21700 vs 18650 Battery, Which One is Better?

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18650 cells stand out as one of the most widely used rechargeable lithium-ion batteries. They are readily available and come at a reasonable price. Although they offer certain advantages over the larger 21700 batteries, they might be a bit pricier than the 21700 lithium batteries.

What is 21700 battery?

A “21700 battery” is a rechargeable type of battery, specifically a lithium-ion one, that measures 21mm in diameter and 70mm in length. Initially, these batteries gained popularity in electric cars such as Tesla and electric scooters. Nowadays, they are commonly used in vaping devices and flashlights too.

What is 21700 battery?

What is the advantages of 21700 cells?

21700 cells offer several advantages that make them desirable for various applications:

What is 18650 Battery?

Higher Capacity

Generally, 21700 cells have a larger capacity compared to other lithium-ion batteries. This means they can store more energy, providing longer-lasting power.

Higher Discharge Rate

These cells often have a higher discharge rate, allowing them to deliver power more quickly. This is crucial for devices that require bursts of energy or high power output.

Improved Energy Density

The energy density of 21700 cells is often higher, meaning they can store more energy in a given volume. This is essential for applications where space is a premium, such as in electric vehicles.

Better Thermal Performance

21700 cells tend to have improved thermal performance, which means they handle heat better during charging and discharging. This can contribute to the overall safety and longevity of the battery.

Wider Range of Applications

Due to their combination of high capacity, discharge rate, and energy density, 21700 cells are versatile and find use in various devices, including electric vehicles, flashlights, and other high-performance electronics.

Tesla Usage

The adoption of 21700 cells by Tesla in their electric vehicles, like the Model 3, has brought attention to their advantages in terms of energy efficiency and performance.

It’s important to note that the specific advantages can vary between different brands and models of 21700 cells, and factors like the intended application and the particular chemistry of the battery also play a role in determining their performance.

What is 18650 Battery?

An “18650 battery” is a kind of rechargeable lithium-ion battery that’s 18mm in diameter and 65mm in length. Thanks to their impressive capacity and ability to deliver power quickly, these batteries are frequently found in flashlights, laptops, scooters, and other devices that need a lot of energy.

Even Tesla Model S cars use 18650 cells, highlighting their versatility. Originally, these batteries gained attention in electric cars and scooters, especially in Tesla vehicles.

21700 vs 18650 lithium battery in size, capacity, voltage and more

The 21700 and 18650 battery are both rechargeable lithium-ion batteries commonly used in various electronic devices.

21700 vs 18650 Battery


21700 is a bit bigger (21mm70mm), while 18650 is smaller (18mm65mm).


Both batteries use lithium-ion technology for power.


They operate at about 3.6 – 3.7 volts.


Both can be charged with a standard lithium-ion battery charger.


They can provide quick power for various devices.


They power things like laptops, flashlights, and electric vehicles.


21700 stores more energy than 18650.


21700 is great for high-powered devices, 18650 has less capacity and is not ideal for high-powered gadgets.

How many types of 21700 cells are available in the market?

The market offers a variety of 21700 cells, with different types and specifications. Major manufacturers, including Samsung, LG, Panasonic/Sanyo, and Tesla, produce various models catering to diverse applications. Each brand and model may have specific characteristics, such as capacity and discharge rate, making them suitable for different uses. Reedway 21700 batttery cells are available now:

JOINSUN 21700 Series Cells

Can you charge 21700 batteries in a 18650 charger?

No, it is not recommended to charge 21700 batteries in a charger designed for 18650 batteries. While both batteries use similar lithium-ion technology, the 21700 battery is larger and has a higher capacity and discharge rate than the 18650 battery. This means that the charging current and voltage required for the 21700 battery may be different from what the 18650 charger is designed to provide.

Using an incompatible charger may result in undercharging, overcharging, or overheating the battery, which can cause damage to the battery or even lead to safety hazards. It is important to use a charger that is specifically designed for the type of battery you are using to ensure proper charging and to avoid any potential safety risks. Therefore, it is recommended to use a charger that is specifically designed for charging 21700 batteries.

