Modern smartphones like the Xiaomi Redmi Note 9 Pro feature technologies that dramatically speed up battery energy recharge. Quick Charge or proprietary MIUI Turbo Charge can restore battery capacity to 50% in just 30 minutes. However, constant operation at maximum currents can lead to heating of the device and accelerated wear of the chemical structure of the battery.
Many users prefer to charge the gadget slowly, for example, at night, to reduce the heat load. This is especially true for owners of the Redmi Note 9 Pro model, whose Snapdragon 720G processor already emits significant heat. In the standard Android settings menu, the option of completely turning off this feature is often hidden or absent, which requires additional methods.
In this article, we’ll look at all the ways you can limit your charging speed, including using an engineering menu, hidden codes, and third-party apps, and learn how to control your device’s power consumption to extend battery life.
Why turn off fast charging on the Redmi Note 9 Pro
The main reason for the failure of high-speed protocols is heat generation. When charged with high-power current (for example, 27 watts for this model), the chemical reactions inside the lithium-polymer cell proceed more intensely, which inevitably leads to an increase in temperature. Constant heating destroys the electrolyte and reduces the overall capacity of the battery over time.
In addition, the Redmi Note 9 Pro has a glass back panel that does not remove heat well. If you charge your phone under a pillow or in a case, the risk of overheating increases many times.
⚠️ Warning: Turning off fast charging doesn't mean the phone will stop charging; it will just consume standard current (usually up to the current level). 10 W) which will increase the full charge time in 2-3 once.
There is also a belief that slow charging contributes to better calibration of the power controller. 10-15%, Change the charger's mode of operation, which can help the system better determine the residual capacity.
Checking current charging parameters
Before you make changes to the system, you need to make sure that your smartphone really uses the accelerated protocol. Xiaomi Redmi Note 9 Pro supports the Quick Charge 4.0+ standard. When you connect the original cable and power supply, special animations appear on the lock screen.
Usually it's a "Mi Turbo Charge" or a "Quick Charge" with the current wattage, and if you see just a lightning icon without any additional labels, it means that fast charging is no longer active, and this may be due to poor-quality cable or the use of a third-party power supply.
For more detailed diagnostics, you can use engineering codes or monitor applications to show you the exact voltage and current strength in real time, and that will help you understand how effective your next power-limiting action is.
- 🔌 Original charging gives up to 27 watts and displays the logo "Turbo Charge".
- 🔋 Standard charging (USB 2.0) quiver 10 Watt (5V/2A) without special logos.
- ⚡ Slow charging (through a USB-PC port) does not provide more 2.5-5 Watt.
- 📱 On-screen animation is the fastest way to visually check mode.
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Use cables labeled 3A or 5A to support fast charging. Thin cables from older devices won't physically let high current through, automatically putting the phone back to normal mode.
Use of the MIUI Hidden Engineering Menu
In the MIUI shell, which is the basis of the Android system in Xiaomi phones, there is a hidden section for engineers to manage certain hardware parameters, including battery testing. However, a direct switch to turn off fast charging is rare here, but you can check the status of the battery.
To enter the menu, you need to enter a special code in the Phone app. Dial the combination ##6484##. The CIT menu will open. Here we are interested in the Battery section. Some firmware versions have a calibration reset option, which indirectly affects the charging logic.
Be careful when changing the settings in the engineering menu. Incorrect actions can lead to incorrect display of the percentage of charge. If you are not sure of your actions, it is better to limit yourself to just looking at the information.
##6484##Alternative code to log into the extended menu is ##4636##. Go to Battery Information. This shows the current settings: voltage, temperature and charging status. Although there is no switch here, monitoring these values will help you understand if the phone is warming.
⚠️ Attention: The engineering menu is for professionals, don't change meanings you don't understand, especially in the Radio and Network sections.
Speed Limitation through Developer Settings
One of the software ways to affect charging speed is to activate the developer menu, and although there's no direct current limit button, you can turn off some optimization features that can indirectly affect how the system behaves when it connects to the network.
