We now have a truly massive number of devices that charge via USB, including smartphones, tablets, wireless earphones, and laptops. Along with this, the types of USB chargers have diversified to a surprising degree.
With so many technical terms appearing—such as output wattage, port types, and fast charging standards—many people likely find themselves wondering, “Which one should I choose?”
Ms. GadgetThere are so many types that I find it difficult and confusing to know what to choose.
Mr. GadgetDon’t worry, once you know the basics, you can choose without making a mistake!
Choosing a charger with the wrong knowledge doesn’t just mean slow charging; it can also prevent you from taking full advantage of your device’s performance, or in the worst case, lead to safety issues such as device malfunction or overheating.
Choosing a charger arbitrarily with the mindset that “anything is fine as long as it charges” is actually a very dangerous practice.
In this article, we will clear up these questions and anxieties about choosing a USB charger and explain carefully, in a way that is easy to understand even for beginners, how to confidently find the optimal unit for the devices you own.
Be sure to read through to the end to make your digital life more comfortable and safe.
Written by: Mr. Gadget
- Studied under Masatoshi Ono, a million-selling singer with experience performing at Kohaku Uta Gassen
- Supervision experience for Ameba Choice and web media Picky’s
- Individual member of the Word-of-Mouth Marketing Association
I look forward to sharing this with you!
What is a USB Charger?
A USB charger is an “AC adapter” that takes electricity from a household electrical outlet (AC 100V) and converts it into direct current (DC) that can be supplied to charge devices such as smartphones. In the past, a charger was always included in the box when purchasing a smartphone, but significant changes have occurred in recent years.
The Arrival of the Smartphone Era Without Included Chargers
Starting with the iPhone 12 series and continuing with many Android smartphones, chargers are no longer included in the box, citing environmental considerations (such as reducing electronic waste).
In other words, even if you purchase a new smartphone, you need to prepare a separate charger yourself.
Even those who have previously just used whatever included charger came with their device must now understand how to choose one and find a product that suits their own devices.
Risks of Incorrect Selection
Choosing incorrectly can lead to the following risks:
- Extremely long charging times (insufficient output)
- Accelerated battery degradation (low-quality power supply)
- Danger of overheating or fire (inferior products failing to meet safety standards)
Far from being “penny-wise and pound-foolish,” you could end up breaking valuable devices worth tens of thousands to hundreds of thousands of yen. Having the mindset of “choosing a proper product” is extremely important.
Essential Knowledge for Choosing a USB Charger
To help you choose the optimal unit, we will explain “5 technical terms” that you must know when looking at product packages and specification tables.
Understanding these elements will point you toward the best charger for your devices.
We will explain the details of “Output (Wattage)”, “Fast Charging Standards”, “Port Types and Quantity”, and “Size and Shape” with specific focus on each point.
① Output (Wattage): The Figure That Determines Charging Speed
“W” (watts) indicates the amount of electrical power the charger can supply at one time. The higher this number, the faster you can charge your device.
| Example of Device to Charge | Estimated Required Output (Guide) | Example of Fast Charging Standard |
|---|---|---|
| Smartphone | 18W to 35W | PD, QC |
| Tablet | 30W to 45W | PD, QC |
| Laptop | 30W to 100W | PD |
Ms. GadgetMy smartphone says it supports 25W, but is it okay to use a 30W charger?
Mr. GadgetChargers with an output higher than the wattage required by the device can be used without issues, and the charging speed will be limited to the device’s supported upper limit.
Additionally, if you want to charge multiple devices simultaneously, you must choose a charger with a total output equal to or greater than the sum of the watts required by each connected device.
However, as we will discuss in detail in the port section, please note that when multiple ports are used, power is distributed to each port, which may reduce the maximum output of each individual port.
By choosing a charger with appropriate output, you can shorten charging time and reduce daily stress.
② Fast Charging Standards (PD, PPS, QC)
To maximize a charger’s performance beyond simply having a high wattage, confirming support for “fast charging standards” is extremely important.
Representative standards include “USB Power Delivery (USB PD)” and “Quick Charge (QC)“.
| USB PD (Power Delivery) | [Current Standard] A universal standard supporting up to 240W. Adopted by many devices such as iPhone, iPad, MacBook, and Pixel. If in doubt, choosing “PD compatible” is foolproof. |
|---|---|
| PPS (Programmable Power Supply) | [PD Option] Technology that finely adjusts voltage and current to suppress heat generation. Essential for “super-fast charging” on Android smartphones such as the Galaxy. |
| Quick Charge (QC) | [Older Standard] Qualcomm’s proprietary standard. Primarily used in Android, but many current versions are compatible with PD. |
Also, please understand that to perform fast charging, the device, the USB charger, and the USB cable must all support the same fast charging standard.
