Samsung SDI INR21700-40T 4000mAh 40A 3.7V High-Drain Li-ion Battery – 10C Discharge, 8mΩ Ultra-Low IR for High-Power Tools & Drones (Flat/Button/Welded/Wired/Protected Options, 2pcs)

Product Description:
The Samsung SDI INR21700-40T is a premium-grade 21700 lithium-ion battery cell engineered for extreme high-power, high-torque applications. This 2pcs bundle delivers a true 4000mAh capacity, an impressive 40A (10C) continuous discharge current, and an ultra-low internal resistance as low as 8mΩ (flat type), providing explosive, sustained power for the most demanding devices.

Manufactured by Samsung SDI, a global leader in battery technology, the 40T cell offers a 1000+ cycle life with ≥90% capacity retention. It features a built-in safety valve with an explosion-proof design, safely venting internal gases to prevent swelling or rupture. Every single cell is individually tested and measured before shipping to ensure genuine capacity and consistent 8mΩ internal resistance.

To suit your specific project needs, we offer 5 customized options:

1. Flat Top (2pcs): Standard 21mm x 70mm flat terminal (8mΩ IR).

2. Button Top (2pcs): 21mm x 73mm with a protruding nub for recessed contacts (~12mΩ IR).

3. Spot-Welded Tabs (2pcs): Pre-welded nickel strips for easy connection (8mΩ IR).

4. Wired (Red/Black) (2pcs): Pre-soldered positive and negative wires for plug-and-play convenience (8mΩ IR).

5. Built-in Protection Board (2pcs): Includes over-charge, over-discharge, and over-current protection (5A discharge limit; size: 21.5mm x 75mm).

Key Features:

• 2pcs of Authentic Samsung SDI INR21700-40T Cells: Premium-grade, top-tier 21700 Li-ion battery.

• 4000mAh True Capacity: Provides 4000mAh of reliable energy for extended runtimes.

• 40A (10C) High Continuous Discharge: Delivers an extreme 40A power output with minimal voltage sag.

• Ultra-Low Internal Resistance (8mΩ Flat): Ensures virtually no heat generation and maximum power transfer efficiency.

• Individually Tested Before Shipping: Every cell undergoes rigorous testing to confirm 8mΩ IR and true capacity.

• 1000+ Cycle Life (≥90% Retention): Offers excellent long-term value and durability.

• Built-In Safety Valve: Explosion-proof design safely releases internal gases in extreme conditions.

• Versatile 5 Options: Choose from Flat Top, Button Top, Welded Tabs, Wired, or Protected versions.

Product Parameters (Based on Provided Specs):

• Brand: Samsung SDI

• Model: INR21700-40T

• Size: 21700

• Capacity: 4000mAh (Typical) / 3900mAh (Minimum)

• Nominal Voltage: 3.7V / 3.6V

• Full Charge Voltage: 4.2V

• Continuous Discharge Current: 40A (10C)

• Internal Resistance: 8mΩ (Flat/Welded/Wired) / ~12mΩ (Button)

• Weight: Approx. 68g

• Cycle Life: ≥ 1000 cycles (≥90% retention after 1000 cycles)

• Safety: Positive terminal safety valve, explosion-proof design

• Dimensions (Based on Variant):

  • Flat Top / Welded / Wired: 21mm (Dia) x 70mm (H)

  • Button Top: 21mm (Dia) x 73mm (H)

  • Protected Board: 21.5mm (Dia) x 75mm (H)

• Pack Quantity: 2pcs (Selectable)

Applications:

• High-Torque Cordless Power Tools: Drives heavy-duty drills, impact drivers, and saws demanding 40A burst power.

• High-Performance RC Hobbies & Drones: Sustained high-current power for high-torque RC cars and professional UAVs.

• Electric Scooters & Light EV Conversions: Reliable high-power cells for e-scooter and e-bike battery packs.

• High-Capacity Portable Power Stations: Ideal core cell for building high-power portable energy storage systems.

• Professional Automotive & Industrial Equipment: High-performance reliability for demanding industrial machinery and tools.

Frequently Asked Questions (FAQ):

Q1: What is the discharge current of this 40T battery?
A1: The Samsung 40T is rated for an impressive 40A (10C) continuous discharge current, making it one of the most powerful 21700 cells available for high-drain applications.

Q2: What is the advantage of the 8mΩ ultra-low internal resistance?
A2: 8mΩ is an exceptionally low resistance for a 21700 cell. This means the battery generates virtually no heat and loses almost no energy during 40A discharge, maximizing performance and minimizing thermal stress on your equipment.

Q3: Is every cell tested before shipping?
A3: Yes. As shown in our product images, every single cell is individually tested before shipping. We measure and confirm the internal resistance (8mΩ) and capacity to ensure you receive the genuine product you paid for.

4Q: What kind of charger should I use for this battery?
A5: You must use a charger specifically designed for 3.6V/3.7V Li-ion batteries with a 4.2V cut-off voltage. A smart charger with over-charge protection is highly recommended.