ZMI, one of the Xiaomi ecosystem brands, launched a car mount wireless charger on August 1st. Main selling points include 20W fast wireless charging for phones like the Xiaomi 9, easy-to-operate zinc alloy arms, as well as intuitive operation. Let’s dive into the teardown.

I Unboxing

It comes with ZMI’s minimalistic white box.

Main features: 20W max fast wireless charging, alloy arms, and intuitive operation.

Specifications ont he back.

Model: WCJ10

Input: 5V2A, 9V1.6A, 12V1.6A, 15V1.6A, 20V1.35A

Output: 20W MAX

Operating Temperature: 0℃-35℃

Diemensions: 122*91.59*87.2mm

Package contents: car mount wireless charger, car charger, clip, base with a sticker, Micro-USB cable, and user manual.

Specifications of the included car charger:

Input: 12-24V4A.

Output: 5V2A (USB1); 5V3A, 9V2A, 12V2A, 15V1.8A, 20V1.35A (USB2).

The car mount wireless charger should be connected to the red USB port to enable fast wireless charging.

The USB port 1 has normal charging speed while the red USB port 2 supports fast charging.

The base with a sticker at the bottom.

The clip.

Rear view of the car mount wireless charger. Ventilations along the edges.

On the front, a lightning bolt logo indicates the wireless charging area.

Two stands on the bottom to hold the phone.

Alloy arms in dark grey color.

Pity the input port is Micro USB instead of USB-C.

Silicone pads inside of the clamp arms ensure firm grip of the phone.

Close-up of the hinge of the alloy arm. 

Close-up of the silicone pads inside of the clamp arms.

The car mount wireless charger can be mounted to the air vent using the provided clip, or mounted to the base with a sticker at the bottom.

Top view.

Side view.

The ZMI 20W car mount wireless charger not only supports Xiaomi 20W fast wireless charging, but also support Apple 7.5W, Samsung 10W wireless charging, offering superb wireless charging compatibility.

It starts charging instantly when we put the phone inside.

There is an LED indicator at the bottom near the input port.

The arms grip the phone very firmly.

Big phones like the iPhone XS Max can also be perfectly fitted inside.

Our Samsung S10+ shows that it supports Samsung 10W wireless charging.

II Teardown

Pry open the front cover.

The middle frame is exposed with a few screws, and the main components of the wireless charging are hidden inside.

Remove the screws and remove the back cover to reveal the main parts of the product.

Main parts of the product.

Close-up of the mechanical structure with gears and spring. One end of the upper and lower springs hooks the base and the other end hooks the clamp arm.

Remove the two arms which have a serrated and spring structure. Springs are used to control the alloy clamp arms to match various widths of the mobile phones, and the serrated structure allows the product to expand.

Zinc alloy metal parts and PCBA circuit boards.

Remove the middle frame to reveal the wireless charging coil.

There are two light guides on the top of the plastic middle frame.

PCBA and wireless charging coil.

The wireless charging coil and the magnetic spacer are fixed on the zinc alloy metal plate for structural rigidity and heat dissipation.

A temperature probe is attached to the center of the coil with tapes.

There is a black shading foam between the two LED indicators.

CBB capacitor, 0.25μF.

Wireless charging controller chip with letter code MI9500, Xiaomi custom chip based on NuVolta architecture.

Another custom chip from Xiaomi with letter code MI9000, an integrated power stage for wireless charging with built-in driver and power tube. It is also based on NuVolta architecture.

Passive crystal oscillator that clocks the wireless charging controller.

MOS tube with letter code 3401.

MLCC capacitors.

All the components.

III Conclusion

The ZMI 20W car mount wireless charger not only supports Xiaomi 20W fast wireless charging, but also support Apple 7.5W, Samsung 10W wireless charging with great wireless charging compatibility. Its clever and robust alloy arms offer intuitive operation. And its minimalistic design fits perfectly into almost every car interial. However the use of Micro USB instead of USB-C is a let down.

Like many of ZMI’s power banks, the 20W car mount wireless charger utilizes Xiaomi’s custom chips for performance, efficiency, and lower costs, which further shows the talent of its engineering team.


20W max wireless charging.

Minimalistic design.

Easy operation.


Micro USB input port.

Source: chongdiantou


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