Does 21700 last longer than 18650?

Yes, in general, a 21700 battery can last longer than an 18650 battery due to its larger size and higher capacity. The larger size of the 21700 battery allows for a higher energy density, which means that it can store more energy than the 18650 battery.

The typical capacity range for a 21700 battery is 3000 – 5000mAh, while the typical capacity range for an 18650 battery is 1500 – 3500mAh. This means that a fully charged 21700 battery can provide more energy and run for a longer period than a fully charged 18650 battery, all other factors being equal.

However, it’s important to note that the actual performance and runtime of a battery depend on various factors, such as the device it’s used in, the discharge rate, and the temperature. In some cases, an 18650 battery may perform better than a 21700 battery in certain applications. Ultimately, the choice between a 21700 and an 18650 battery will depend on the specific requirements and needs of the device or application.

How many types of 18650 battery cells are available in the market?

There are numerous types and models of 18650 cells available in the market, produced by various manufacturers. the lifespan of most NCM 18650 cells are roughly 300-1000 times. Different brands offer 18650 cells with varying specifications, capacities, discharge rates, and chemistries to meet the diverse needs of applications such as laptops, flashlights, vaping devices, and electric vehicles.

21700 vs 18650 batteries in cost

The cost of 21700 and 18650 batteries can vary depending on a few factors, including the brand, the capacity, and where you purchase them. For example, a Samsung INR21700-30T battery might cost around $8.99, while a LG MJ1 18650 battery could cost around $4.49. However, Redway can always provide amazing prices. (Check Redway 21700 battery wholesale price)

Generally, 21700 batteries tend to be more expensive than 18650 batteries. This is because they have a higher capacity and can power devices for longer periods of time. Additionally, 21700 batteries are less common than 18650 batteries, so they may be harder to find and more expensive.

When choosing a battery for your device, it’s important to consider the cost as well as the capacity. A more expensive battery might last longer than a cheaper one, but it also might not fit your budget. Ultimately, it’s up to you to decide which battery is right for your needs.

Which one is better? 21700 vs 18650 battery

Choosing between a 21700 and 18650 battery depends on specific needs. 21700 batteries offer higher capacity, discharge rates, and energy density, making them suitable for applications requiring more power. However, their larger size may limit compatibility. On the other hand, 18650 batteries are smaller, lighter, and widely available, making them versatile, but with lower capacity. Consider your device’s space constraints, power requirements, and compatibility when deciding between the two. There isn’t a universal “better” choice; the decision hinges on the unique demands of the application at hand.

Who produce 21700 and 18650 cells?

18650 cells are produced by several companies around the world. Some of the major manufacturers of 18650 cells include Panasonic, LG Chem, Samsung SDI, Sony, etc. There are many other companies that produce 18650 cells as well, including Chinese manufacture Redway Battery. It’s important to choose a reputable manufacturer when purchasing lithium-ion batteries to ensure quality and safety.

How to choose the correct lithium battery for your electric mobility?

Choosing the correct lithium battery for your electric mobility device requires careful consideration of several factors, including:

  1. Voltage: The battery’s power level needs to match what your device needs. Check your device’s info or ask the maker about the right power range.
  2. Capacity: The battery’s size should give you enough power for how far you need to go. Think about how much distance you want to cover on one charge. The battery’s size, weight, and cost can change based on this.
  3. Discharge Rate: Your battery should let out power fast enough for your device. For speedy devices like e-bikes, you might need a battery that can give a lot of power quickly, especially for going uphill or speeding up.
  4. Size and Weight: Your battery should fit well and not make your device too heavy or off-balance. It should snugly fit where the battery goes in your device.
  5. Safety: Think about safety when you’re choosing a lithium battery. Look for batteries that have safety features built-in, like stopping charging when full or protecting from a sudden power drain.
  6. Compatibility: Your battery should work with your device’s charging system. Some devices need a special kind of battery or charger, so check before buying.
  7. Budget: Consider how much you want to spend. Bigger and stronger batteries usually cost more, so find the best one that fits your needs without breaking the bank.

