How to Choose a Mobile Battery and 10 Recommended Models Based on Actual Measurement Data

A portable battery pack essential for charging smartphones, tablets, and laptops on the go. Various products are available from manufacturers like Anker, Elecom, CIO, UGREEN, offering a wide range of options in capacity, charging speed, and size. Deciding which model to choose can be challenging.

In this article, we thoroughly compare 10 carefully selected mobile batteries, from the latest products by popular brands to top sellers on Amazon, Rakuten Ichiba, and Yahoo! Shopping. We evaluate five key points: actual capacity, portability, fast charging performance, and more, to help you find the perfect one for your usage scene.

Five Key Points for Mobile Battery Evaluation

We’ve organized the items you should check before purchasing:

• Reliability of actual capacity: discrepancy between listed capacity and usable capacity
• Ease of portability: balance of thickness and size
• Charging speed for smartphones: actual maximum output
• Charging speed of the device itself: maximum input capacity
• Wireless compatibility: support for fast wireless charging

【For those prioritizing slim and compact design】

SMARTCOBY Pro SLIM CABLE (CIO) - Highest rating 4.6 points

Features a slim design that easily fits in your pocket alongside your smartphone. Built-in USB Type-C cable eliminates the need to prepare a separate cable.

Actual measurement shows a capacity ratio of 75.98%, very close to the stated value, ensuring reliable charging for your expected number of times. Only 1.8cm thick and with an area of 63.77cm², its remarkably compact size is ideal for daily carry.

With a maximum actual output of 39W and input of 35W, charging your smartphone and the power bank itself is smooth. Perfect for quick top-ups before heading out.

Price: 5,980 yen (as of 2026/01/15)

SMARTCOBY Pro SLIM (CIO) - Rated 4.54 points

Despite a capacity of 10,000mAh, it’s only 16mm thick. Textured surface makes it resistant to scratches, with durability suitable for daily use.

Capacity ratio is 69.47%, supporting fast charging with a maximum actual output of 38W. Recharging the device itself is quick with a maximum input of 35W. Reliable for situations where you forget to charge your phone before going out.

Equipped with three USB-C ports for simultaneous charging of multiple devices. A well-balanced choice for portability and practicality.

Price: 4,818 yen (as of 2026/01/15)

【For those prioritizing high-speed charging】

SMARTCOBY TRIO (CIO) - Rated 4.59 points

Achieves a large capacity of 20,000mAh with a high actual capacity ratio of 75.23%. Features two USB Type-C ports and one USB-A port, enabling simultaneous charging of smartphones, laptops, and earphones.

High actual maximum output of 71W and input of 67W characterize this model. Even during busy mornings, multiple devices can be quickly fully charged.

Thick at 3.0cm but with an area of 65.68cm², it’s compact and easy to store in a bag. A top candidate for those who prioritize fast charging.

Price: 6,970 yen (as of 2026/01/15)

EC-C44LBK Mobile Battery (Elecom) - Rated 4.51 points

Features three ports: two Type-C and one Type-A, compatible with a wide range of devices from smartphones to laptops. Includes a display to check remaining battery level in real-time.

Capacity ratio is 78.20%, maximum actual output 67W, and input also 67W, enabling fast charging and recharging. Suitable for frequent charging needs on the go.

At 3.1cm thick and 78.00cm² in area, it’s a size that fits easily into bags. A reliable partner for business trips and travel.

Price: 6,999 yen (as of 2026/01/15)

Prime Power Bank (9600mAh, 65W, Fusion) (Anker) - Rated 4.46 points

A unique design combining a USB charger and power bank. Features foldable plug for direct wall charging.

Capacity ratio is 81.31%, with a maximum actual output of 67W, offering excellent fast charging performance. Quick to recharge itself, ready for sudden outings.

Small area of 49.81cm² allows it to be stored compactly in bags or pouches. Ideal for those who want both high performance and convenience.

Price: 14,990 yen (as of 2026/01/15)

【Multi-function and balanced features】

Uno Built-in Cable Mobile Battery (UGREEN) - Rated 4.53 points

Achieves a high capacity ratio of 82.26%, with integrated USB Type-C for three simultaneous charges. Real-time charging status can be checked via display, adding convenience.

Maximum actual output of 35W and input of 30W enable efficient charging of both the device and the power bank. Thickness of 2.0cm and area of 80.68cm² make it compact, supporting about two full charges of 10,000mAh capacity.

An optimal choice for daily use, from commuting to business trips.

Price: Not listed

Zolo Power Bank (10000mAh, 30W, MagGo) (Anker) - Rated 4.52 points

Extremely high capacity ratio of 86.69%. Features the latest MagSafe-compatible wireless charging with magnetic fixation for iPhone, enabling wireless charging.

Wired charging maxes out at 33W, with an input of 20W. Wireless charging speed is 7.5W, which is slower, but convenient when not in a rush.

Made with silicone material to prevent device scratches, especially recommended for iPhone users.

Price: 5,990 yen (as of 2026/01/15)

MagFlow PB773 (UGREEN) - Rated 4.48 points

Supports Qi2 standard wireless charging with 25W output, approaching wired charging speeds. Built-in USB Type-C cable allows smart switching between wired and wireless charging.

Maximum actual output of 36W, input of 30W, capacity ratio 73.66%. Good performance overall. Thickness of 2.1cm and area of 77.87cm² make it highly portable.

Ideal for those seeking fast charging and portability.

Price: 6,825 yen (as of 2026/01/15)

SMARTCOBY Ex03 SLIM PLUG ＆ CABLE (CIO) - Rated 4.48 points

Includes built-in USB Type-C cable and foldable AC plug. A 3-in-1 design with pass-through function for simultaneous charging of smartphone and device.

Capacity ratio is 82.28%, maximum actual output 36W. Thickness of 2.2cm and area of 73.21cm² ensure portability.

A perfect choice for those who want to combine AC charger and power bank functions in one device.

Price: 5,780 yen (as of 2026/01/15)

Power Bank (10000mAh, Fusion, Built-In USB-C Cable) (Anker) - Rated 4.47 points

Features a 3-in-1 design with built-in USB Type-C cable and AC adapter. Capacity ratio is 83.73%, demonstrating high reliability.

Maximum actual output of 35W, quick recharging of the device itself. Suitable for long trips and business travel.

Compact with a thickness of 3.1cm and an area of 55.34cm², easy to carry in bags or pouches.

Price: 7,990 yen (as of 2026/01/15)

How to Choose the Perfect Mobile Battery for You

Summarizing the features of these 10 models, your selection criteria should be:

For those who want daily portability: Slim models like SMARTCOBY Pro SLIM CABLE and Pro SLIM, under 2cm thick, are ideal. They fit comfortably in pockets without stress.

For those needing to charge both smartphone and laptop on the go: High-output models like SMARTCOBY TRIO and Elecom EC-C44LBK (67W or more) are recommended. They enable fast charging of multiple devices simultaneously.

For those who want one device for both charger and power bank: Models with AC plugs like Ex03 SLIM PLUG ＆ CABLE and Power Bank Fusion are convenient. You can charge without worrying about outlets.

For those seeking the latest wireless charging features: Consider Qi2-compatible models like MagFlow PB773 and Zolo Power Bank MagGo. Enjoy a comfortable wireless charging experience.

The best mobile battery choice depends on your lifestyle and priorities. Use the evaluation data provided here to find the one that suits you perfectly.