Safe for smartphones and PCs! How to choose a USB charger | How to find the best one

Smartphones, tablets, wireless earphones, notebooks, and more – the number of devices charged via USB is really increasing.
Along with that, the types of USB chargers are diversifying incredibly.
With a lot of specialized terms like output wattage and port types, many people may be wondering, “Which one should I choose?”

Choosing the wrong charger can not only result in slow charging but also prevent you from taking full advantage of your device’s performance, and in the worst-case scenario, it could lead to safety issues such as device failure or overheating.
“As long as it charges, anything is fine” – actually, choosing a charger carelessly is a very dangerous action.

This article will resolve your doubts and anxieties about choosing a USB charger and clearly and carefully explain how to confidently find the best one for your devices, even if you’re a beginner.
Please read to the end and make your digital life more comfortable and safe.

Basic knowledge for finding the optimal USB charger

Choosing a USB charger, which is essential to your digital life, is very important.

Why is choosing a charger important now? What are the risks of making the wrong choice? And what is the current situation with smartphones? We will explain the basics in an easy-to-understand manner.

Avoiding risks due to incorrect selection

If you choose the wrong USB charger, several risks may occur.
First, the most immediate risk is that charging will take a long time.
If you use a charger with an output (W) lower than what your device requires, it may take hours to fully charge, preventing you from using your device immediately.

More seriously, there is the risk of device failure or overheating.
Using a substandard or incompatible product can cause unstable voltage or current, which can overload the device, accelerate battery degradation, or damage internal circuits.

Especially, products that do not meet the Japanese Electrical Appliance and Materials Safety Law standards, meaning they do not have a PSE mark, are not guaranteed to be safe.
“You get what you pay for” – and in this case, it could mean damaging your valuable device. Therefore, it is very important to have the awareness of “choosing a good product.”

The arrival of the smartphone era without chargers

In the past, when you bought a smartphone, a charger (AC adapter) and cable were always included in the box.
However, recently, Apple has stopped including chargers with the iPhone 12 series and later, citing environmental considerations.

This means that even if you buy a new smartphone, you need to prepare a charger separately.
Those of you who have been using the included charger without thinking about it need to understand how to choose one and find a charger that suits your smartphone.

There are many high-performance and convenient products other than genuine ones, so let’s gain the correct knowledge and choose a charger with confidence.

Step 1 in choosing a USB charger: Confirming your devices

The most basic step in choosing a USB charger is to accurately know what we want to charge.
Identifying all the devices you want to charge is the first and most important step in finding the optimal charger.

It is important to check in advance what connection terminals your devices have and what fast charging standards they support.
We will explain the specific methods in the following headings.

Listing the devices to be charged

Listing the devices to be charged is an action to understand all the charging needs of your devices.
This is very useful in determining the “type” and “number” of chargers you need.

Write down all possible devices that may be charged via USB, including smartphones, tablets, notebooks, wireless earphones, smartwatches, and portable game consoles.

By specifically listing the charging devices, you can clearly imagine the type and number of chargers you need.

4 factors that determine charging performance and convenience

To choose a USB charger, it is important to check the 4 factors that determine charging performance and usability.

If you understand these factors, you will be able to see the optimal charger for your devices. “Output (W)”, “Fast charging standards”, “Port type and number”, and “Size and shape”. We will explain each point in detail so that even beginners can understand.

Output (W) – The key to charging speed

The “output (W)” of a USB charger is a factor that greatly affects charging speed.
“W (watt)” is a unit that indicates the amount of power that the charger can supply at once.

The larger this number, the faster the device can be charged.

For example, smartphones generally can be fast-charged at around 20W to 30W, but tablets require 30W or more, and notebooks with high power consumption require 45W to 100W or more.
Check the W number required by the devices you want to charge and choose a USB charger with a higher output.

Also, if you want to charge multiple devices simultaneously, you need to choose a charger with a total output greater than the sum of the W numbers required by each device.

However, as explained in the port number section, when using multiple ports, the output is distributed to each port, and the maximum output of each port may decrease.
By choosing the appropriate output charger, you can shorten the charging time and reduce stress in your daily life.

Fast charging standards – The importance of confirming compatibility (USB PD, QC, etc.)

To maximize the performance of the charger, it is very important to confirm the fast charging standards.
Fast charging standards are like agreements that allow devices and chargers to communicate and efficiently and safely supply power.

Representative standards include USB Power Delivery (USB PD) and Quick Charge (QC).

USB PD is widely used in USB Type-C ports and allows high-power charging for a wide range of devices, from smartphones to notebooks.
Quick Charge is a standard mainly adopted by Android smartphones with Qualcomm processors.

Also, to perform fast charging, all of the device, USB charger, and USB cable must support the same fast charging standard.

