When your device runs out of battery while you’re out, it’s really troublesome.
But, even when you try to buy one, there are so many types and technical terms that many people get lost, wondering “Which one should I choose?”
Choosing the wrong one can lead to it not working as expected, and even a risk of accidents in the worst-case scenario.
Among these, safety is the most important thing you absolutely cannot compromise on.
In this article, we’ll explain five important points to help you avoid mistakes when choosing a mobile battery, from my perspective, in an easy-to-understand way.
Specifically, we’ll look at capacity (mAh), output (W/A) and fast charging standards, and input, port type and number, size and weight, as well as the particularly important safety, in detail.
What you’ll learn in this article!
5 Points to Avoid Failure When Choosing a Mobile Battery
If you know these points, you’re sure to find the perfect mobile battery for you.
Capacity (mAh)
- Compare the capacity of the mobile battery with the capacity of the battery of the device being used: Check how many times you can charge your device.
- Check the size and weight: Consider the balance between portability and battery capacity.
- Consider the usage scenario: Choose the optimal capacity depending on whether it is for daily use, long trips, or outdoor activities.
Capacity refers to the amount of electricity that can be stored in a mobile battery, and is expressed in mAh (milliampere-hour).
The larger the mAh value, the more electricity can be stored, so you can charge smartphones multiple times.
For example, if a smartphone’s battery capacity is approximately 3000mAh to 4000mAh, a 5000mAh mobile battery can fully charge the smartphone about once, 10000mAh can charge it about twice, and 20000mAh can charge it about four times.
(However, keep in mind that there is some loss, so it is more realistic to calculate based on about 70% of the stated capacity).
| Capacity (mAh) | Main intended use | Estimated number of smartphone charges (3000-4000mAh conversion) | Tendency of size and weight |
|---|---|---|---|
| 5000 or less | Emergency use, prioritize lightweight and compact | Less than 1 time | Small and lightweight |
| 5000-10000 | Daily use for 1-2 smartphone charges, prioritize portability | About 1-2 times | Slightly small, relatively lightweight |
| 10000-20000 | Multiple smartphone charges, tablet charging | About 2-4 times | Standard size and weight |
| 20000 or more | Long trips, outdoor activities, laptop charging, disaster preparedness | 4 times or more | Large and heavy |
Ms. GadgetHow do I specifically calculate how many times I can charge my smartphone?
Mr. GadgetA realistic estimate is obtained by dividing the battery capacity of the device to be charged by about 70% of the stated capacity.
The larger the capacity, the more electricity can be stored, but the size, weight, and price also change accordingly. It is important to choose a model that balances capacity and size/weight according to your usage.
Output (W/A) and Fast Charging Standards (PD/QC, etc.)
Output refers to the amount of electricity supplied from the mobile battery to the device, and is expressed in units of W (watts) and A (amperes).
The higher the output, the faster the charging speed.
Also, PD (Power Delivery) and QC (Quick Charge) are fast charging standards that enable faster charging between compatible devices.
Mr. GadgetPD is especially important!
For example, it is convenient to have an output of at least 12W for fast charging smartphones.
If you want to charge tablets or laptops, you will need a model that supports a higher output, such as 20W, 45W, or 60W.
Mr. GadgetHigher output is often required when charging laptops.
| Example of device to be charged | Recommended output (estimate) | Example of fast charging standard |
|---|---|---|
| Smartphone | 12W～18W | PD, QC |
| Fast charging compatible smartphone | 20W～30W | PD, QC |
| Tablet | 20W～30W | PD, QC |
| Laptop | 30W～100W | PD |
USB Power Delivery (PD) version specifications
Here is a table summarizing the features of PD and QC.
| PD version | Release date | Maximum power | Maximum voltage | Main features |
|---|---|---|---|---|
| 1.0 | July 2012 | 100W | 20V | Exchange 5 fixed power profiles |
| 2.0 | August 2014 | 100W | 20V | Up to 100W power supply and USB-CAlternate Mode for video/data in one cable, automatically negotiate optimal power between devices, and compatible with older standards |
| 3.0 | 2015～2017 | 100W | 20V | PPS※1 allows for fine-grained voltage adjustment in 20mV increments, reducing heat generation |
| 3.1 | 2021 | 240W | 48V | Introduces EPR (Extended Power Range) mode to enable power supply exceeding 100W., bidirectional power, hub communication (optional) |
※1 PPS (Programmable Power Supply) = A mechanism to efficiently charge by changing the voltage and current in detail according to the requirements of the device
| QC version | Release date | Maximum power | Voltage range | Main features | Compatibility with USB PD |
|---|---|---|---|---|---|
| 1.0 | 2013 | 10W | Up to 6.3V | Automatically determines the optimal current for each smartphone | None |
| 2.0 | 2014 | 18W (A) / 60W (B) | 5V/9V/12V/20V | 3-stage voltage switching, dual charging※2 support | None |
| 3.0 | 2015～2016 | 36W | 3.2～20V (200mV increments) | Fine-grained voltage adjustment to reduce heat generation | None |
| 4 / 4+ | 2016～2017 | 100W | QC: 3.6～20V / PD: 5V, 9V, PPS | PD compatible | Yes |
| 5 | 2020 | 100W+ | 3.3V～20V+ | USB PD PPS compatible, enhanced thermal management, complete backward compatibility | Yes (via PPS) |
※2 Dual charging = Charging is accelerated by using two independent power circuits simultaneously
Ms. GadgetMake sure to check the specifications of your device to choose the right one.
