With the latest update to MIUI, smartphone owners often experience unexpected behavior, and the Redmi Note 8 Pro is no exception, and many users have noticed that the usual zipper icon changes color or disappears altogether, and battery capacity dialing time increases significantly, which may be due to software resetting of power saving settings or changing the algorithms of the power controller.
Restoring the full functionality of Quick Charge 4.0 requires a comprehensive approach that includes checking both software parameters and the physical condition of accessories. The charge speed of 27 W on the Redmi Note 8 Pro is activated only if the QC4.0 technology is supported simultaneously by the power supply and the cable used. If you lose this option after the system update, do not panic - most often the problem is solved by correct reconfiguration or replacement of components.
In this article, we will take a closer look at all the possible reasons why your smartphone stopped charging fast, and provide step-by-step troubleshooting instructions, learn how to properly diagnose the problem using hidden engineering menus and system logs, and learn which cables are guaranteed to work with your device.
Diagnostics of the problem: why fast charging disappeared
The first step is to pinpoint the source of the malfunction, and after the firmware update, the system could reset the battery optimization settings or, conversely, activate an aggressive current-limiting protection mode, and the possibility of physical damage to the Type-C port or degradation of the battery itself cannot be ruled out.
Consider that modern versions of MIUI have complex protection algorithms that can block fast charging when the device overheats or uses non-original accessories. The system analyzes the resistance of the cable and the voltage at the input, and if the parameters go beyond the permissible limits, the charging speed is forcibly reduced to the standard 5 or 10 watts.
⚠️ Warning: If the phone gets too hot during charging, disconnect it immediately from the mains.Attempting to force a fast charge on an overheated device can cause the battery to bloat or the power controller to fail.
For initial diagnosis, look at the indicator in the status bar. Standard charging is displayed with one lightning, fast charging with two, and turbo charging (relevant to newer models, but sometimes found in logs) with special icons. If the icon does not change, the problem lies in the hake protocol between the hands charger and the smartphone.
Checking the compatibility of the charger and cable
The most common reason for the lack of fast charging is the discrepancy of the characteristics of the adapter used to the requirements of Xiaomi Redmi Note 8 Pro. Your smartphone supports Quick Charge 4.0+ technology, which means the need to use a power supply with appropriate marking and support for PD (Power Delivery) protocols.
The cable is just as important as the power supply itself. Cheap wires often can't withstand the current of 3 Amps or higher, which is necessary to realize the power of 27 watts. When you upgrade the system, the power controller can become more sensitive to the resistance of the cable, which causes the previously working bunch to stop activating the fast mode.
Visual inspection of the cable plug and the phone connector is recommended. Oxides, dust, or mechanical damage to the contacts can disrupt data transmission over the CC lines, which are responsible for coordinating the fast charging protocol. Use a soft brush and isopropyl alcohol to clean the port accurately.
System settings and battery optimization in MIUI
The newer versions of the MIUI have advanced power management features that can conflict with fast charging, and once updated, it’s worth manually checking if Super Energy Saving mode or other restrictions that the system could have enabled automatically to extend battery life are activated.
Go to Settings → Battery → Top Right gear → Functions. Here, make sure that the options for Accelerated Charging (if available in your firmware version) or Charging Optimization are set correctly. Sometimes it helps to disable and re-enable these functions to reset the state.
☑️ Checklist settings MIUI
Also worth paying attention to is the Security app, which has built-in antivirus and optimizer that can block the background processes that monitor charging, try doing a deep cleaning through this app, and then reconnect the charger.
Hidden Engineering Menus and Testing
For a deeper diagnosis, you can use the Xiaomi engineering menu, which provides access to technical tests of equipment, which will allow you to check the real state of the battery and the operation of the charge controller without installing third-party software.
To enter the test menu, open the Phone app and dial the combination ##6484##. From the menu that opens, select Battery info or Charging test. Here you will see the current voltage, current strength and battery temperature in real time.
| Parameter | Normal value. | Critical significance |
|---|---|---|
| Voltage (Voltage) | 3.8V - 4.4V | < 3.5V or > 4.5V |
| Charge current (Current) | 2000mA - 3000mA (at QC) | < 1000mA |
| Temperature. | 25°C - 35°C | > 45°C |
| Status (status) | Charging | Not Charging / Unknown |
If the engineering menu displays a current of less than 1 Amp when a powerful power supply is connected, this indicates a software lock or port malfunction, in which case it may be necessary to reset the settings to the factory or flash the device.
Resetting and calibration of the battery
If the software settings are lost after the upgrade, a full battery calibration can be an effective method, which helps the system re-determine the actual battery capacity and correctly display percentages, which sometimes affects the charging algorithms.
The calibration procedure is as follows: completely discharge the phone before turning it off, then charge it when it is off to 100%. After reaching full charge, leave the device for another 1-2 hours, then turn it on. If the charge level is less than 100%, put it on charge again.
Do I need to do a full reset?
As a last resort, if nothing works, you can try resetting everything to factory settings. Before you do, make sure you have a backup. After you reset, don't restore all applications from the backup at once - check the charging on a clean system.
Hardware malfunctions and repairs
Remember that the software update may have just coincided with the failure of hardware components. On the Redmi Note 8 Pro (a common problem) is loosening the bottom plume or oxidation of the board after moisture.
If you notice that charging only starts at a certain position of the cable or the plug is hanging in the socket, you probably need to replace the charging connector (sub-board), which is an inexpensive procedure that can be performed in a service center.
⚠️ Warning: Self-disassembly of the smartphone can lead to loss of warranty and damage to the plumes.If you are not confident in their abilities, better contact the professionals.
It is also worth checking the status of the battery itself if it is already more than that. 2-3 In the years since, its internal resistance may have increased, and the controller simply does not allow high current to be supplied to avoid overheating and bloating, in which case only a replacement battery will help.
💡
If no software method has worked, the 90% probability problem is the cable, charger, or physical wear of the Type-C connector.