Unleash Raw Power
Unleash raw power with the 2Pack Samsung 40T 21700 Battery (Model: INR21700-40T). Designed for the most demanding high-drain applications, this 21700 lithium-ion cell delivers a solid 4000mAh capacity combined with an extreme 35A continuous discharge (up to 60A pulse). Whether you are building a heavy-duty power tool battery pack, upgrading a high-performance e-bike for steep climbs, or powering a sub-ohm mod, the Samsung 40T provides the explosive current and reliable stability you need, without overheating or excessive voltage sag. This listing includes two individual cells (not pre-assembled), offering the ultimate high-power solution for DIY enthusiasts and professionals alike. The 2-pack provides excellent value, giving you the flexibility to build a 2S series pack for higher voltage, a 1S2P parallel pack for increased capacity, or replace worn-out cells in pairs.
Key Features
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Extreme 35A Continuous Discharge
Built for high-power demands. Delivers massive current output consistently under heavy loads, making it ideal for the most power-hungry devices. Supports up to 60A pulse discharge for short bursts of maximum power. -
Solid 4000mAh Capacity
Offers a healthy 4000mAh capacity while maintaining its incredible high-drain capability, providing a practical balance between runtime and raw output. -
Ultra-Low Internal Resistance
Engineered for minimal energy loss during high-current discharge, generating less heat and ensuring maximum power delivery to your device. -
Authentic Samsung Quality
Premium-grade INR21700-40T cells. Genuine Samsung manufacturing guarantees exceptional cycle life, safety certifications, and consistent voltage stability under extreme loads. -
Flat Top Design
Standard flat top configuration, compatible with most battery holders, spring-loaded contacts, and DIY battery pack builds. -
2-Pack Value
Supplied as two individual cells, allowing you to build a 2S series pack (7.2V), a 1S2P parallel pack (8000mAh), or replace worn-out cells in pairs for balanced performance. -
High-Power Specialized
Specifically optimized for high-drain devices like power tools, high-performance e-bikes, and advanced electronic mods, where other cells would struggle.
Technical Parameters
| Parameter | Value |
|---|---|
| Brand & Model | Samsung INR21700-40T |
| Battery Type | Lithium-Ion (Li-Ion) |
| Size | 21700 (Diameter 21mm, Height 70mm) |
| Capacity | 4000mAh (Minimum 3900mAh) |
| Nominal Voltage | 3.6V |
| Full Charge Voltage | 4.2V |
| Cut-off Voltage | 2.5V |
| Continuous Discharge Current | 35A |
| Pulse Discharge Current | Up to 60A (not for continuous use) |
| Internal Resistance | ~10-12mΩ (Typical) |
| Positive Terminal | Flat Top |
| Protection Circuit | No (Unprotected Flat Top Cell) |
| Operating Temperature | -20°C to 60°C |
| Quantity in Package | 2 Pcs (2Pack) |
Applications
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High-Performance Power Tools
Upgrading cordless drills, impact wrenches, angle grinders, and chainsaws to handle the toughest jobs without bogging down. Two cells can power smaller tools or be used in a larger pack. -
Heavy-Duty Electric Bikes (E-Bikes)
Building or upgrading battery packs for high-torque motors, steep terrain riding, and demanding off-road e-bike applications. Two cells are a great start for a custom pack. -
High-Performance RC Models
Powering 1/8th or 1/10th scale buggies/truggies, large drones, and other RC vehicles requiring brutal current spikes. -
High-Drain Tactical Flashlights
Fueling high-lumen searchlights and tactical flashlights that demand massive current for ultra-bright output. Many tactical lights use two 21700 cells. -
Custom DIY Battery Packs
Building 2S, 3S, 4S, or larger high-power packs for robotics, e-skateboards, or portable heavy-duty tools.
FAQ
Q1: Does "2Pack" mean it's a 2S battery pack assembled together?
A: No. "2Pack" means you will receive two separate individual cells. You will need to assemble them in series (for 7.2V), parallel (for 8000mAh), or a specific configuration based on your device's requirements.
Q2: What is the difference between Samsung 40T, 50E, and 50S?
A: The 40T is the high-power specialist. It sacrifices some capacity (4000mAh vs 5000mAh) to achieve an exceptional 35A continuous discharge, far exceeding both the 50E (9.8A) and the 50S (25A). Choose the 40T for maximum power output applications like heavy power tools, high-performance e-bikes, or sub-ohm mods.
Model Comparison Table
| Model | Capacity | Continuous Discharge | Best For |
|---|---|---|---|
| 40T | 4000mAh | 35A | Maximum power (power tools, heavy e-bikes) |
| 50E | 5000mAh | 9.8A | Long runtime (flashlights, camping) |
| 50S | 5000mAh | 25A | Balanced (e-bikes, medium power tools) |
Q3: Can I use these two cells to build a battery pack for my E-Bike?
A: A single 3.6V cell (or two cells) is not enough for an e-bike (which typically requires 36V, 48V, or 52V). Two cells can be combined in series to create a 7.2V pack, which is suitable for small devices like some flashlights or RC models. For an e-bike, you need many more cells wired in series. The 40T is an excellent choice for high-performance e-bike packs, but always consult a professional if you are unsure about building a pack.
Q4: Does this battery have a protection circuit (PCB/BMS) built-in?
A: No. The Samsung 40T is an unprotected flat-top cell. It relies on the external device or a BMS (Battery Management System) to handle overcharge, over-discharge, and short-circuit protection.
Q5: What charger should I use?
A: Use a dedicated intelligent Li-Ion charger designed for 3.6V/4.2V cells. Ensure the charger supports the correct voltage for your specific pack setup (e.g., 1S charger for single cells, 2S charger for 2 cells in series, etc.).
Q6: How do I identify positive and negative terminals?
A: The flat top (the side with the Samsung logo and model number) is the Positive (+) terminal. The bottom (the side with the shiny metal casing and a slight indentation) is the Negative (-) terminal.
