How to turn off fast charging on Xiaomi Redmi Note 9: safe and without risk

Xiaomi Redmi Note 9 is a popular smartphone with fast charging technology that allows you to restore battery power in minutes. However, this advantage has a downside: accelerated charging can overheat the battery, reducing its life by 15-20% in 1-2 years of intensive use. If you notice that the phone heats up during charging or the battery began to sit down faster, disabling the Fast Charge function can be a solution.

In this article, you will find 3 proven ways to disable fast charging on the Redmi Note 9 (including the Note 9 Pro and Note 9S models), and also understand when it is really necessary. We will not use universal tips - only specific instructions, taking into account the features of the MIUI firmware and the Qualcomm Snapdragon hardware platform.

Why you should turn off fast charging on the Redmi Note 9

Quick Charge 3.0 (or Fast Charge in Xiaomi terminology) increases the charging current to 3A and voltage to 9-12V, allowing you to charge the battery by 50% in 30 minutes.

🔥 Overheating of the battery - the temperature can rise to 45-50°C, which accelerates the degradation of lithium-ion elements.
⚡ Reduced charging cycles – with constant use of fast charging, the battery loses up to 30% of capacity in 500 cycles (versus 800-1000 in standard charging).
📉 Unstable operation – some users note occasional reboots when charging due to voltage surges.
🛠️ Wear of the connector USB-C — High current accelerates the oxidation of contacts, especially when using poor-quality cables.

Disabling fast charging is advisable in the following cases:

⚠️ Note: If you use the Redmi Note 9 in high temperatures (such as in a car in the summer), turning off the Fast Charge is a must – the combination of external heat and fast charging can cause the battery to bloat.

But there is a downside: without fast charging, battery recovery time will increase to 2.5-3 hours (versus 1.5 hours with Fast Charge), and the decision must be made consciously – we will explain below how to check the battery status before turning off the function.

📊 You turned off fast charging on your smartphone?

Yeah, to save the battery.

No, convenience is more important.

I tried it, but I went back to fast charging.

I don't know how to do that.

How to check the status of the battery before turning off fast charging

Before you turn off the Fast Charge, make sure the problem is really charging, not battery wear.

Go to Settings → Battery and Performance → Battery Status
Check the Battery Capacity option – if it is below 80%, the battery has already degraded, and turning off fast charging will give a minimal effect.
Pay attention to the temperature chart – if it exceeds 40°C during charging, it is a direct signal to action.

Parameter	Normal value.	Critical significance
Battery capacity	> 90%	< 80%
Temperature during charging	25–35°C	> 45°C
Full charge time.	1.5–2 hours (with Fast Charge)	> 3 hours (without Fast Charge)
Number of charging cycles	< 300	> 500

If the battery capacity is normal but the phone is warming, try the following first:

🔌 Use the original charger from Xiaomi (power) 18W or 33W Note 9 Pro).
📵 Charge your phone in airplane mode – this will reduce the load on the processor.
🌡️ Avoid charging at ambient temperatures above 30°C.

💡

If your phone is still warming after you turn off Fast Charge, check the background processes in the Settings menu → Apps → Running. Often, optimizers or games running in the background are causing overheating.

Method 1: Disable fast charging via hidden MIUI settings

The most reliable method is to use the MIUI engineering menu, which works on all firmware versions, including MIUI 12/13/14, but requires carefulness:

☑️ Preparing to turn off Fast Charge

Make a backup copy of the dataCharge your phone at least 50%Use the original cableDon't interrupt the setup process

Done: 0 / 4

Open the Phone app and type the combination: ##4636## This will open the Testing menu.
Select the Battery Information item.
Click on the three-point menu (in the upper right corner) and select Battery Settings.
Find the Fast Charge (or Quick Charge) option and uncheck the box.
Restart your phone to apply the changes.

If there is no Fast Charge, try an alternative path:

Go back to the main testing menu and select Hardware Testing.
Go to Battery. → Charging Control.
Turn off the Enable Fast Charging option.

⚠️ Note: On some versions MIUI (For example, the global 12.5.3) engineering menu may be blocked.In this case, use Method 2 or Method 3.

What to do if the engineering menu is not opened?

If the ##4636## combination doesn’t work, try entering it through the Calculator app (enter 4636=). On some firmware, Xiaomi blocks access to the engineering menu, in which case only flashing or using ADB (Method 3) will help.

