Aug 09, 2026 10:00:00

Review of the 'SMARTCOBY Pro SLIM SS,' a compact yet high-capacity semi-solid-state mobile battery that can charge up to three devices simultaneously.

With summer here and hot days continuing, there have been reports of mobile batteries and handheld fans catching fire on trains and in stations, and the problem has become so serious that

Tokyu Corporation has requested that passengers refrain from using mobile batteries on their trains . The ' SMARTCOBY Pro SLIM SS ' is a semi-solid mobile battery that has succeeded in reducing the risk of such fires. It is a 'semi-solid battery' that enhances safety by making the liquid electrolyte of conventional batteries into a gel, and not only is it less likely to catch fire, but it is also compact yet has a large capacity of 10,000mAh. I was able to get my hands on the 'SMARTCOBY Pro SLIM SS' and put it to the test.

SMARTCOBY Pro SLIM SS | CIO Co., Ltd. Official Website - Charger & Mobile Battery Manufacturer
https://connectinternationalone.co.jp/cioproduct/mobilebattery/smartcoby/cio-mb35w2c1a-ssa10k-s/

◆Unboxing & Photo Review
The packaging looks like this, and it features purple, which is the corporate color of the CIO.

The contents, from left to right, are a charging cable (USB-C to USB-C), the main unit, and various documents including the instruction manual.

The package also includes a document titled 'About Semi-Solid-State Mobile Batteries.' CIO prioritizes the experience of 'being able to use it with peace of mind now' by using safer materials and technologies that can be adopted, and as a result, has come to develop semi-solid-state batteries that are safer than conventional liquid electrolyte batteries. Since there is no unified definition of semi-solid-state batteries, CIO has formulated its own requirements and definitions for structure (NovaCore C2) and control (NovaSafety S2), and releases products that meet these requirements as semi-solid-state batteries.

The details of the structure (NovaCore C2) and control (NovaSafety S2) defined by the CIO are as follows.

NovaCore C2
NovaCore C2 is a core design level that meets CIO's unique design standards regarding internal structure, including clearance (expansion margin), compartmentation (cell partitioning), flame retardancy, and heat dissipation, in addition to employing semi-solid cells from a Tier 1 battery manufacturer with a proven track record in the smartphone field. The temperature of the core semi-solid cell itself is designed to remain below 55 degrees Celsius.

NovaSafety S2
NovaSafety S2 is a safety control function that prevents excessive heat generation by constantly monitoring the internal temperature of the battery and automatically controlling the output when the temperature is high. Although not visible from the outside, all of this is controlled by CIO's proprietary firmware and is based on a design philosophy that ensures a 'safe operating temperature range.' In actual use, the parts that are touched by hand are designed to stay below a maximum temperature of 42 degrees Celsius.

The main unit looks like this, and the surface has a textured finish that makes scratches less noticeable.

Here's what it looks like next to an iPhone 15 Pro , which measures 159.9mm in height and 76.7mm in width. Its dimensions are approximately 98.3mm x 66.8mm x 16mm, and it weighs approximately 187g.

Back side

The top surface has two USB-C ports and one USB-A port. Both USB-C ports support charging the device's battery, but the USB-A port only supports output.

Bottom

Left side

There's a battery level indicator button on the right side.

When you press the battery level indicator button, the battery level indicator LED on the upper right of the device will display the remaining battery level (%) as shown below.

When charging only one device using the SMARTCOBY Pro SLIM SS, the maximum output of the USB-C port is 35W, and the maximum output of the USB-A port is 22.5W.

When charging two devices simultaneously, the combined output from both ports is limited to a maximum of 30W.

Even when charging three devices simultaneously, the combined output from all three ports is limited to a maximum of 30W.

◆I tried fully charging the SMARTCOBY Pro SLIM SS from a completely dead battery state.
First, drain the battery of the SMARTCOBY Pro SLIM SS to zero.

The SMARTCOBY Pro SLIM SS supports charging at up to 35W. Therefore, I tried charging the device's battery using

the CIO NovaPort SLIM DUOII charger, which has a maximum output of 45W, and the charging cable included with the SMARTCOBY Pro SLIM SS.

When charging, the SMARTCOBY Pro SLIM SS only displays a blinking LED indicator, as shown below; the battery percentage is not displayed.

So, to check the battery level, I unplugged the charging cable and pressed the battery level indicator button. After 5 minutes of charging, the battery level had reached 8%.

After 30 minutes of charging, the battery level reached 42%.

It charged to 78% in one hour.

And, we successfully achieved a full charge in 1 hour and 20 minutes from the start of charging.

◆I tried charging my iPhone with the SMARTCOBY Pro SLIM SS.
Next, we'll try charging an iPhone 15 Pro with zero battery remaining using a fully charged SMARTCOBY Pro SLIM SS. The iPhone 15 Pro's battery capacity is 3274mAh.