Here is a summary table of the features of PD and QC.
| PD Version | Release Date | Max Power | Max Voltage | Key Features |
|---|---|---|---|---|
| 1.0 | July 2012 | 100W | 20V | Exchanges 5 fixed power profiles |
| 2.0 | August 2014 | 100W | 20V | Up to 100W power supply and video/data over a single cable via USB-C Alternate Mode, automatic negotiation of optimal power between devices, and backward compatibility with older standards |
| 3.0 | 2015–2017 | 100W | 20V | Fine voltage adjustment in 20 mV increments and reduced heat generation via PPS*1 |
| 3.1 | 2021 | 240W | 48V | Introduces EPR (Extended Power Range) mode enabling power delivery exceeding 100W, bidirectional power, and hub communication (optional) |
*1 PPS (Programmable Power Supply) = A mechanism that efficiently charges by finely adjusting voltage and current to match the device’s demands.
| QC Version | Release Date | Max Power | Voltage Range | Key Features | USB PD Compatibility |
|---|---|---|---|---|---|
| 1.0 | 2013 | 10W | Up to 6.3V | Automatically determines optimal current for each smartphone | None |
| 2.0 | 2014 | 18W (A) / 60W (B) | 5V/9V/12V/20V | Supports 3-stage voltage switching and dual charging*2 | None |
| 3.0 | 2015–2016 | 36W | 3.2 to 20V (in 200mV increments) | Suppresses heat generation by finely varying voltage | None |
| 4 / 4+ | 2016–2017 | 100W | QC: 3.6 to 20V / PD: 5V, 9V, PPS | PD Compatible | Yes |
| 5 | 2020 | Over 100W | 3.3V to 20V+ | USB PD PPS compatible, enhanced thermal management, full backward compatibility | Yes (via PPS) |
*2 Dual Charging = Simultaneously charges using two independent power circuits to reduce time.
Ms. GadgetI often hear about fast charging, but how can I check if my smartphone supports it?
Mr. GadgetChecking the product specifications in the instruction manual or on the manufacturer’s official website is the most reliable way.
By understanding the fast charging standards your device supports, you can select the optimal combination of charger and cable, significantly reducing charging time.
③ Port Shape and Quantity (Type-C / Type-A)
When choosing a USB charger, “port types and quantity” greatly affect usability.
Main shapes include USB Type-A, USB Type-C, and Lightning.
Mr. GadgetiPhones from the 15 onwards use USB Type-C as well!
It is important to check whether your device’s terminal matches one of these three shapes or another shape such as Micro USB Type-B.
Take a good look at your device’s terminal so you don’t end up saying, “I want to charge it, but the terminal is different!”
④ GaN (Gallium Nitride): Miniaturization Technology
“GaN” is a next-generation semiconductor material. Because it generates less heat and has better energy efficiency compared to conventional silicon materials, it has successfully reduced the size of chargers dramatically (down to the size of a golf ball).
Mr. GadgetFor portability, models adopting GaN are overwhelmingly recommended. Please choose a USB charger of the optimal size and shape, taking into account your installation space and other factors.
Choosing a charger with an easy-to-use shape makes charging even more convenient.
⑤ PSE Mark: Proof of Safety
The “PSE mark” is a state-defined proof of safety standards, indicating that the product satisfies the technical criteria stipulated by Japan’s Electrical Appliance and Material Safety Law.
Products lacking this mark are not permitted to be sold or used within Japan.
To protect your precious devices and prevent unexpected troubles such as fires and accidents, always choose products bearing the PSE mark when purchasing a USB charger.
How to Choose a USB Charger
Based on these fundamental knowledge points, we will explain the steps for actually selecting the unit that is perfect for you. Choosing with “rationale” rather than “just guessing” prevents post-purchase regrets like “it’s slower than I thought” or “it didn’t work.” Let’s check along the following 6 steps.
STEP 1: Check Your Devices
Check the types of equipment you want to charge, their connection terminals, and their supported fast charging standards. First, list all the devices you want to charge on a daily basis. The specs of the charger you should choose vary greatly depending on whether it is “just a smartphone,” “a smartphone and earphones,” or “also a laptop.”
Mr. GadgetParticularly important is whether or not you will charge a “laptop.” Unlike smartphones, they require a large amount of power, so until this is decided, you cannot proceed to the next step.
STEP 2: Required Output (Wattage)
Among your listed devices, determine the wattage to match the “device that requires the most power.” If the wattage is insufficient, charging speed will be slow, or in the worst case, charging may not be possible at all.