Standard name	Features	Main compatible device examples
USB Power Delivery (PD)	Can charge much faster than standard charging, can also charge notebooks	iPhone 8 and later, many Android smartphones, many tablets, many notebooks
Quick Charge (QC)	Can easily fast charge Android smartphones	Many Android smartphones (depending on the model), some tablets

It is very important to know which fast charging standards your devices support.
Don’t think, “I don’t care what it is, as long as it charges fast!” Please try to confirm it once.

This GaN material is more efficient and generates less heat than conventional silicon, allowing the charger body to be made smaller and lighter.
This makes it easier to carry high-output chargers, reducing the burden of carrying a large AC adapter for a notebook PC, and improving convenience.

By understanding these factors, you will be able to see the optimal charger for your devices.

Ports – Selecting the type (Type-A/C) and number

When choosing a USB charger, the “port type and number” greatly affect usability.
The main shapes are USB Type-A, USB Type-C, and Lightning.

USB Type-A is a traditional, square-shaped standard terminal that is often found in older devices and chargers (primarily output only).

Lightning is Apple’s proprietary terminal, mainly used for iPhone and certain iPad input terminals.

On the other hand, USB Type-C is the latest oval-shaped terminal that can be smoothly inserted without worrying about the orientation, and is widely adopted by the latest smartphones, tablets, and notebooks. (often used for both input and output)

It is important to check whether your devices have one of these three terminals, or other shapes such as Micro USB Type-B.

Terminal name	Brief description of shape	Main features	Input/Output	Main compatible device examples
USB Type-A	Square	Traditional standard terminal	Output only	Old chargers, PC ports
USB Type-C	Oval shape with symmetrical top and bottom	Can be inserted without worrying about orientation, supports high-speed data transfer and high output (USB PD)	Both input and output	Latest smartphones, tablets, notebooks, earphone cases, etc.
Lightning	Apple’s proprietary slim shape	Apple’s proprietary terminal	Basic input	iPhone (before 14), some iPads, AirPods cases, etc.
Micro USB Type-B	Small shape resembling a flattened trapezoid	Standard terminal for older small devices, still in use in some cases	Input only	Old Android smartphones, mobile batteries, Bluetooth speakers, etc.

Checking this terminal is essential to avoid “I want to charge it, but the terminal is different!”
Please be sure to check the terminal of your devices so that you don’t make a mistake.

Confirming the type of terminal and the number of ports you need will help you choose a charger that is easy to use.

Size and shape – Portability and installation location

The “size and shape” of a USB charger is a point to consider depending on how you use it.

If you often carry it around, it is convenient to choose a compact and lightweight model that does not get in the way in your bag or pocket.
A type with a foldable plug is even more portable, as it prevents the plug from damaging other items in your bag and makes it easier to carry.

On the other hand, if you use it fixed in a place such as your home or office, you can also choose a model with multiple ports or a design that blends in with the installation location, even if it is a little larger.

This GaN material is more efficient and generates less heat than conventional silicon, allowing the charger body to be made smaller and lighter.
This makes it easier to carry high-output chargers, reducing the burden of carrying a large AC adapter for a notebook PC, and improving convenience.

Considering your main use scene (whether you carry it around or not), and the space in the installation location, choose the optimal size and shape of USB charger.
Choosing a charger with a shape that is easy to use will make charging even more comfortable.

Essential checks for safe and secure use

When choosing a USB charger, charging performance and usability are important, but the most important thing is to check for safety to protect your devices and yourself.

Confirming the safety standard “PSE mark”

The “PSE mark” is a proof of safety standards stipulated by the Japanese Electrical Appliance and Materials Safety Law.
This mark indicates that the product meets the technical standards stipulated by the country.

It is mandatory to display this mark on electrical products sold or used in Japan, especially on AC adapters such as USB chargers.
This mark is displayed on the product body or package.

PSE mark display	Safety	Legality in Japan
Displayed	Safety has been confirmed based on the law	Sale and use are permitted
Not displayed (including similar marks)	Safety has not been confirmed based on the law	Sale and use are not permitted

To protect your valuable devices and prevent unexpected troubles such as fire or accidents, be sure to choose a product with the PSE mark when purchasing a USB charger.

Check for protective functions such as overcharge and overheat prevention

USB chargers have various protective functions to protect the device and the charger itself from trouble during charging.
It is also essential to check whether these functions are equipped.

Representative protective functions include overcharge prevention, which automatically stops charging when the device’s battery is fully charged, overheat protection, which stops charging when the charger or device temperature becomes abnormally high, short-circuit protection, which prevents circuit shorts, and overcurrent protection, which prevents abnormally high current flow.

Protective function	Function
Overcharge prevention	Suppresses battery degradation
Overheat protection	Prevents fire and equipment damage
Short-circuit protection	Prevents equipment damage due to shorting
Overcurrent protection	Protects equipment from abnormal current

To maintain a safe charging environment and use the USB charger safely and for a long time, it is important to check whether these protective functions are described in the product specifications.

Points to select products from reliable manufacturers

To choose a safe product from the many USB chargers available, it is also a very effective point to choose a product from a reliable manufacturer.
Manufacturer selection greatly affects the reliability of product quality and safety.

