Xiaomi Mi 9 is the first device to support Qi wireless energy recharge technology. For many users, switching to this format of interaction with the gadget is a pleasant discovery, eliminating the need to constantly connect the cable. However, immediately after purchase, owners often face the question of where the switch is to activate this feature.
In fact, classic wireless charging doesn't require manually switching on the settings menu, because it works on the principle of induction. Just put the phone on a compatible platform, and the process will begin automatically. The opposite is true of the reverse charging function, which allows the device to act as a power bank for other gadgets, and this mode requires activation through the system menu.
In this article, we will discuss both use cases in detail, how to position the phone properly on the base, how to activate the power distribution mode, and what sound signals can be adjusted for comfortable use, and will also address security and compatibility issues with various accessories.
Principle of operation and activation of energy intake
The main mode, in which your Xiaomi Mi 9 receives power from the external base, works completely automatically. There is no separate switch on the MIUI operating system, since the power controller constantly scans for the presence of an electromagnetic field. Once the coil in the back of the smartphone picks up the signal, the current transfer process begins.
The only thing that you need to be aware of is the system's response to the connection. By default, the smartphone emits a characteristic sound and shows animations on the screen. If you want to change the behavior of the device when you set it to base, you need to go to the settings. Open the Settings menu, then select the Battery section and find the Wireless Charging Settings.
There are important options available that affect the user experience: You can turn off the audio if you use your phone in a quiet environment, such as at night in the bedroom, and the “Charge only at night” feature is available, which limits the current speed at certain hours to reduce the heat and noise of fans (if they are in the base).
⚠️ Warning: Make sure there are no metal objects between the back of the smartphone and the surface of the charging pad.The presence of coins, keys or cases with metal inserts can cause overheating and damage to the induction coil.
For optimal power transfer speed, the center of the coil on the back of the phone must match the center of the base as closely as possible. In the Mi 9, the coil is located at the top of the body, closer to the Xiaomi logo, rather than strictly in the center. This is an important nuance that beginners often miss when trying to put the phone exactly in the middle of a round platform.
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Use cases no more than 3 mm thick. Too thick silicone or the presence of metal plates for car holders of magnetic type block the induction and can lead to a charging error.
Reverse (reverse) charging settings
The situation changes dramatically when you need to use the Xiaomi Mi 9 as a power source for other devices.The reverse charging function does not activate on its own to avoid wasting battery power.
There are two main ways to start power distribution mode. The first is through the quick access panel. Swipe from top to bottom to open the "Stork," and find the icon with the battery and arrow. If you can't see this shortcut, click on the edit button (usually a pencil or three dots) and drag the icon "Reverse wireless charging" into the active area.
The second way is through system settings, and the algorithm of actions is as follows:
- 🔋 Go to the main menu Settings of your device.
- ⚡ Select the Battery section (or click on the percentage charge at the top).
- 🔄 Find the Reverse Wireless Charging Switch and activate it.
- 📱 Apply a compatible device with the back cover to the center of the back of your phone.
Once the mode is activated, a special icon will appear on the screen indicating readiness for energy transfer, which is a normal physical phenomenon associated with losses in energy conversion, but temperature control is still necessary.
☑️ Check before starting reverse charging
Technical specifications and compatibility
The 2019 flagship supports the Qi standard, which is universal for most modern gadgets.However, the rate of energy replenishment depends heavily on the adapter used and the charging station itself.The smartphone is capable of taking up to 20 watts when using Xiaomi's branded accessories, but with conventional bases, the speed will be limited to the standard 5-10 watts.
To activate a top speed of 20 watts, you need to meet several conditions at once. First, you need an original power supply with support for Quick Charge 3.0 or higher. Second, the charging base itself must support the proprietary Xiaomi protocol. When using third-party devices with a capacity of more than 10 watts, you probably won’t get there, but it won’t hurt the phone.
