How to turn off fast charging on Xiaomi Mi 9 Pro: 3 proven ways

Xiaomi Mi 9 Pro

Quick Charge 4+

30W wireless charging

battery overheating

Many Mi 9 Pro users face a dilemma: on the one hand, the ease of charging in 40-50 minutes, on the other hand, the risk of reducing the life of the lithium polymer battery by 20-30% after a year of active use. In this article, we will analyze all the available ways to turn off fast charging, from standard settings to hidden features of the engineering menu, and find out whether it really helps to extend the battery life and in which cases it is better to leave the function on.

It’s important to understand that Xiaomi doesn’t provide a direct option to deactivate fast charging in the basic settings, and this is due to the brand’s marketing strategy, which positions fast charging as a key advantage of the model, but workarounds exist — and we’ve tested them in practice.

Why you should turn off fast charging on Xiaomi Mi 9 Pro

Lithium-ion and lithium-polymer batteries degrade over time, but intense high-current charging speeds up this process. Research from Battery University suggests that the constant use of fast charging can reduce battery life. 15-25% afterward 300-500 For the Mi cycles. 9 Pro with capacity 4000 mAh this means a noticeable reduction in the battery life through 1,5-2 year-end.

The main risks of fast charging:

• 🔥 Battery overheating - when charging with current >2A battery temperature may exceed 40°C, which is critical for its chemical composition.
• ⚡ Accelerated degradation of the anode - high voltage (>5V) provokes the formation of dendrites that reduce capacity.
• 📉 Unstable operation at low temperatures – after a year of intense charging, the smartphone may shut down in the cold due to increased internal battery resistance.
• 💥 Risk of battery bloating – in rare cases, uncontrolled heating leads to physical damage to cells.

On the other hand, fast charging is indispensable when traveling or when you need to urgently restore 50% of the charge in 20 minutes, the optimal trade-off is to use it situationally, and in everyday use switch to standard mode, which will extend the life of the battery without significant loss in convenience.

⚠️ Note: If you notice that the Mi 9 Pro is heating above 45°C during charging (can be checked in the engineering menu or app) AIDA64), Turn off fast charging immediately. Prolonged use at these temperatures causes permanent battery damage.

Method 1: Disconnecting through hidden MIUI settings

In the MIUI 11 and MIUI 12 firmware for the Xiaomi Mi 9 Pro, there is a hidden option to limit the charging current. It does not turn off the Quick Charge completely, but reduces the power to the standard charging level (~5W).

1. Open the Settings app.
2. Go to the About Phone section.
3. Tap 5-7 times on the MIUI version until you become a developer!
4. Go back to the main settings menu and open a new section for developers.
5. Find the Charging Limit (or Safe Charging option in some firmware versions).
6. Activate the switch and select 5W or 10W.

After the changes are applied, the smartphone will charge more slowly, but the battery temperature will not exceed 35 ° C even with a long connection to the network. This method does not require root rights and works on all versions of MIUI for the Mi 9 Pro.

Activate the Developer Mode

Check out the current version of MIUI

Connect the original charging unit

Close all background applications

Make a backup copy of settings (optional)-->

⚠️ Note: Some custom firmware (e.g. LineageOS or Pixel Experience) may not have Charging Limitation. In this case, use Method 3 with an engineering menu.

Method 2: Using third-party applications (without root)

If hidden MIUI settings are not available, you can use apps from Google Play that limit the charging current programmatically.The best options for Xiaomi Mi 9 Pro:

• 📱 AccuBattery – analyzes the battery status and allows you to set a charging limit of up to 80% (recommended for extending the service life.
• ⚡ Battery Charge Limit – blocks charging after a predetermined percentage is reached (for example, 70-80%), reduces the load on the battery.
• 🔧 3C Toolbox – Extended power management tool, supports charging current restriction (requires) ADB-access).

Example of settings in AccuBattery:

1. Install the application and provide all the permissions requested.
2. Go to the Charging section → Charging limit.
3. Set a maximum level, for example, 80%.
4. Activate the option to limit charging.