To open the menu, go to Settings. → Find the line "Version." MIUI" And press it fast. 7-10 A notification will appear, "You've become a developer." Then a new option will appear in the main settings menu "Additional" or "Extended settings", where there will be a section "Developers".
Inside this section, look for energy-saving options, such as "Don't turn off the screen when charging" -- this feature doesn't affect current, but changes the behavior of the system -- and a more useful one might be to reset Bluetooth and Wi-Fi settings, which sometimes cause background discharge masquerading as charging problems.
☑️ Checking the developer's settings
It is worth noting that in the latest versions of Android 10/11 based on MIUI 12/13, direct charging current restriction through this menu was removed by developers for security reasons.
Physical methods of reducing the charging speed
The safest and most reliable way to turn off fast charging on the Redmi Note 9 Pro is to use a physical constraint. Fast charging protocols work on the principle of matching: the phone "requests" the power supply a certain voltage and current. If the power supply is weak or the cable does not meet standards, the phone automatically goes to safe mode.
You can use the power supply from an old smartphone with a power of 5 W (5V/1A) or 10 W (5V/2A).In this case, the Redmi Note 9 Pro will not be able to activate the Quick Charge protocol and will charge at standard speed.
You can also use it. USB-port of a computer or laptop. Standard port USB 2.0 gives only 0.5 Ampere, and USB 3.0 is about 0.9 Amps. It's very slow, but perfect for overnight charging if you have nowhere to rush.
| Type of source | Power (example) | Charging time Redmi Note 9 Pro | Heating the hull |
|---|---|---|---|
| Original 27W charging | 27 watts (Turbo Charge) | ~65 minutes | High-pitched |
| Power supply 10W (5B/2A) | 10 Watts. | ~2.5 hours | Low. |
| Power supply 5W (5B/1A) | 5 watts | ~4-5 hours | Minimum |
| USB port of the computer | 2.5 - 4.5 W | ~6-8 hours | Absent. |
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Using a weak power supply (5-10 W) is the only guaranteed way to turn off fast charging without root rights and complex software.
Third-party applications for charge control
For users who don't want to change chargers, there are software solutions, applications like AccuBattery or Battery Charge Limit that allow you to monitor battery status and, in some cases, limit the charge, but root rights are often required to fully control current at the system level.
Without super-user rights, these apps can only notify you of reaching a certain percentage (e.g. 80%) with an audible signal, recommending that you turn off the cable. This helps avoid overcharging, but does not reduce the rate of energy in the first minutes.
Some advanced utilities can emulate the power out of charge programmatically, but on modern versions of Android, it works unstable. Security can block such interventions. However, monitoring temperature through such applications is useful: if you see degrees rising, just remove the case or remove the phone from the sun.
- 📊 AccuBattery is the best application for analyzing battery health and wear rate.
- 🛑 Battery Charge Limit – requires root, but can stop charging at a given level.
- 🌡️ CPU-Z — Shows the actual temperature of the battery in real time.
- ⚙️ Ampere – displays the current of charge and discharge, helping to identify background processes.
⚠️ Note: Apps that promise to “speed up” or “slow down” charging without root rights are often fakes, and they only show banner ads without affecting the actual physics of the process.
Why are root rights dangerous?
The effect of temperature on speed
It is important to understand that the Xiaomi Redmi Note 9 Pro is equipped with a system of protection against overheating. If the battery temperature exceeds a certain threshold (usually 40-45 ° C), the power controller automatically reduces the current, even if you have a powerful charge.
Sometimes users want to artificially create conditions to slow down charging, but doing so is dangerous. Heating the phone in the sun or near the battery can cause the battery to bloat. It is better to ensure good cooling: remove the dense case, put the phone on a cool surface (pot, metal).
If you notice that the phone is charging slowly without your intervention, check the charging port. Dust or pile that gets there can disrupt contact between contacts responsible for the fast charging protocol.