Below is a table of compatibility and expected speeds for different use cases:
| Type of device | Max. Reception power. | Required adapter | Features |
|---|---|---|---|
| Xiaomi Mi 9 (reception) | 20 W. | Xiaomi 27W / QC 3.0+ | A firm base is required |
| iPhone 8-X (receive) | 7.5 Watts | Any 18 watts+ | Standard Qi |
| TWS headphones (reception) | 5 watts | Any 10 watts+ | Low current. |
| Other Android (distribution) | 10W | Not required | Reversing regime |
It’s worth noting that when using powerful third-party bases (like 30W), the phone will still take as much as its controller allows, but maximum 20W efficiency is achieved only when paired with the original 27W Xiaomi charger.
Indication and sound accompaniment
One of the handy features of the MIUI shell is the ability to fine-tune the phone's response to energy-related events. Sound signals help navigate the status of the device without looking at the screen. For example, a double beep usually means a successful start to the process, and an intermittent squeak can indicate a device's displacement or the presence of foreign objects.
In the wireless charging settings menu, you can find the option "Sound at Full Charge." If this feature is activated, the smartphone will play a tune when the battery level reaches 100%. This is especially useful if you use the phone as an alarm clock or if the base is in another room. However, at night this feature can be annoying, so it is better to turn it off.
There's also an important safety indication, which is that if the system detects critical overheating, the phone will force the current to stop and make a warning sound, at which point a notification may appear on the screen. Don't ignore these signals, let the device cool down by removing the case and removing it from the charging pad.
⚠️ Warning: If the phone is constantly beeping to interrupt charging, check the case. Some materials with added graphite or metal can shield the signal, making the controller think that the phone is constantly being removed and put back.
For users who value silence, there is a Do Not Disturb mode during charging, activating it, you turn off the light indication (if it is controlled programmatically) and sound effects, leaving only a visual display of percentages on the locked screen.
Charging problems and methods of their solution
Despite the reliability of the technology, users sometimes face situations where the Xiaomi Mi 9 refuses to charge without a wire. The most common reason lies in the wrong positioning. As mentioned earlier, the induction coil in this model is shifted upwards. If you put the phone geometric center on the center of the base, charging can go slowly or interrupt.
Another common problem is software failures of the power controller: in rare cases, the system may freeze in a standby state and not respond to the base, in which case a simple reboot of the device helps. If the problem persists, try clearing the cache of the battery system application through the application settings menu, displaying system processes.
List of actions in the absence of charging:
- 📏 Move your phone up or down the base to find the contact point.
- 🧹 Wipe the back cover and base surface from dust and contamination.
- 🔄 Reboot your smartphone to reset controller errors.
- 🔌 Check the power adapter connected to the base (it should be powerful).
If neither method works, the problem may be the hardware, the impact or fall may have damaged the inner coil or the plume connecting it to the motherboard, which would require a diagnosis at the service center.
Why is it charging now and then?
The Effects of Temperature and Safety of Use
Wireless power transmission technology is less efficient than wired power, and some of the power is inevitably lost as heat.For the Xiaomi Mi 9, which has a glass back cover, this is especially true. Glass does not remove heat well, so during intensive charging, the case can heat up to 40-45 degrees Celsius.
The MIUI safety system monitors temperature levels closely, and when critical values are reached (usually above 45-50 degrees), the charging speed will be artificially slowed, until the process stops completely, a protective mechanism that prevents the degradation of the lithium polymer battery and the battery from bloating.
To minimize heat and extend battery life, it is recommended not to use the phone actively while wirelessly charging. Running heavy games or the navigator at the time of replenishment will create a double load: the processor warms from computing, and the battery from current. It is best to put the phone on base overnight or when it is not in use.
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The optimal temperature for fast wireless charging is 15 to 25 degrees. Avoid direct sunlight on your phone while charging, as this is guaranteed to slow down or stop the process.
And you also have to consider that cold can affect charging as much as heat, and if you bring your phone in from the cold, the system can block charging until the device is warm to room temperature, which is the standard protection of battery chemistry against damage by lithium crystals.