Mr. GadgetThere are also wireless charging compatible mobile batteries and other standards not mentioned here, so if you want to support other standards, be sure to check them.
Also, “input”, which is often overlooked, is important for how fast the mobile battery itself charges.
The larger the input, the shorter the charging time for the battery itself.
Choosing a model with a PD or QC compatible USB Type-C port allows you to charge the battery quickly and conveniently.
Mr. GadgetIt’s a surprisingly overlooked point, but it’s important!
Ms. GadgetAlso, be sure to choose a Type-C input!
Models that still use Micro USB are a no-go!
Port Type and Number
- Need for simultaneous charging: Choose the number of ports based on how many devices you want to charge simultaneously.
- Maximum output of each port: Check if there is enough maximum output from each port for what you need.
- Performance during multiple port use: Check how the output is distributed when multiple ports are used, and whether each port provides independent maximum output.
- Compatibility with the device to be charged: Confirm the type of port required for your device (USB Type-A, USB Type-C, etc.).
The port is the terminal for connecting the device to the mobile battery.
The type of port (USB Type-A, Type-C, etc.) and the number of ports determine how many devices can be charged simultaneously.
Choose the number of ports according to how many devices you want to charge simultaneously.
For example, if you want to charge your smartphone, earphones, and portable game console at the same time, a model with at least two ports is convenient.
Currently, the most common are USB Type-A and USB Type-C ports.
USB Type-C is particularly recommended because it can be inserted in either direction and many models support high output such as PD.
| Port type | Features | Tendency of fast charging compatibility |
|---|---|---|
| USB Type-A | Compatible with many devices, existing cables can be used, widely used | Standard (low) |
| USB Type-C | Can be inserted in either direction, easy to miniaturize, easy to support high output such as PD | Fast (PD, etc.) |
| Micro USB | Used in older Android devices, tends to be phased out as the mainstream | Standard (low) |
Ms. GadgetCan having many ports charge quickly at the same time?
Mr. GadgetEven if the number of ports increases, the maximum output for each port may decrease when used simultaneously.
If multiple ports are available, the overall output may be distributed if all ports are used simultaneously, and the maximum output from each port may decrease. It is a good idea to check this point in the specifications.
It is important to choose a model with the necessary type and number of ports according to your device configuration.
Body Size and Weight
- Ease of portability: If you carry it around every day, choose a thin and lightweight model. Consider a size that is easy to put in a bag or pocket.
- Balance with capacity: High-capacity models tend to be larger and heavier. Choose a compact model with the minimum necessary capacity.
- When and where you will use it: If you will be using it for outdoor activities or long trips, it is advisable to choose a larger, more durable model even if it is a bit heavy.
The body size and weight of the mobile battery are important factors directly related to portability.
Generally, the larger the capacity, the heavier and larger it becomes.
For example, a 5000mAh class model is about the same size and weight as a smartphone, and is easy to carry in a pocket.
A 10000mAh class model is slightly thicker and heavier, but many are still easy to carry around on a daily basis.
A large-capacity model of 20000mAh or more can weigh and be about the size of a 500ml plastic bottle.
| Capacity trend | Size/weight trend | Recommended use scene |
|---|---|---|
| Small capacity | Small and lightweight | Daily carry, not getting in the way when put in a bag or pocket |
| Medium capacity | Slightly small, relatively lightweight | Balance between capacity and portability, daily use for charging smartphones multiple times |
| Large capacity | Large and heavy | Home storage, car mounting, travel, outdoor activities, laptop charging, disaster preparedness |
Ms. GadgetI want to carry it around every day, what size is recommended?
Mr. GadgetFor daily use, we recommend a 10000mAh class with a good balance of capacity and size.
If you often carry it in a bag or pocket, it is a good idea to choose a model with a good balance of capacity and size/weight.
On the other hand, if you are going to leave it at home or in your car, or if you definitely need a lot of capacity for long trips, it is a good idea to choose a large-capacity model even if it is a bit large.
Recently, many products have become smaller even with the same capacity, so be sure to check the size as well.
Most Important Safety (PSE Mark)
- Protection functions: Check if there are functions to protect the device from overcharging, over-discharging, overheating, and short circuits. These are essential for the safe use of the battery.
- Certification marks: Check if there are certification marks indicating that the product meets safety standards, such as the PSE mark (Japan), CE mark (Europe), and FCC certification (USA).
- Reliable brands: Purchase from reputable manufacturers or brands. Refer to reviews and ratings to see other users’ feedback on safety.
The most, most important thing when choosing a mobile battery is safety.
Mobile batteries sold in Japan are required to display the PSE mark, which indicates that they meet the safety standards set by the country under the Electrical Appliance and Materials Safety Law.
