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Samsung 40T Li-Ion
samsung 21700 battery
10/10 icon-question
  • Lithium-ion
  • 4,000 mah capacity
  • 35 amp continuous discharge

Samsung is well known for its excellent products, including its batteries. These lithium-ion batteries provide high capacity and discharg...

BestFire 21700 Battery
BestFire 21700 battery
  • 4,000 mah capacity
  • Li-HP
  • 60 Amp continuous discharge current
Imren 21700
Imren 21700 Battery
  • 4,000 mah capacity
  • 35 amp continuous discharge rate
  • 3.6 to 3.6 nominal voltage

What Does 21700 Mean for a Battery?

21700 is the number of the battery’s dimensions. The dimensions are 21 mm in diameter and 70 mm in length. They are given this number based on the dimensions because it makes it easier for customers to find and identify the battery.

Here are 6 Best 21700 Batteries

#1 Samsung 40T Li-Ion

The Best 21700?


Samsung is well known for its excellent products, including its batteries. These lithium-ion batteries provide high capacity and discharging/drain capabilities, meaning absolute 4,000 mah capacity and constant and accurate 35 amp discharge. Moreover, it can do all these things without reaching excessive temperatures.

#2 BestFire 21700 Battery

Affordable With High Capacity

BMR 21700


  • 4,000 mah capacity
  • Li-HP
  • 60 Amp continuous discharge current
  • 40 Amp max discharge current
  • 3.7 volts

These high-capacity batteries have 4,000 mah and charge very quickly compared to similar cells. Additionally, they are affordably priced at $7.99 per cell. Best Fire batteries are perfect for vapers looking for mid-range price batteries that can provide several hours of steady vaping time and less waiting between recharging.

#3 Imren 21700

Two-Pack Batteries

Flat Top

The Imren 21700 is a monster of a battery. It provides a high amount of power and steady output throughout the day, even when the vape is set to high wattage. So again, here is another perfect example of a battery that is ideal for high-wattage box mods and rebuildable atomizers. Better yet, they come in packs of two for $22.

#4 Imalent 21700

4,000 mah


  • 4,000 mah capacity
  • Lithium-ion
  • Warranty protected
  • 3.7 volts

This 21700 Li-ion battery may be expensive compared to others on this list, but the price is worth it. In addition, they last a long time and provide lots of vaping between recharging. Those attributes are not surprising considering they are 4,000 mah batteries.

What really makes these batteries stand out is that FastTech covers them with a solid warranty. They can be returned for a refund within 45 days or a replacement within six months.

#5 iJoy 21700 Batteries

Affordable and Powerful

Nominal Capacity:
3750 mAh
Nominal Voltage:
3.7 V
Continuous Discharge Maximum:
24 A
Rated Max Pulse:
40 A


  • 3.7 V nominal voltage
  • Maximum continuous discharge of 24 amps
  • Rated for 40 amp maximum pulse

The iJoy battery is a high discharge INR flat top battery that is rated at 3.750 mAh. It is rated for 40 amps, produces 3.7 volts, and has a 24 amp continuous maximum discharge. The biggest benefit of purchasing this battery is its affordability. It has a lower cost than most of the same batteries. This battery is recommended for use in regulated box mods that can handle 70 watts per cell.

#6 Golisi S35 IMR 21700

Long-Lasting and Durable

21 mm x 7 mm
Constant Charge:
Nominal Voltage:
Charging Cut Off Voltage:


  • Overcharge and over-discharge protection
  • Rechargeable
  • Safety tested
  • 3.750 mAh capacity

The Golisi S35 is a high capacity and performance battery that has 3.750 mAh capacity and is fully rechargeable. It is not as powerful as the Samsung 40T but is suitable for devices that can run up to 90 watts. It works well with regulated mods that require single or double batteries. With its high discharge current and 40 amp maximum output, it is quickly becoming one of the top telling 21700s on the market. Each battery can last 800 charges before needing to be replaced, and they have been certified at UL1643 standard. They also contain internal protection sheets to prevent them from overcharge and excessive discharge.

Battery Capacity Price
#5 Samsung 40T 4000mAh $8,99
#2 BestFire 21700 Battery 4,000 mah $7,99
#3 Imren 21700 Battery 4000mAh $22,00
#4 Imalent 21700 Battery 4000mAh $18,84
#5 iJoy 21700 Battery 3750mAh $6.95
#6 Golisi S35 IMR 3750 mAh $24.95

What Are the Advantages of 21700 Batteries?

The advantage of 21700 batteries vs the 18650 battery is that they last longer than 18650s or integrated batteries when used at high wattages. Another advantage over integrated batteries is that they can be replaced when no longer able to hold a charge. Integrated batteries cannot be replaced.

Which Are the Best 21700 Batteries for Vaping?

Deciding which are the best 21700 batteries is not an easy task because “best” is highly subjective. Everyone is looking for something different. Some people want high-end batteries that can work for over a day on high wattages, while others are fine with using lower-priced batteries either because they are on a budget, or they do not want to spend a lot of money on cells when they plan on vaping on low to medium wattage levels.

All of these batteries were excellent, and they will benefit vapers of all types.

How We Picked the Best 21700 Batteries

The Golisi S35 IMR 21700 may be the most expensive battery, but there are several reasons why it outranks the other batteries.

First off, in the long run, it is not all that expensive. The battery can last up to 800 cycles, which is more than a lot of other batteries can offer. Cheap batteries might look inexpensive when looking at the price tag alone, but if they are good for only a few cycles, the cost starts to add up.

Another reason why we picked it is that it is powerful. Again, not as powerful as the Samsung 40T, but it can handle up to 90 watts, and it offers good battery life.

