Are 26650 Batteries Actually Better Than 18650 Batteries?

Lithium-ion batteries come in all shapes and sizes. And two of the most popular formats are 18650 and 26650.

But with two very similar models on the market, a common question is: Are 26650 batteries better than 18650 batteries?

I’m going to cover that exact question in this post. Specifically, we’ll compare 18650 vs 26650 batteries across a few key factors:

18650 vs 26650 Batteries Comparison

Battery Capacity

One of the main differences between 18650 and 26650 is capacity.

Capacity refers to how much charge a battery can hold. And it’s measured in milliamp hours (mAh).

In general, 26650 batteries have a higher capacity. Most 18650 batteries range from 1,200 mAh to 3,600 mAh.

On the other hand, 26650 battery capacity starts around 2,500 mAh. And some models even go up to 5,000+ mAh.

Higher capacity = longer runtimes. So if you need a lot of juice, the 26650 is the way to go.

Battery Size

As the names suggest, 18650 and 26650 batteries have different physical sizes:

• 18650 – 18mm diameter, 65mm tall
• 26650 – 26mm diameter, 65mm tall

So the 26650 battery is 46% wider. That extra girth is what allows it to cram in more capacity.

On the flip side, the 26650 battery weighs more than the 18650. Sometimes 2-3x more.

So if size and weight matter, 18650 is better.

Discharge Rate

Next up is discharge rate or discharge current. This spec tells you how many amps a battery can handle.

Most 18650 batteries max out at around 15-20 amps of discharge current.

The 26650 battery blows past that, with discharge currents from 30-50+ amps.

Why Discharge Rate Matters

A battery’s discharge current matters because it directly impacts performance.

For something like a flashlight, you want super bright lumens on the highest setting.

To make that happen, your battery needs to supply juice at a very high rate. And the 18650 battery might struggle with that.

So for any high-drain device, the 26650’s power delivery capabilities make it a better choice.

Voltage

One area where 18650 and 26650 batteries are evenly matched is voltage.

Both battery types output between 3.6V to 3.7V fully charged. It varies a bit between specific models. But in general the voltage range is very similar.

So voltage isn’t a key factor distinguishing 18650 vs 26650.

Battery Lifespan

Next let’s look at battery lifespan, aka cycle life.

This refers to the number of charge/discharge cycles before the battery capacity fades to 70-80% of original.

Most 18650 batteries are good for 300-500 cycles. 26650 batteries though often exceed 500 cycles, some even reaching 1,000+ cycles.

So all else equal, the 26650 battery offers 2x or more lifespan.

Power Density

While we’re talking specs, power density is another one to consider.

Power density compares the battery’s energy capacity relative to its volume. Basically it tells us how much juice is packed into the available space inside the cell.

On this metric, 26650 batteries excel too. Thanks to the larger diameter, 26650 cells fit in more power-producing material.

So most 26650 cells have over 50% higher power density compared to 18650.

More energy concentrated in a given volume = better performance.

18650 vs 26650: Real-World Impact

Ok, enough spec smackdown. What do all those numbers actually translate to out in the real world?

Well in devices like high-powered flashlights, the 26650 battery runs anywhere from 50% to 100% longer on a single charge.

You also see much better runtimes from the 26650 battery in portable power stations. We’re talking 50%+ longer runtimes.

For an electric bicycle, that added juice from the 26650 battery pack could get you an extra 10-15 miles range pretty easily.

Really for any high-drain application, the performance gains of the 26650 battery stand out:

• Brighter light output
• Faster charge/discharge
• Longer runtimes per charge
• Better energy efficiency

So when you look past the specs and consider real-world usage – the 26650 battery clearly outperforms the 18650 cell.

Especially in devices demanding sustained maximum power output.

Key Differences Summary

Let’s recap the key differences between 18650 and 26650 batteries:

18650 Battery 26650 Battery
Lower capacity Higher capacity
Lower discharge rate Higher discharge rate
Smaller physical size Larger physical size
Shorter lifespan Longer lifespan
Lower power density Higher power density

18650 vs 26650: Which Battery Wins?

So are 26650 batteries better than 18650? In most cases, yes.

The 26650 battery exceeds the 18650 on capacity, discharge rate, lifespan, efficiency and power density.

Those advantages make the 26650 battery better suited for:

• High-performance flashlights
• Electric vehicles
• Solar storage systems
• Portable power stations
• Other high-drain roles

For compact electronics though like laptop batteries and slim flashlights, the 18650 form factor still makes more sense.

So both battery types have their niche. The 18650 as a lightweight all-rounder. And the 26650 as an undisputed high-drain champ.

Understand your specific power requirements. And let that guide your 18650 vs 26650 decision when selecting a battery.