Used the cells to revitalize this dewalt battery pack. It had two dead cells. Recharged the cells before soldering it together. Works flawlessly again now… :)
Key Features
- 4000mAh Nominal Capacity: High energy density for extended runtime in demanding systems.
- 35A Continuous Discharge: Engineered to support sustained high-current applications.
- 21700 Cell Format: Larger form factor improves thermal performance and efficiency.
- Flat Top Terminal: Designed for battery pack assembly and professional integration.
- Rechargeable Lithium-Ion Chemistry: Stable voltage delivery with long cycle life.
Overview
The Samsung 40T 21700 lithium-ion battery is built for high-performance applications requiring both capacity and power. Offering a 4000mAh nominal capacity with a 35A continuous discharge rating, this cell delivers reliable energy output under heavy load conditions. Its flat top construction makes it suitable for protected battery packs and advanced power assemblies.
Applications / Uses
- Electric mobility battery systems
- Power tool battery packs
- Industrial energy storage solutions
- High-output portable equipment
- Custom lithium-ion battery assemblies
SPECIFICATIONS
| Manufacturer: | Samsung SDI |
| Model: | INR21700-40T |
| Battery Size: | 21700 |
| Positive Terminal: | Flat Top |
| Nominal Capacity: | 4000mAh |
| Max Continuous Discharge: | 35A |
| Nominal Voltage: | 3.6V |
| Maximum Voltage: | 4.2V |
| Discharge Cut-Off Voltage: | 2.5V |
| Protected: | No, unprotected |
| Rechargeable: | Yes |
| Approx. Dimensions: | 21.1mm × 70.4mm |
| Approx. Weight: | 66.8g |
| Data Specification Sheet: | Samsung 40T Datasheet |
⚠ Important Safety Warnings
Improper handling or misuse of this lithium-ion battery can result in FIRE, EXPLOSION, or THERMAL RUNAWAY, causing personal injury, property damage, or death. Users must read and follow all safety guidelines before purchase and use. Click here to review the full safety guidelines.
- Critical Warning: Never carry loose batteries in your pocket, purse, or bag. Loose batteries can come into contact with metal objects like keys or coins, causing a short circuit, which may result in severe burns, fire, or explosion. Always store or transport batteries in a protective case.
- Intended Use: This battery is designed for integration into protected battery packs with a Battery Management System (BMS) or Protection Circuit Board (PCB). It is not intended for standalone use or for e-cigarettes, vaporizers, or similar devices.
-
Thermal Runaway: A chain reaction where heat from a failing battery
causes further overheating, potentially leading to fire or explosion.
- Causes: Overcharging, short circuits, physical damage, or exposure to high temperatures.
- Prevention: Use a smart charger, avoid damage, and store batteries in a cool, dry place.
- Storage & Transport: Always store batteries in protective cases to prevent accidental contact with metal objects. Never store loose batteries in pockets, purses, bags, or near conductive materials.
- Inspection: Do not use if the PVC wrapper, terminal insulator, or casing is damaged, dented, leaking, or bulging. Continued use could result in failure, fire, or explosion.
- Charging: Use a smart charger specifically designed for lithium-ion batteries and ensure the charger's voltage matches the battery's specifications. Never overcharge, over-discharge, or leave unattended while charging.
-
Prohibited Activities:
- Do not expose the battery to extreme heat, fire, or liquids.
- Do not short circuit, puncture, crush, or modify the battery.
- Do not charge or discharge beyond the manufacturer’s voltage range.
- Do not dispose of in regular trash—always recycle at approved facilities.
- Emergency Response: If a cell shows signs of thermal runaway (e.g., smoke, swelling, hissing, or heat), stop use immediately and, if it can be done safely, move it to a non-flammable surface (e.g., concrete or sand) away from combustible materials. Lithium-ion cells burn as Class B fires — use an ABC / dry-chemical fire extinguisher, or douse with large amounts of water to cool the cell and prevent the fire from spreading. Do not rely on a small spray; thorough cooling is required, and cells can reignite from residual heat, so monitor the area afterward. (Class D extinguishers are intended for lithium-metal batteries, not lithium-ion.) For any fire beyond a single small cell, evacuate and call emergency services.
Disclaimer
18650Battery.com is not responsible for any damages, injuries, or claims arising from improper use, handling, or failure to follow these safety guidelines. Lithium-ion batteries require strict adherence to all safety protocols. It is the reseller's responsibility to ensure all safety warnings and product guidelines are effectively communicated to customers. Users and resellers assume full responsibility for the safe handling, usage, and distribution of this product.
Customer Reviews
Overall rating: 4.9 / 5 from 271 reviews.
I’ve been ordering from 18650battery for years and they’ve always shipped extremely fast and at a fair rate, never an issue! The Samsung 21700 batteries are solid quality and have plenty of juice to last the whole day.
I got my7 year old DeWalt 8Ah battery working like new for a fraction of the cost.
No issue at all. Arrived in 7 days.
Great vendor to work with,price and fast delivery.Samsung is a great brand to work with.
Works perfectly in my vape machine thank you
These are by far one my personal favorite batteries. Fast shipping is also great!
I love these batteries the quality is amazing and I can have the batteries in a few mods for days the output is amazing that’s is way I have given it a 5 star rating that way I can help people choose because I only buy the best batteries I can
I love these batteries the quality is amazing and I can have the batteries in a few mods for days the output is amazing that�s is way I have given it a 5 star rating that way I can help people choose because I only buy the best batteries I can
I use 4 of these cells on a 6s mini quad to extend flight times. I am getting 13 minute cinematic flights on a quad that normally flies for 4 minutes on a 6S 1050 mah pack!
The Samsung 40T 21700 battery has been a great balance between high output and long life that meets the needs for MY application perfectly
Just fits in my pulse bf unregulated mod. Running the profile RDA with watofo mesh it lasted me almost all day. If your not pushing the amps to need a 30t then a 40t is the best out.
Love this battery. It has plenty of power for my mechmods and I also use it on my Vandy Vape pulse X :sunglasses:
Love this cell. With it's high amp rating it exhibits nearly zero battery sag under load in a regulatedvape mod. However, It can also be used as a safe, hard hitting cell in a mech mod(when used within safe limits). Gonna be hard to beat this one i think!
Great product
Exactly as I ordered and arrived within a reasonable amount of time for ground ship only lithium batteries.
Great batteries. Fast shipping.
Everything went smoothly
as described prompt shipping
Worked well
Works as adverised
Exactly what was advertised
Great price, quick ordering, and the order arrived quickly. I will purchase again.
Slow shipping this time. Not pleased. The battery is pretty good, it does what it's supposed to.
Great batteries quick delivery, Kudos..
Easy ordering and fast delivery.
Batteries look great and charged right up no problem. Very Happy with purchase,
I had a Milwaukee 18V battery with two failed cells. This product was a perfect replacement, virtually identical to the failed cells, except that they worked.
Very good batteries and fast shipping.
Product was as advertised and operated well.
It went well. The item arrived quickly and is working just perfectly.
Great battery fast shipping!
I'm satisfied with the product
Perfect fit
AAAA ++++
Great battery!
Batteries worked for a week then started to die off
Going to use in DIY power bank but threw them into some various things in the mean time. They have been very impressive so far. And to top it off they were very inexpensive when I grabbed them. Definatly going to get some more if the price stays where it is.
Fast shipping, Great price and the batteries work as advertised! THANKS!!
At least this one had a picture with that it can't be used for vapes on it and I needed it.