Everyone should be sure to choose a product with the PSE mark.
| Safety check point | Why it is important | How to check |
|---|---|---|
| Presence of PSE mark | Proof of compliance with safety standards in Japan, reduces the risk of fire accidents, etc. | Product body or package |
| Presence of protection functions such as overcharge, overdischarge, overheat, and short circuit | Prevents battery deterioration and abnormal heat generation/ignition | Product specifications, product description |
| Purchase from a reliable manufacturer/retailer | Strict quality control and expected support | Manufacturer’s official website, trusted retailers |
Ms. GadgetBesides the PSE mark, are there other ways to check safety?
Mr. GadgetHaving protection functions against overcharging and overheating, and choosing from a reliable manufacturer also contributes to safety.
Lithium-ion batteries can cause heat generation or ignition if used incorrectly or if the product has problems.
Absolutely avoid products that do not have the PSE mark or are from unknown manufacturers.
It is also important to check if there are functions to prevent overcharging, over-discharging, overheating, and short circuits.
We recommend purchasing from a reliable manufacturer.
Mr. GadgetFor your safety, be sure to check for the PSE mark.
Ms. GadgetThis is a point you absolutely cannot compromise on.
Get a Safe and Secure Mobile Battery
In this article, we explained the important points to help you avoid getting lost when choosing a mobile battery.
Especially, safety is an absolute standard to protect your digital life.
- Estimate of necessary capacity (mAh)
- Output (W/A) and fast charging standards (PD/QC) that match your device
- Size and weight you want to carry
- Type and number of ports to connect to the devices you want to charge
If you keep these points in mind, you can find a safe and secure mobile battery that is perfect for you.
Be sure to use the knowledge you learned this time to find the best one.
Frequently Asked Questions (FAQ)
- Can I bring a mobile battery on an airplane?
-
Yes, many mobile batteries can be brought on an airplane.
However, there are restrictions depending on the capacity.
It is recommended to check the specific regulations on the airline’s website in advance, as they may vary.
You cannot check it in as baggage. - How long is the lifespan of a mobile battery? What are some tips for making it last longer?
-
Lithium-ion batteries used in mobile batteries generally have a lifespan of about 300 to 500 charge cycles.
However, this is just an estimate, and it varies greatly depending on how you use and store it.
To make it last longer, it is important to avoid “overcharging” (leaving it plugged in for a long time after it is fully charged) and “over-discharging” (leaving it unused for a long time with no charge remaining).
Storing it in extremely hot or cold places will also shorten the battery life.
Avoid leaving it in direct sunlight or in a car during the summer.
It is recommended to charge and discharge it appropriately and store it in a cool place. - What is pass-through charging?
-
Pass-through charging is a function that allows you to charge your device at the same time as you charge the mobile battery from an outlet.
With this function, if you connect the mobile battery and smartphone with a cable before going to bed, both the mobile battery and smartphone will be fully charged in the morning.
However, the mobile battery itself tends to generate heat during pass-through charging, so please be careful when using it. - How long does it take to charge the mobile battery itself?
-
The time it takes to charge the mobile battery itself varies greatly depending on the battery capacity and the “input” of the mobile battery.
The larger the input wattage (W), the shorter the charging time.
For example, even a 10000mAh class mobile battery may take a whole night to charge if the input is around 5W, but most models that support PD (Power Delivery) with a high input of 18W or 30W can be charged in a few hours.
Especially when choosing a large-capacity mobile battery, checking the input performance of the battery itself is an important point for comfortable use. - What do W (watts), A (amperes), V (volts), and mAh (milliampere-hour) mean, which are often seen in the specifications of mobile batteries?
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W (watts), A (amperes), V (volts), and mAh (milliampere-hour) often listed in the specifications of mobile batteries have the following meanings:
- V (volts): Voltage. The force that pushes electricity.
- A (amperes): Current. The amount of electricity flowing.
- W (watts): Power. Calculated by multiplying voltage (V) by current (A), it is directly related to charging speed. The larger the number, the faster it charges.
- mAh (milliampere-hour): Capacity. The total amount of electricity that can be stored in the battery. The larger the number, the more devices can be charged.
For example, V is like the water pressure in a pipe, A is like the amount of water flowing, W is like the supply capacity of the pipe, and mAh is like the capacity of a water tank.
It is important to check the power (W or A) required by your device and choose a mobile battery with the appropriate specifications based on the number of charges you want (mAh). - How should I dispose of a mobile battery that is no longer working?
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Used mobile batteries contain lithium-ion batteries, which have the potential to ignite, so they cannot be disposed of as general household waste such as burnable or bulky waste.
As a safe disposal method, first cover the terminals of the battery with insulating tape to prevent short circuits.
Then, use the mobile battery collection boxes installed at electronics retailers and home centers, or dispose of them properly according to the collection methods set by your local municipality.
Recycling is also environmentally friendly and safe. We appreciate your cooperation.
Thank you for reading this article to the end!
- The prices and information of the products are as of the time of writing this article.
- We are not responsible for any inaccuracies in this information.
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