18650 Batteries: Small in Size, Big in Performance

Placed on

In the world of portable energy, there is one player that quietly steals the show: the 18650 battery. This little powerhouse has a huge impact on how we use and store energy. But what makes this battery so unique? Let's take a closer look at the world of 18650 batteries and find out what makes them so special.

What is an 18650 Battery?

On first hearing, the term "18650 battery" may sound intimidating - technical, complex and for technicians only. However, in reality, the concept behind this name is astonishingly simple. The designation '18650' is a direct representation of the physical dimensions of the battery: a diameter of 18mm and a length of 65.0mm. The '0' at the end indicates that the battery has a cylindrical shape.

These compact and powerful energy packs are of the lithium-ion type. Lithium-ion technology is widely regarded as a revolutionary breakthrough in energy storage, thanks to the high energy density, long life and minimal self-discharge of the batteries.

The 18650 batteries are characterized by their versatility and have firmly established themselves in a wide range of applications. Thus, they have become an essential part of laptops, reliably supporting the computing power of these devices. But their applications extend far beyond portable computers.

In the world of flashlights, 18650 batteries are a popular choice due to their endurance and high capacity, resulting in longer burn times. Electric vehicles, from e-bikes to fully fledged electric cars, have also benefited from the benefits of 18650 batteries. Their high energy density makes them ideal for applications where space and weight are important considerations.

While they may be unknown to the average consumer, 18650 batteries have quietly become indispensable in our everyday technology. They are the silent heroes, unobtrusive but crucial, in supporting our digital and increasingly electric lifestyle."

3.7V 18650 2600mAh Battery - RechargeableThis 3.7V Li-ion battery (18650) with a capacity of 2600mAh is rechargeable and can therefore be used up to 500 times. No longer available € 5,75

History of the 18650 Battery

The 18650 batteries were first introduced in the early 1990s and were one of the first lithium-ion batteries on the market. They have since revolutionized the world of rechargeable batteries. They were originally designed for use in laptops, but their high energy density and long life have seen them used in an increasing number of devices over the years.

Technical specifications

With an average capacity of 1800mAh to 3500mAh, these batteries can provide energy for much longer than their smaller counterparts. In addition, they have a high discharge rate, which means that they can deliver large amounts of energy in a short time.

When we compare 18650 batteries with other types of batteries, such as the common AA or AAA batteries, there are a few clear differences. First, the capacity of 18650 batteries is much higher than most other batteries. This means they can last longer before needing to be recharged or replaced. In addition, 18650 batteries are rechargeable, meaning they can be reused rather than thrown away after a single use.

18650 batteries are rated at 3.7V, although this may vary depending on the exact chemistry of the battery. They can be charged to a voltage of about 4.2V and have a minimum discharge voltage of about 2.5V. It is important to note that deep discharging the battery below this minimum voltage can shorten the battery life and in some cases even lead to irreversible damage.

Safe use of 18650 Batteries with ESP32 and Arduino

Using 18650 batteries with microcontrollers like the ESP32 and Arduino can easily make your projects completely wireless. However, given the different and variable voltage of 18650 batteries (average 3.7V), caution is advised when connecting to these devices.

For devices such as the ESP32, which normally operate at 3.3V, it may be necessary to use a voltage regulator to ensure that the voltage of the 18650 batteries remains at a safe level for the ESP32. When connecting an 18650 battery to an ESP32-c3 or an ESP32s, always check that the specifications of your specific ESP32 module allow an input voltage of 3.7V.

For 5V devices like the Arduino , you can use a step-up voltage regulator to bring the voltage from the 18650 battery to a safe value for the Arduino . Note, if you use an Arduino wifi module, the power requirement may be higher, so make sure your 18650 battery can provide that power.

Connecting 18650 Batteries

Connecting 18650 batteries to your electronics projects doesn't have to be complicated. One of the most important considerations when using 18650 batteries is choosing the right battery holder in combination with a voltage regulator. Fortunately, there are many modules available today that are designed with built-in 18650 battery holders, such as certain ESP32 and Arduino boards.

These modules make it easy to integrate 18650 batteries into your projects. You just need to place the battery in the holder and you're good to go. This not only simplifies mounting, but also ensures safe and reliable contact between the battery and the module.

But what if your module you're going to use doesn't have a built-in 18650 battery holder? Don't worry, we have different holders in our range. We sell a wide range of battery holders suitable for 18650 batteries. These holders are ideal for building your own custom power supplies. They are easy to connect to your electronics and provide a flexible and safe way to use your 18650 batteries.


18650 batteries have revolutionized the world of portable power, thanks to their high capacity, efficiency and versatility. They are the undisputed powerhouses that enable us to use our laptops longer, keep our electric vehicles going further, and take our DIY electronics projects to the next level.

Choosing the right 18650 battery and connecting it safely to your devices is crucial to the success of your projects. Whether you choose a module with a built-in battery holder or a separate battery holder with a carefully selected voltage regulator, you are ready to go completely wireless!

With the right knowledge, 18650 batteries are an incredibly powerful tool for everyone from hobbyists and do-it-yourselfers to industry professionals. Whether you're interested in developing your own custom power solutions, or simply looking for a better way to power your devices, 18650 batteries open up a world of possibilities.

Bee Opencircuit we are proud of our wide range of 18650 batteries, battery holders and compatible devices. We invite you to visit our online store and discover the power of 18650 batteries for yourself.

Posted by Website I am interested in electronics, programming and especially the combination between them. For Opencircuit I write blogs in which I explain how electronics and modules work.


The Netherlands Constapel
What is the difference between vt4 and vt3 with 18650 batteries?
Placed on 
Webwinkelkeur Kiyoh Trustpilot Opencircuit