Reliable manufacturers set strict safety standards from the product development stage and thoroughly conduct safety tests based on the law.
They reliably obtain necessary safety certifications such as the PSE mark and disclose that information.

Also, detailed specifications and safety functions related to the product, and a support system for when problems occur are often prepared.

Checkpoints for reliable manufacturers	Content
Safety certification status	Whether or not it has acquired and displayed safety certifications stipulated by the country, such as the PSE mark
Product information details	Whether or not output specifications, compatible standards, and safety functions are clearly disclosed
Customer support	Whether or not there is an inquiry window and a warranty system, and whether or not prompt response can be expected
Market evaluation and track record	Whether or not there is a long sales track record and high evaluation from other users (word-of-mouth, reviews, etc.)

Instead of jumping on cheap products with unknown origins, choosing products from manufacturers that are clearly committed to safety and have earned trust from many users is a smart choice to ensure safe and comfortable charging in the long run.

Final check for choosing the optimal USB charger

Based on what you have learned in the previous steps, here are the points you must check in the end.
The most important thing I want to tell you is “safety” and “whether it matches your usage scene”.

Here, we will briefly review the 6 steps of important points and explain how to make a final decision based on your usage scene.

Please do not skip this final check to safely and comfortably charge your valuable devices.

Important points review

First, let’s review the 6 steps we’ve taken to choose the optimal USB charger.

By keeping these 6 points in mind, you will greatly increase your chances of finding the optimal USB charger.
In particular, it is important to prioritize checking for the PSE mark and protective functions related to safety.

By understanding these factors and making a final decision based on your specific “I want to use it like this” image, you can find a charger that is comfortable and long-lasting.

Frequently Asked Questions (FAQ)

Is choosing a wireless charger different from choosing a wired charger?

Yes, the points to consider when choosing a wireless charger are slightly different from those when choosing a wired charger.
When choosing a wireless charger, first check whether your smartphone supports the international standard “Qi (Chi).”
Wired chargers mainly focus on output wattage and fast charging standard compatibility, while wireless chargers need to consider whether it is a pad type to place your smartphone on or a stand type to hold it up, and whether it can charge multiple devices simultaneously (e.g., “2 in 1”).
Charging speed tends to be slower than with wired charging, but the latest standard-compliant products can charge at high speed.
Also, be careful as some cases may prevent charging.

How long can a USB charger be used? Are there any signs of its lifespan?

The lifespan of a USB charger generally ranges from 3 to 5 years, depending on the product quality, frequency of use, and storage environment.
If the charger is deteriorating, you may notice that charging takes longer than before, the charger becomes abnormally hot during charging, or strange noises come from the body.
If you notice any of these abnormalities, we recommend replacing it with a new charger for safety.
Continuing to use it against your better judgment may lead to failure or unexpected accidents.

Are there any other safety certifications besides the PSE mark?

The PSE mark is the most important safety standard proof in Japan for selling and using electrical products.
However, there are various other safety certifications around the world.
For example, the CE mark is required for distribution mainly in the EU (European Union) and indicates compliance with safety standards.
The UL certification is a standard set by the American Insurance Safety Laboratory and is given to products that have passed very strict tests.
Products with these overseas certifications can also be said to meet a certain level of safety.
To use USB chargers safely in Japan, be sure to first check for the PSE mark.

The article says that cables are also important. What are the points to consider when choosing a cable?

Yes, as mentioned briefly in the article, choosing a charging cable is just as important as choosing a USB charger to maximize performance.
Especially when fast charging, the charger, cable, and device must all support the same fast charging standard (e.g., Power Delivery).
The cable also has specifications such as “〇〇W compatible” and “〇〇A compatible” listed on it, so it is important to choose a cable with specifications that match the power required by your charger and device.
If you use a cable that is not compatible, you may not be able to achieve the original charging speed even if you choose a high-output charger.

What is the best way to choose a USB charger for travel and business trips?

When considering carrying it around for travel and business trips, portability is the most important thing.
Choose a compact and lightweight model that does not get in the way in your bag.
A model with a plug that can be folded into the body is even more convenient, as it prevents the plug from damaging other items in your bag.
Also, if you often carry multiple devices such as smartphones and tablets, choosing a model with multiple USB ports will allow you to charge them simultaneously and use your time effectively.
However, models with multiple ports tend to be larger than single-port models, so consider the balance with portability.

I have multiple chargers. Is it okay to use any of them?

It is generally okay to use your multiple USB chargers in combination with different devices and cables.
However, it is important to understand the “output wattage,” “compatible fast charging standards,” and “port type” of each charger.
It is no problem to use a charger with an output higher than the wattage required by the device, but using a charger with a significantly lower output will take a long time to charge.
Also, as explained in the article, it is important to use products that have the PSE mark and meet safety standards.
If it is safe, you can use it in combination with the device.

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