How to turn on fast charging on Xiaomi Redmi 9 Pro: all the ways and nuances

Why fast charging on the Redmi 9 Pro may not work out of the box

Xiaomi Redmi 9 Pro is equipped with support for fast charging technology (18W), But many users are faced with the fact that the smartphone charges slowly, even with the original charger, the reason is not the hardware limitations, but the software settings and the features of the firmware. MIUI.

The fact is that by default, the Redmi 9 Pro can limit charging power to extend battery life. In addition, not all cables and power adapters are capable of transmitting sufficient current. In this article, we will discuss all ways to activate fast charging, including hidden settings, checking equipment compatibility and solving typical problems.

1. Checking the compatibility of the charger and cable

Before you change your smartphone settings, make sure your charger and cable support fast charging.The Redmi 9 Pro requires a power adapter with a power output of at least 18W (5V/3A or 9V/2A) and a cable that supports USB Type-C 2.0 or higher.

Xiaomi’s original charger (MDY-11-ED) is fully compatible, but if you’re using third-party accessories, pay attention to the following options:

• ⚡ Adapter power: should be ≥18W (hulled).
• 🔌 Fast Charging Protocol: Quick Charge 3.0/4.0 or USB Power Delivery (PD).
• 📶 Cable: must support current ≥3A (is usually referred to as a "fast charge" or "3A" plug-in).

Importantly, cheap cables without certification can not only block fast charging, but also damage the smartphone's power controller. If you suspect that the problem is accessories, try charging the phone with the original kit.

2. Activate fast charging via MIUI settings

MIUI has hidden and explicit options that affect charging speed, starting with the basic settings:

1. Open Settings → Battery and Performance.
2. Select Charging.
3. Activate the Quick Charging switch (if available).

If you don't have an option, it means your MIUI version automatically adjusts the power, so go to the hidden settings:

Check out the MIUI version (Settings → About the phone)

Connect the original charger

Make sure the battery is less than 80% discharged.

Turn off battery optimization (Settings) → Battery → Battery mode → High productivity)-->

To access the extended parameters:

1. Enter the combination in the Phone app: ##4636##.
2. Go to the section Information about the battery.
3. Check the AC powered bar – if the USB value is not activated, then fast charging is not activated.

If after these actions the charging speed has not changed, proceed to the next section.

3. Disable battery optimization to accelerate charging

MIUI default includes features that extend battery life, but they can limit charging current to turn them off:

1. Go to Settings → Battery and Performance → Battery Mode.
2. Select High Performance mode (instead of Balanced or Energy Saving).
3. Return to the basic battery settings and turn off the charging optimization option (if it is active).

It is also recommended to turn off adaptive charging, which artificially slows down the process when it reaches 80%:

1. Go to Settings. → Battery → Settings (⚙️) → Adaptive charging.
2. Deactivate the function.

💡

If after switching off the optimization, the smartphone began to warm up while charging, use it without a case and avoid direct sunlight.

These changes can increase the charging speed by 20 to 30 percent, but keep an eye on the temperature of the device.

4. Checking the temperature and condition of the battery

Fast charging automatically turns off if the battery temperature exceeds 40°C or falls below 0°C. To check the current readings:

1. Install the AIDA64 or AccuBattery app from Google Play.
2. Open the Battery section and see the current temperature.
3. If the value is above 35°C, let the phone cool down before charging.

Also, pay attention to the state of the battery:

If the battery capacity has dropped below 80%, fast charging may not work smoothly, in which case consider replacing the battery.

5. Resetting charging settings and battery calibration

If previous methods didn’t help, try resetting your power-related settings:

1. Go to Settings → System → Resetting settings.
2. Select Reset Battery Settings (not to be confused with a full reset!).
3. Confirm the action and restart the phone.

After reset, calibrate the battery:

1. Reduce the phone to 0% (until it turns off).
2. Connect the original charger and charge up to 100% without interruptions.
3. Repeat the cycle 2-3 times.

This procedure helps the power controller to more accurately determine the actual charge level and optimize the charging process.

💡

Resetting the battery does not delete personal data, but returns all power settings to factory values. After the procedure, fast charging can work even with third-party adapters (assuming they are compatible).

6. Update of firmware and system core

In some versions of MIUI (especially older or customized ones), fast charging can be turned off at the core level.

1. Check the current firmware version: Settings → About Phone → MIUI version.
2. If the version is older than MIUI 12.5, update it via Settings → System Update.
3. After the update, reset the battery settings (see the previous section).

If the official updates don't work, you can try to flash your phone over Fastboot or Recovery, but it takes experience. It's not recommended to use informal firmware - they can disrupt the power controller.

7. Alternative methods of accelerating charging

If the standard methods didn’t work, try these additional techniques:

• 🔄 Restart Safe Mode: Sometimes background apps block fast charging. Press the power button, hold off Power Disconnect until the Safe Mode window appears.
• 📵 Network Disconnection: Turn off Wi-Fi, mobile data and Bluetooth while charging – this will reduce the load on the processor.
• ❄️ Phone cooling: use a cooling stand or point a fan at the body (but not ice air!).
• 🔌 Use of the port USB-C PC: Some laptops (such as MacBook Pro or Dell) XPS) support USB-C PD It can charge the Redmi 9 Pro faster than standard RAM.

You can also try to force activation of fast charging via ADB (power users only):

adb shell settings put global fast_charge_forced_enable 1

⚠️ Attention: Team ADB It can cause system instability if the firmware does not support forced activation. Use it only if you are sure of compatibility.

8. Diagnostics of malfunctions: when to contact the service

If none of the methods worked, the problem could be hardware.

• ⚡ Charging is only off - a malfunction of the power controller is possible.
• 🔥 The phone is very warm even without a load - damaged battery or motherboard.
• 🛑 ROM is not determined (no charging indication) - connector problem USB-C.
• 📉 Battery capacity drops 10-20% overnight – critical battery wear.

In these cases, self-repair is not recommended. Contact the authorized Xiaomi service center with a diagnostic card (it can be formed in the Mi Service application).

⚠️ Warning: If you have previously dropped your phone or exposed it to moisture, do not try to turn on fast charging - this can lead to a short circuit.

FAQ: Frequent questions about Redmi fast charging 9 Pro