If you have no idea or need more professional battery solutions, please feel free to contact the engineer team of Redway Battery.


Are 21700 batteries better than 18650? In many aspects, 21700 batteries offer advantages over 18650 batteries, including higher energy density, increased capacity, and improved performance in terms of power output and cycle life.

What are the advantages of 21700 battery? Some advantages of 21700 batteries include higher energy density, increased capacity, improved thermal performance, and better overall efficiency compared to 18650 batteries.

Does Tesla use 21700 batteries? Yes, Tesla uses 21700 battery cells manufactured by Panasonic in some of its electric vehicle models, including the Model 3 and Model Y.

How long do 21700 batteries last? The lifespan of a 21700 battery can vary depending on factors such as usage, charging habits, and environmental conditions. Generally, well-maintained 21700 batteries can last several hundred charge-discharge cycles or more.

Why are 21700 batteries cheaper than 18650? The cost of 21700 batteries may be lower than 18650 batteries due to advancements in manufacturing technology, economies of scale, and improvements in production efficiency.

Can I replace 18650 with 21700? In some cases, it may be possible to replace 18650 batteries with 21700 batteries, depending on the compatibility of the device and the specific requirements of the application. However, it’s essential to ensure that the device can accommodate the larger size and different voltage of 21700 batteries.

What is the most powerful 21700 battery? The most powerful 21700 batteries typically have high capacities and discharge rates, with brands like Samsung, Sony, and LG offering some of the best-performing options in terms of power output and energy storage.

How many 21700 cells are in a Tesla? Tesla electric vehicles typically use thousands of 21700 battery cells arranged in battery packs to provide the required power and energy storage capacity for driving.

How much is a 21700 vs 18650 battery? The price of 21700 batteries may vary depending on factors such as brand, capacity, and quantity purchased. Generally, 21700 batteries may be slightly more expensive than 18650 batteries due to their larger size and higher capacity.

What is the difference between 18650 and 21700 pros and cons? Some pros of 21700 batteries compared to 18650 batteries include higher energy density, increased capacity, improved thermal performance, and better overall efficiency. Cons may include slightly higher cost and compatibility issues with devices designed for 18650 batteries.

What is the maximum amp of 21700? The maximum continuous discharge current of a 21700 battery can vary depending on the specific brand and model, but some high-performance options can support continuous discharge currents of up to 30 amps or more.

What are the best 21700 cells? Some of the best-performing 21700 battery cells are manufactured by companies like Samsung, Sony, and LG, offering high capacities, excellent discharge rates, and reliable performance for various applications.

Why is 18650 so popular? 18650 batteries gained popularity due to their compact size, high energy density, and versatility, making them suitable for a wide range of applications, including flashlights, laptops, and electric vehicles.

Which 18650 is the most powerful? The most powerful 18650 batteries are typically those with high capacities and discharge rates, produced by reputable manufacturers like Panasonic, Samsung, Sony, and LG.

What brand of 18650 does Tesla use? Tesla initially used Panasonic 18650 battery cells in its earlier electric vehicle models, such as the Model S and Model X.

Does Tesla use 18650 cells? While Tesla initially used Panasonic 18650 battery cells in some of its electric vehicles, newer models, such as the Model 3 and Model Y, use larger 21700 battery cells manufactured by Panasonic.

How many 18650 batteries does a Tesla have? Older Tesla models, such as the Model S and Model X, used thousands of Panasonic 18650 battery cells arranged in battery packs to provide the required power and energy storage capacity for driving.

Can I use double AA batteries instead of 18650? While it may be possible to use AA batteries in place of 18650 batteries in some devices using adapters or modifications, it’s essential to consider factors such as voltage, capacity, and compatibility to ensure safe and proper operation.

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