What Brand Is the Best Lithium-Ion 21700 Battery?

Brandwise, the best battery has to go to Golisi for the reasons listed above. It is a power-efficient battery that is incredibly long-lasting. It can also handle vaping at high wattages while still providing plenty of time for vaping.

Samsung is another brand worth considering as a source for lithium-ion 21700s. Samsung is well-known for its dependable electronics; that is why they are an established name in the vaping industry. Plus, it is power efficient and is guaranteed to last at least a day on heavy vaping.

What Are the Safety Requirements for 21700 Batteries?

There are several precautions to take when handling batteries.

  1. First, do not use any that have torn wraps or look damaged.
  2. Other signs of damage are changes in color and disfiguration. Do not use them if they show any of these signs.
  3. Another thing to be aware of is not to use them for devices with which they are not compatible.
  4. Finally, if the battery gets hot in the vape, discontinue using it until it cools down.

The Competition

21700 vs. 18650 Batteries

The 21700 and the 18650 batteries have their respective advantages, but there are more benefits to using the 21700. The main reason to use the 21700s is the amount of power they deliver.

Most 18650 batteries are rated between 1.500 and 3.000 mAh, but the 21700s are rated for 3.000 mAh and higher. 21700s will run much longer than the 18650 batteries.

21700 vs. 20700 Batteries

The difference is one millimeter, and that is not supposed to be a sarcastic joke. The amps and mAh capacity of a battery varies depending on what is inside. Since the best 21700 batteries are a bit larger, there is more space inside to achieve higher mAh capacity or amps, but not both.

Check the specifications for each battery to get a good idea of how well they will operate in a mod. Both of these cells perform well, so most people will likely not notice much of a difference between them.

Frequently Asked Questions About the Best 21700 Batteries

What Is the Most Powerful and Best 21700 Vape Battery?

It is difficult to say which is the most powerful because they all have the same capacity. But the most dependable is probably Samsung’s. They perform at a high level without overheating and last a long time.

How Long Should a 21700 Battery Last?

It is difficult to say because every battery is different. But over time, batteries oxidize and degrade, so they cannot be changed infinitely. However, 21700s rank among the longest-lasting on the market. They can be charged up to 2,000 times, depending on the battery.

How Long Does It Take to Charge a 21700 Battery?

The average charge time is four hours, but it depends on the battery and the 21700 battery charger being used.

Will a 21700 Battery Fit in a 20700 Mod?

Yes, some mods can operate on both lithium-ion batteries and even with a 18650. Examples are the asMODus Amighty, the Smok Mag Grip, and the Dovpo Topside Lite.

How Long Does It Take to Charge the Best 21700 Batteries?

Each battery and charger is different. To figure out how long it takes for a battery to charge, determine the reserve capacity of the battery, and multiply it by 0.6.

How Do You Change a 21700 Battery Wraps?

Remove the old wrap and then slide on the new wrap. Then, use a heat gun or hair dryer to secure the new wrap into place.

How Many Amps Are in a 21700 Battery?

Each battery has a different amp level — the batteries in this list range from 20 to 40 amps.

How Many Volts Does a 21700 Battery for Mech Mod Devices Require?

Most of these batteries have 3.7 volts of nominal voltage. Read the specs for each battery, and check the specifications of the mod before buying batteries.

How Low Can You Build With a 21700 Battery?

To determine how low you can build, use Ohm’s Law for mechanical mods and Watt’s Law for regulated mods. Plug the values into the formulas for these laws, and you will get an answer.

Where Can I Find Battery Chargers That Works With an iJoy 20700?

Chargers that work with iJoy 20700s are widely available online. To make sure the charger is working correctly with the battery, check the temperature of the cell and the charger to make sure they are not too hot.

What Is the Continuous Output on an iJoy 21700 Battery?

The continuous output of an iJoy 21700 is 24 amps

What Is the C Rating of a 21700 Battery?

Each cell will have a different C rating. Use the formula C Rate(mah/1,000) = Continuous Discharge Amperage to determine the rating.

What Vape Coil Should Be Used for the Best 21700 Batteries?

The vape coil depends on the preference of the user. Read the directions for the mod to determine which materials work best for your mod.

How Can I Spot a 30T 21700 Battery?

30T 21700 batteries are widespread. Look at the product description on the package or online to determine whether they are 30T.

How Can I Spot a 30T 21700 Battery?

30T 21700 batteries are widespread. Look at the product description on the package or online to determine whether they are 30T.

How to Spot a Fake Samsung 21700 Battery?

To spot a fake battery, whether it is a 21700, 20700, or a 18650, check the label, contact, and overall appearance of the battery. Buyers who are worried about getting duped should buy their products from a physical store.

How Do I Know If My 21700 Battery Cycle Is Done?

Eventually, the life of the battery will decrease to such an extent that charging it is no longer feasible. When this happens, replace the battery.

Should I Buy a 21700 Battery Case?

It is not necessary but recommended. Keeping them in a case placed in a secure location will prevent the cells from being damaged due to exposure.

Final Thoughts about the 21700 Battery

Lithium-ion 21700 batteries are worth purchasing over cells like the 18650. There are a lot of good brands available, and using them will allow for more vaping time than one would get from a 18650. The best ones to get are Golisi and Samsung in terms of economy and performance. The price of these batteries is quite high, but there are cheaper options out there if the shopper looks hard enough. Cells like the MXJO are some of the most inexpensive batteries on the market, costing only eight dollars per battery.

If you are a fan of what we think are the best 21700 batteries, please give us your input. If there are any batteries or chargers out there that are high performers and we neglected to mention them, please talk about them in the commenting section.

Published: March 27, 2020 Updated: May 30, 2022

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