How to enable fast charging on Xiaomi Mi 9: deal with Quick Charge 4+ and MI Turbo Charge

Why is the Mi 9 not charging fast?

Did you buy the Xiaomi Mi 9 with Quick Charge 4+ support, but the smartphone is charging hard for 2-3 hours instead of the promised 60-70 minutes? The problem is familiar to many owners of the 2019 flagship.It's not always a fault - often the fault is the wrong settings, unoriginal accessories or software limitations of MIUI.

In this article, we will discuss all the ways to activate fast charging on the Mi 9 (codename cepheus), including hardware verification, hidden MIUI settings and solving typical errors. Particular attention will be paid to the differences between Quick Charge 4+ (Qualcomm standard) and proprietary MI Turbo Charge technology, which works only with original Xiaomi charges.

Before you start, make sure your smartphone doesn't overheat while charging. If the case heats up above 40°C, the system automatically reduces the current to 5V/1A for safety. This is normal behavior, not breakdown!

1. Verification of equipment compatibility

Fast charging on the Xiaomi Mi 9 only works if three conditions are met:

• 🔌 The charger must support Quick Charge. 4+ (18V/2.5A) or MI Turbo Charge (27V/1.2Original adapter from the kit — MDY-11-ED (27V).
• 🔋 Cable only. USB Type-C with support for high currents (preferably the original Xiaomi or certified) USB-IF). Cheap cables often limit current to 10W.
• 📱 The charging port of the smartphone should be clean and intact. Contact oxidation or pollution reduces efficiency.

How do you check the charger? Put your smartphone in the socket and look at the lock screen. If it shows "Fast charging," the equipment is compatible. If it's not, use a different RAM.

⚠️ Note: Using uncertified chargers above 18V can damage the smartphone's power controller. Xiaomi officially recommends using only original accessories for the device. MI Turbo Charge.

2. Activation of fast charging in MIUI settings

By default, the Mi 9 can limit charging to 10W to save battery life.

1. Open Settings → Battery and Performance.
2. Select Battery Settings → Charging Mode.
3. Activate the "Enable fast charging" switch.
4. Reboot your smartphone – it’s a must for changes!

If Charging Mode is not on the menu, your MIUI version hides these settings, in which case unlocking hidden options through the engineering menu will help:

Check the MIUI version (must be at least 10.3)

Connect the original charger

Charge the battery to at least 30%

Turn off battery optimization for system applications-->

##4636## → “Battery Information” → Check the status “Fast Charging: Supported”

If the status is "not maintained", the problem is in the equipment (cable, charging or port). If "supported but not active" - reset the battery settings (more on this below).

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On some firmware, fast charging turns off when Charge Savings is activated (Settings → Battery → Charge Savings). Check this point if the smartphone suddenly starts charging slowly.

3. Resetting the power controller settings

If the smartphone was previously used with unoriginal charges, the power controller could "remember" the limited mode to reset it:

1. Connect the Mi 9 to the original charger.
2. Wait for the charging icon to appear on the lock screen.
3. Hold the power button + increase the volume for 10 seconds (until vibration).
4. After restarting, check the charging speed through the Ampere app (should show ≥1,500mA).

An alternative method is to reset through the engineering menu:

Dial ##284## → “ProjectMenu” → “Battery” → “Reset Battery Stats”

⚠️ Warning: Resetting battery statistics can temporarily increase charge consumption in the first few years 2-3 It's normal, the system recalibrates the battery capacity.

4. Checking the actual charging speed

To find out exactly if fast charging is working, use the Ampere app (free on Google Play).

• 📊 The charging current should be ≥1500 mA (for the QC 4+) or ≥2000 mA (for) MI Turbo Charge).
• 🔋 Tension — 9V/12For QC or 11V/27For MI Turbo.
• ⚡ The battery temperature should not exceed 40°C (or else speed will decrease).

Critical information: If the Ampere shows current ≤500mA when the charger is connected, this means that the smartphone has gone into slow charging mode due to overheating, damaged cable or a faulty power controller.

5. Solving typical problems

If the fast charging never worked, check out these points:

• 🔄 Smartphone charges fast to 80% – normal behavior MIUI After 80 percent, the current automatically decreases.
• 🌡️ Charging stops when heated – turn off the smartphone for 10 minutes, let it cool, then plug the charging again.
• ⚡ The Fast Charging icon flashes and disappears – reset your battery settings (see Section 3) or swipe your smartphone through the Mi Flash Tool.

⚠️ Note: If after the update MIUI If you have fast charging, you'll have to try to roll back to the previous firmware version, MIUI 12.5.3 for Mi 9) were charger recognition bugs.

6. Alternative methods of accelerating charging

If the standard methods did not help, try these techniques:

• ❄️ Cool your smartphone: Put it on a metal surface or use a cooling stand. 30°C charging current increases by 10-15%.
• 🛠️ Background Disconnect: Close all applications through Settings → Annexes → Background processes can limit current.
• 🔧 Aircraft mode: activate it while charging - this reduces the load on the processor and reduces heating.

For power users: If you are confident in your actions, you can turn off the charging restriction via ADB:

adb shell dumpsys battery set ac 1


adb shell dumpsys battery reset

This command resets the power controller’s limitations, but use it at your own risk – the wrong settings can damage the battery!

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Fast charging on the Xiaomi Mi 9 only works if three conditions are met: a compatible charger (27V or QC 4+), the original Type-C cable and a clean port. If any of the conditions are not met, the smartphone automatically goes into slow charging (5V/1A).

FAQ: Frequent questions about fast charging Mi 9