Are 18650 Batteries the Same Size as AA? A Detailed Comparison

While 18650 batteries and AA batteries may look similar at first glance, their dimensions actually differ quite significantly. In this comprehensive guide, as a professional 18650 battery manufacturer, we’ll analyze the key size differences between 18650 vs AA batteries, battery capacities, performance implications, and suitable applications for each battery type.

Are 18650 Batteries the Same Size as AA?

No, 18650 batteries are noticeably longer and wider than AA batteries. The extra size allows 18650s to pack in more power capacity.

18650 batteries measure 18mm in diameter and 65mm in length. On the other hand, a standard AA battery measures just 14mm in diameter and 50mm long. Right off the bat, you can see that 18650 batteries have a larger capacity thanks to their bigger size.

But the size difference has major impacts for performance too…

18650 vs AA Battery Sizes Broken Down

Let’s start by looking at the key size attributes of 18650 batteries vs AA batteries:

Dimension Overview

• 18650 battery: 18mm x 65mm
• AA battery: 14mm x 50mm

As you can see, 18650 batteries are noticeably wider and longer than traditional AA batteries. That little bit of extra size allows 18650 cells to pack a lot more power capacity.

Now, you might be wondering if there’s an AA-sized lithium-ion battery that has similar performance to the 18650. We’ll cover that next.

Lithium-Ion “AA” Batteries

There are actually lithium-ion batteries made to the AA battery size standard, typically called 14500 batteries.

However, these small li-ion cells still don’t match the capacity and performance of 18650 batteries. The main reason is that 14500 cells just don’t have as much physical internal space for the electrode windings that store power.

The chart below compares 18650 cells to 14500 li-ion cells:

As you can see, there’s still a sizable capacity gap between 18650’s and AA-sized li-ion batteries.

Next, we’ll look at how the size difference affects real-world battery performance.

How Battery Size Affects Performance and Applications

The dimensional differences between 18650 and AA batteries have major impacts on their suitable applications and overall performance:

Battery Capacity

Due to its larger size, a single 18650 li-ion cell provides vastly higher capacity compared to any type of AA battery:

• 18650 battery capacity: Up to 3,500 mAh
• AA alkaline battery capacity: Around 2,000-3,000 mAh
• AA NiMH rechargeable capacity: Around 1,200-1,900 mAh

Higher battery capacity means more potential runtime for devices between charges. 18650’s significant capacity advantage makes them far better suited for high-drain devices.

High Drain Capability

Besides longer runtimes, 18650 batteries also handle high discharge rates far better than AA batteries.

For example, good quality 18650 cells can maintain 10A discharge rates while high-drain AA cells struggle above 5A loads.

This superior electrical performance means 18650 lithium-ion batteries excel in devices like vapes, high-powered flashlights, or cordless power tools. AA batteries are poorly suited for those heavy current applications in comparison.

Lebensdauer des Ladezyklus

Lithium-ion batteries are much longer-lasting through regular recharge cycles compared to rechargeable AA NiMH cells:

• 18650 cycle life: Approximately 500 cycles
• AA NiMH cycle life: Around 200-300 cycles

So you’ll get more mileage long-term out of 18650 batteries through consistent recharging to power devices.

Conclusion: Key Takeaways on 18650 vs AA Batteries

While 18650 batteries and AA batteries appear visually similar, they differ substantially in their dimensions and performance capabilities:

• 18650 cells are clearly larger at 18mm x 65mm compared to AA batteries at 14mm x 50mm
• The bigger 18650 size enables over twice the capacity of AA batteries
• 18650 lithium-ion batteries massively outperform AA batteries in high-drain devices
• 18650 cells also last over twice as long through repeated recharge cycles

So in summary, 18650 batteries are the superior choice over AA batteries for high-power devices thanks to their larger size and lithium-ion chemistry advantages. Opt for AA batteries for lower-drain electronics like remote controls or clocks.