

Q4: Can I use this battery in a regular EDC flashlight or headlamp?
A: Technically yes, but it's massive overkill. A regular EDC light that draws 1–3A doesn't need 35A capability, and you'd be paying for power you won't use. For those applications, a 5000mAh high‑capacity cell like the EVE 50E is a much better fit, offering longer runtime at a lower price.

Q5: How does the 40P compare to the 50E?
A: The 40P is a high‑drain cell (35A) with 4000mAh, designed for power tools, turbo lights, and RC models. The 50E is a high‑capacity cell (10A) with 5000mAh, designed for flashlights, fans, and cameras that prioritize runtime. Choose 40P for current, 50E for capacity.

Q6: Can I build a cordless drill battery with these?
A: Absolutely. The 40P is one of the best cells for rebuilding 18V/20V tool batteries. Its 35A discharge handles the high spikes of drills and impact drivers, and the 4000mAh provides decent runtime. Use flat tops or nickel tab versions for easy spot welding.

Q7: How hot does this battery get at 35A?
A: With ≤14mΩ internal resistance, heat generation is manageable. At 35A continuous, the cell temperature may reach ~75°C after a few minutes, which is within safe limits for short bursts. For sustained high‑drain use, ensure some airflow or resting periods. The PTC will limit current if it gets too hot.

Q8: Can I charge this battery at 4A?
A: Yes, the maximum charge current is 4A (1C), but for best longevity, we recommend the standard 2A (0.5C) charge. Fast charging at 4A will generate more heat and may slightly reduce overall cycle life.

Q9: How should I store this cell when not in use?
A: Keep it in a plastic case or silicone sleeve, away from metal. For storage over a month, bring the voltage to ~3.6–3.7V (about 50% charge). Check every 3 months and top up if below 3.0V. Never store fully depleted.

Q10: Is this battery safe for air travel?
A: Yes, 4000mAh × 3.7V = 14.8Wh, well under the 100Wh IATA limit. Carry it in hand luggage with terminals insulated.