Understanding Electric Bike Batteries: The Advantage of 21700 Cells

Understanding Electric Bike Batteries: The Advantage of 21700 Cells

Understanding Electric Bike Batteries: The Advantage of 21700 Cells Over 18650 Cells

Electric bike batteries are the heart of any e-bike, determining its range, performance, and longevity. Among the various battery cells used, the 21700 and 18650 are the most common. Here’s why the 21700 battery cell is increasingly becoming the preferred choice over the 18650.

The Basics of Battery Cells

  1. Size and Capacity:
    • 18650 Cell: Measures 18mm in diameter and 65mm in length, typically offering a capacity of up to 3500mAh.
    • 21700 Cell: Measures 21mm in diameter and 70mm in length, with a capacity of up to 5000mAh.

Key Advantages of 21700 Cells

  1. Higher Energy Density:

    • The 21700 cell packs more energy due to its larger size, allowing for longer rides on a single charge. This means fewer charging cycles and extended battery life.
  2. Improved Efficiency:

    • With higher capacity, fewer cells are needed to achieve the same battery pack size, reducing complexity and potential points of failure. This streamlines the design and can lead to more efficient energy use.
  3. Better Thermal Management:

    • The 21700 cells handle heat more effectively due to their larger size, which spreads heat over a greater area. This leads to improved performance and safety, especially under high loads.
  4. Longer Lifespan:

    • The enhanced thermal management and energy density contribute to a longer overall battery lifespan. Riders can expect better performance over more charge cycles compared to 18650 cells.
  5. Enhanced Performance:

    • E-bikes with 21700 battery packs often experience more consistent power delivery, which translates to smoother acceleration and better handling, especially on challenging terrains.

Did You Know?

Tesla previously used 21700 cells in their cars, benefiting from the same advantages of higher energy density, improved efficiency, and better thermal management. This technology has now been adapted for use in high-performance electric bikes.

Ampd Brothers' Commitment to Quality

At Ampd Brothers, we exclusively utilize premium Samsung 21700 cells in all our electric bikes. This ensures our bikes deliver superior range, reliability, and longevity, providing our customers with the best riding experience possible.

Practical Implications for E-Bike Riders

Switching to a 21700 battery cell in an electric bike can offer noticeable improvements in daily use. Riders can enjoy longer trips with fewer charging stops, maintain peak performance during rigorous rides, and benefit from a battery that’s designed to last longer and perform better.


The shift from 18650 to 21700 battery cells in electric bikes represents a significant leap in technology, offering enhanced energy density, efficiency, thermal management, and lifespan. For anyone considering an electric bike or looking to upgrade their battery, opting for one with 21700 cells is a wise choice for superior performance and reliability.

For more insights into the latest in electric bike technology and how to choose the best components for your ride, explore our comprehensive guides and reviews.

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