These apps don't turn off Quick Charge completely, but they reduce the charging intensity by simulating the standard mode. 1-3% day-to-day).

Method 3: Engineering menu (for power users)

The most reliable, but also the most risky method is the use of the #4636## engineering menu, which allows you to manually limit the charging current, but requires caution: incorrect settings can lead to unstable operation or even damage to the battery.

Instructions:

1. Open the Phone app and enter the combination: ##4636##.
2. In the menu that appears, select Battery Information.
3. Find the AC charge limit (or USB charge limit for wireless charging).
4. Set the value of 500 or 1000 (in mA).
5. Save the changes and restart the smartphone.

The advantage of this method is that it has complete control over the charging current, but there are also disadvantages:

• ❌ After updating MIUI settings may reset.
• ❌ Some firmware versions block access to the engineering menu.
• ❌ Risk of accidentally changing other critical parameters (e.g., Voltage limit).

💡

Before you change the settings in the engineering menu, take a picture of the current values, which will help you to return the settings to the original one if something goes wrong.

What to do if fast charging does not turn off

Sometimes, even after applying all the methods, the Xiaomi Mi 9 Pro continues to charge at high speed.

• 🔌 Non-original cable/power supply – some third-party accessories force Quick Charge activation. Use only the original kit or certified counterparts (e.g., from Anker or Baseus).
• 🔄 Resetting settings - after updating MIUI Charging parameters may reset. Reset the setting via an engineering menu or app.
• 🤖 Manufacturer restrictions – on some firmware versions (e.g, MIUI Global Stable 12.5) is locked to the option of disabling fast charging, in which case only unlocking the bootloader and installing custom firmware will help.
• 🔋 Damaged battery – if the battery is swollen or its capacity has fallen below 70%, the charging controller can ignore the restrictions.

If none of these methods worked, the radical option is to turn off fast charging at the hardware level.

1. Disassemble the smartphone and solder the resistor on the charge controller board (requires soldering skills).
2. Use a modified charger with reduced power (e.g. from an old 5W smartphone).

⚠️ Note: On models Xiaomi Mi 9 Pro with firmware MIUI 13+ Disabling fast charging via the engineering menu can cause a "No Charging Supported" error when connected to some wireless chargers. In this case, return the settings to factory or use only wired charging.

How to check if fast charging is actually off

To make sure that the restriction works, follow the following steps:

1. Connect the Mi 9 Pro to the charger.
2. Open the AIDA64 or AccuBattery app.
3. Go to the Battery or Charging section.
4. Check the current charging current: ✅ 300-1500 M.A. - Standard mode. ❌ 2000 MA and higher – fast charging is still active.

32-35°C

You can use it additionally. USB-tester (e.g. tester, VC820 or UM25C), It's a real-time, accurate voltage and current, and for standard charging, you have to be within the range of the parameters:

• Voltage: 4.8-5.2V
• Current: 0.5-1.5A
• Power: 2.5-7.5W

💡

If your smartphone starts charging too slowly (current < 300 mA) after you turn off fast charging, check the cable and power supply. They may be damaged or incompatible with the new settings.

Myths and Truths About Fast Charging on Xiaomi

There's a lot of rumors about fast charging, and we're going to look at the most common ones.

Myth 1: “Switching off fast charging completely stops battery degradation.”

Truth: Lithium polymer batteries degrade anyway, but slow charging reduces the speed of this process by 30-40%.

Myth 2: “Charging up to 100% kills the battery faster than fast charging.”

Truth: Both factors are harmful, but full charge (100%) It's more damaging than high recovery speed. It's optimal to keep the charge level in range. 20-80%.

Myth 3: “Xiaomi specifically blocks fast charging shutdowns to sell new smartphones.”

Truth: The manufacturer doesn't really advertise this feature, not because of malice, but because Quick Charge is part of the brand image, and most users prefer speed of durability.

Myth 4: “Wireless charging is safer for the battery than wired charging.”

Truth: On the contrary, wireless charging heats the battery up more because of the energy loss per induction, and if you have a choice, you'd better use a quality wired 5-10W charger.

FAQ: Frequent questions about turning off fast charging