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

If standard methods didn't work, you can use apps from Google Play that control charging options.The best options for the Redmi Note 9 are:

📱 AccuBattery – analyzes the battery status and allows you to limit the charging current to 1A (without root).
⚡ Battery Charge Limit – sets a charging limit (e.g. up to 80%) that extends battery life.
🔧 Quick Charge Disabler – a specialized application to disable Fast Charge (requires) ADB).

Instructions for AccuBattery:

Install the app from Google Play and provide all the necessary permissions.
Go to the Charging section → Current restriction.
Set a maximum current of 1000 mA (or 500 mA for gentle mode).
Activate the option to Enable the Limit.

Limitations of the method:

❌ Applications without root do not block Fast Charge completely, but only limit current.
❌ After restarting, the phone can return to standard settings.
❌ Some applications require ADB For work (instructions in Method 3).

💡

The app side is a temporary solution. To completely disable the Fast Charge on the Redmi Note 9, you will need either an engineering menu or ADB commands.

Method 3: Disable fast charging via ADB (for power users)

If previous methods fail, the system is disabled via ADB (Android Debug Bridge), which requires a computer but is guaranteed to work on all versions of MIUI.

What you need:

💻 A computer with installed Xiaomi drivers and ADB.
📱 Included debugging by USB phone-on.
🔌 The original cable. USB-C.

Step-by-step:

Activate Developer Mode: Go to Settings → About Phone. Click on MIUI 7 times until you become a developer!
Return to Settings → More → For Developers and Enable: Debugging over USB OEM Unlock (if any)
Connect the phone to your computer and confirm the debugging permission.
Open the Command Prompt (or Terminal) Mac/Linux) Enter: adb shell settings put global fast_charge 0
Reboot the phone.

To return fast charging, use the command:

adb shell settings put global fast_charge 1

⚠️ Attention: Misuse of the right ADB If you are not sure about your actions, refer to Method 1 or Method 2.

What to do if fast charging does not turn off

If none of the methods worked, the problem may lie in the following:

🔄 Firmware MIUI Blocks changes on some versions (e.g, MIUI 14 for global region) charging settings are limited.
🔧 The connector is damaged. USB-C — If contacts are oxidized, the phone can ignore commands.
📱 Hardware malfunction of the power controller - in this case only the service center will help.

Alternative solutions:

Use a charger with less power (e.g. 5W instead of 18W).
Charge the phone in the off state - this will reduce the load on the battery.
Update the firmware – newer versions of MIUI sometimes return access to hidden settings.

If the phone is still warm, check it for battery bloating:

Put the Redmi Note 9 on a flat surface and spin - if it swings, the battery is swollen.
Look at the screen: if it is “moving away” from the body, it is a sign of deformation.

💡

If the battery is swelling, stop using the phone immediately! the bloated battery may ignite. contact Xiaomi's service center for replacement.

How to return a quick charge if needed

If you have temporarily disabled Fast Charge but want to return it back, use one of the methods:

Method	Action.	Note
Engineering menu	Go back to #4636## and turn on Fast Charge.	It doesn't work on all firmware.
ADB	Adb shell settings put global settings fast_charge 1.	He needs a computer.
Resetting settings	Make a reset to factory settings (Settings → About phone → Reset).	Delete all data!
MIUI Update	Update the firmware through Settings → System Update.	Sometimes it returns standard settings.

If you have used third-party applications (such as AccuBattery), it is sufficient to:

Open the app.
Go to Charging section.
Turn off the current limit.

Frequent questions about fast charging on the Redmi Note 9

❓ Disabling Fast Charge will damage your phone?

No, turning off fast charging doesn't hurt the phone; on the contrary, it can extend battery life by 20 to 30 percent, the only downside is the increase in charging time.

❓ Can I turn off fast charging only at night?

Yes, AccuBattery, which has a time limit setting, can do that, and you can use smart timer outlets to interrupt charging after you reach 80%.

❓ Why is it that after turning off Fast Charge, the phone still warms up?

The reasons may be different: 🔌 Used poor-quality cable or power supply. 📱 Resource-intensive applications work in the background. 🔋 Battery worn out (capacity) < 80%) Check the temperature through Settings → Battery → Battery status.

❓ Will wireless charging work after Fast Charge is turned off?

Yes, disabling Fast Charge via cable doesn't affect wireless charging (if supported by your model), however wireless charging itself is less efficient and warms the phone more.

❓ How to check if fast charging is turned off?

There are two ways: Connect your phone to charge and look at the lock screen -- if the Fast Charge's reliability doesn't show up, the function is disabled. Use the Ampere app (from Google Play) to show the current charging current. >1500 CA, with standard — <1000 ma.