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

Xiaomi Redmi 9 is equipped with a battery capacity of 5020 mAh, but not all users know that the device supports fast charging technology with a power of up to 18 watts. By default, the function can be turned off or not work at full power due to system settings, incompatible charger or damaged cable. In this article, we will discuss how to properly activate fast charging, which adapters are suitable for Redmi 9, and why sometimes the smartphone charges slowly even when connected to a “native” RAM.

It’s important to understand: Xiaomi Redmi 9 (model M2004J19C) officially supports Quick Charge 3.0 protocol, but it requires not only a compatible power supply, but also the correct settings in MIUI. If you connect the original charger, but the charging indicator shows “Normal Charging”, the problem lies in software limitations or hardware malfunctions. Next are step-by-step instructions for all scenarios.

1. Checking the compatibility of the charger

Before you change your smartphone settings, make sure your power adapter supports fast charging. Xiaomi Redmi 9 requires a power supply with output options:

• 🔌 Power: minimum 18 Watt (9V/2A or 12V/1.5A).
• 🔋 Protocol: Quick Charge 3.0 or USB Power Delivery (PD).
• ⚡ Cable: USB Type-C with support for high currents (better original from Xiaomi).

The original Redmi 9 charger has 10 watts (5V/2A) and doesn’t support fast charging. This is Xiaomi’s marketing ploy: the smartphone is technically capable of charging faster, but you need to buy an adapter separately.

How to check the current charging power? Connect your smartphone to your adapter and open the Safety → Battery app. The consumption schedule will show the words “Fast Charging” (if everything works) or “Normal Charging” (if the adapter is incompatible).

2. Enabling fast charging in MIUI settings

Even with a compatible adapter, the Redmi 9 can charge slowly due to software constraints. MIUI has hidden settings that affect charging speed.

1. Open the settings → Battery and performance.
2. Slip on the battery settings → Charging mode.
3. Select the option “Fast Charging” (if available).
4. Activate the option to Enable Fast Charging (could be called Accelerated Charging).

If the Quick Charge option is not on the menu, your adapter doesn't support Quick Charge, or your smartphone doesn't recognize it because of a damaged cable.

Try another cable (preferably the original Type-C)

Connect the RAM to another device (check if the fast charging is running on it)

Clean the dust charging port with a toothpick (carefully!)

Reboot your smartphone and reconnect.-->

A critical feature of Redmi 9: the smartphone automatically turns off fast charging at a battery temperature above 40 ° C or below 10 ° C. If you charge the device in the heat or in the cold, the system will switch to normal mode. Check the temperature in Settings → Battery → Battery status.

3. Reset charging settings (if the function is not activated)

Sometimes MIUI settings are lost after updating the firmware, and the smartphone “forgets” the Quick Charge protocol.

1. Go to Settings → Applications → Application Management.
2. Find the Security (or Security) app.
3. Slip the vault. → Clear the data.
4. Reboot your smartphone and connect the charger again.

If this doesn’t help, try resetting the battery settings via the engineering menu:

##4636## → Tap “Battery Information” → “Battery Statistics Reset”

Attention! Don't confuse this reset with hard reset - it doesn't delete your data, it only resets charging statistics, which sometimes helps restore Quick Charge to work.

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If the fast charge started after the reset, but disappeared again after a while, check if its application turns off to save battery (for example, Greenify or AccuBattery).

4.Cable and charging port problems

A common cause of slow charging is a damaged cable or a contaminated Type-C port. Redmi 9 is particularly sensitive to connection quality: if the contacts are oxidized or bent, the smartphone automatically reduces the charging current.

How to check the cable:

• 🔍 Check the connector for cuts, melts or bare wires.
• 📱 Connect the cable to another device (like the Redmi Note 10) and check if fast charging is working.
• ⚡ Use a labeled cable 5A (usually indicated on the shell near the connector).

How to Clean Type-C Port:

1. Turn off your smartphone.
2. Light the port with a flashlight and remove the dust with a plastic toothpick (not metal!).
3. Wipe the contacts with an alcohol napkin (without excess liquid!).
4. Allow the port to dry for 10-15 minutes before connecting.

⚠️ Warning: Never use needles, pins or other metal objects to clean the Redmi 9 port - this can close contacts and disable the charging controller.

5. Software limitations: why MIUI blocks fast charging

Xiaomi introduces software limitations on charging in some scenarios:

• 🔋 Battery wear and tear > 80%: If the battery capacity falls below the threshold, the system disables Quick Charge for safety.
• 📉 Power saving mode: when activated, ultra-economic mode, fast charging is automatically deactivated.
• 🔄 Unoriginal firmware: custom ROM (LineageOS may not support Quick Charge 3.0.

To check the wear of the battery:

1. Install the AccuBattery app from Google Play.
2. Charge your smartphone to 100% and wait for calibration (1-2 cycles).
3. See the Health value in the Battery Health section.

If the wear exceeds 30%, it is recommended to replace the battery - this will not only return fast charging, but also increase battery life. The original battery for the Redmi 9 has an article MB127.

6. Alternative methods of accelerating charging

If fast charging never worked, you can optimize the process by other methods:

• ❄️ Smartphone cooling: Put Redmi 9 on a metal surface or use a cooling stand. at temperatures below 30°C charging goes 10-15% faster.
• 🛑 Background Disconnection: Close all applications and activate Flight Mode – this will reduce the load on the processor.
• 🔄 Battery calibration: discharge the smartphone to 0%, then charge to 100% without interruptions (repeat 2-3 times).

Extreme method (power users only): If you are confident in the quality of your RAM, you can force fast charging via ADB:

adb shell settings put global fast_charge_forced 1

This command forces the smartphone to ignore the compatibility check adapter, but use it at your own risk - incompatible power supplies can damage the charging controller.

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Fast charging on Redmi 9 works only under three conditions: compatible adapter (18W+), original Type-C cable and battery temperature in the range of 10–40°C. If at least one of them is not met, the smartphone will switch to normal mode.

FAQ: Frequent questions about Redmi fast charging 9