Ms. GadgetSince “larger covers smaller,” can I just buy one with a high wattage to be safe?
Mr. GadgetThat’s right! For example, charging a smartphone (20W) with a 65W charger is safe because it adjusts automatically. If you are unsure, choosing a higher output (the 45W to 65W class capable of charging PCs as well) offers high versatility and is recommended.
STEP 3: Match Fast Charging Standards
Check whether the device, charger, and cable support the same standards, such as PD (Power Delivery) or QC (Quick Charge). Currently, choosing products that support the global standard “USB PD (Power Delivery)” is the basic approach.
To achieve fast charging, all three of the following must support it. If even one of them does not support it, fast charging cannot be performed.
- Device (such as the smartphone itself)
- Charger (AC adapter)
- Cable
Mr. GadgetSomething easily overlooked is the “cable.” Old cables from 100-yen shops are often non-PD compatible, so please make sure to prepare a Type-C cable explicitly labeled as “PD compatible.”
Also note that even with PD compatibility, the maximum output varies depending on the version.
STEP 4: Port Types and Quantity
Consider terminal types such as USB Type-A / Type-C and the number of ports you will use simultaneously. The mainstream choice moving forward is definitely “USB Type-C.” If you are buying a new one, choose a model equipped with Type-C ports.
| Pros | Cons |
|---|---|
|
Convenient for charging a smartphone and PC simultaneously Simultaneous charging possible with 2 or more ports Reduces the number of chargers to carry when traveling |
Output per port decreases during simultaneous use Example: 65W splits into 45W + 20W Tends to be larger in size than single-port models |
When selecting a multi-port model, be sure to check the “output distribution during simultaneous use.” It defeats the purpose if you want to charge a PC and smartphone at the same time, but the output on the PC side becomes insufficient.
STEP 5: Size and Shape
Prioritize compactness for portability, or stability for stationary use. The keyword here is “GaN (Gallium Nitride).”
Ms. GadgetChargers utilizing GaN are overwhelmingly smaller and lighter than conventional products. For carrying around, you could say that “GaN-adopted” and “foldable plug type” is the only choice!
STEP 6: Safety (PSE Mark)
Finally and most importantly is safety. Be sure to check for the presence of the PSE mark, overcharge and overheat protection functions, and manufacturer reliability.
Products without the PSE mark are prohibited by law from being sold in Japan. Please be careful as parallel imports on sites like Amazon sometimes include items without the mark.
Mr. GadgetItems without a PSE mark are out of the question! Also, stop buying from unknown manufacturers!
If you check these 6 steps in order, you will definitely find the best charger for you. Precisely because it is something you use every day, please choose a unit that is safe and comfortable.
Additional Terms and Specifications to Keep in Mind
Charger Lifespan and Replacement Timing
AC adapters (chargers) also have a lifespan. Because components inside called capacitors degrade over time, the lifespan is generally said to be about 3 to 5 years.
- Becomes abnormally hot during charging
- Makes abnormal noises (a buzzing sound)
- Charging cuts out occasionally
If you experience any of these symptoms, they are precursors to failure. Rather than feeling reluctant to replace it, please buy a new one for safety’s sake.
How to Choose Reliable Manufacturers
Finally, here are the manufacturers I personally trust. These have established support structures through Japanese corporate branches and have also obtained PSE certification.
- Anker: No. 1 global market share. Extensive product lineup.
- CIO: A Japanese manufacturer. Excels in miniaturization technology and is popular on crowdfunding platforms.
- UGREEN: High cost-performance with stable quality.
- Belkin: High reliability, also sold on the official Apple website.
- Elecom / Buffalo: Japanese PC peripheral manufacturers. Offer a sense of security.
Ms. GadgetItems without a PSE mark are out of the question!
Also, stop buying from unknown manufacturers!
Final Check for Choosing the Optimal USB Charger
Reconfirming Important Points
First, let’s briefly look back at the 6 steps we have covered for choosing the optimal USB charger.
Check the types of equipment you want to charge, their connection terminals, and their supported fast charging standards.
Understand the wattage required by each device and the total output when charging multiple devices simultaneously.
Confirm whether the device, charger, and cable support the same standards, such as PD (Power Delivery) or QC (Quick Charge).
Consider terminal types like USB Type-A / Type-C and the number of ports used simultaneously. Output distribution is also a must-check.
Compactness for portability, stability for stationary use. Whether the plug is foldable is also a key point.
Always check for the PSE mark, overcharge/overheat protection features, and manufacturer reliability.
Thank you for reading until the end!
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This article was originally written in Japanese and has been translated.
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