Xiaomi smartphone owners often face a situation where the device begins to discharge faster, although the specifications of the battery should hold confident.The diagnostic issue is especially relevant for users who have purchased a used device or have been operating the gadget for more than two years. MIUI 12 offers several built-in tools for analysis, but they are not always obvious to the average user.
It is critical to understand that software diagnostics does not always show 100% truth about the chemical state of a battery, but the combination of system reports and hidden codes allows you to get the most accurate picture without opening the case. In this article, we will discuss all available methods, from simple notifications to deep analysis through the engineering menu.
Before you start complex manipulations, it is worth assessing the subjective sensations of the smartphone. If the device warms up in the idle or turns off at 15-20% charge, these are sure signs of degradation of the Li-Po battery. Software methods will only confirm your guesses with specific numbers.
Use of the built-in "Security" application
The most affordable method of initial diagnosis is the use of the regular application Safety, which is preinstalled on all Xiaomi smartphones with a MIUI shell. This tool does not show the exact percentage of wear (SOH), but is able to identify critical errors in the operation of the power system.
Launch the app and go to the diagnostics section, the system will automatically check all key nodes, including battery temperature and voltage, and if anomalies are found, you will receive a notification recommending you contact the service.
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If the Security app doesn’t find errors, but the phone shuts down in the cold, the problem may be in the power controller, not the battery itself.
To access more detailed data on energy consumption, go to the system settings, and here you will see the application discharge statistics, which will help identify the "parasitic" processes that land the battery faster than it physically wears out.
- 🔋 Open the Security app on the home screen.
- 🔋 Click on the Diagnostic button or lightning icon.
- 🔋 Wait for the inspection to be completed and examine the results.
- 🔋 Go to Settings. → Battery for consumption analysis.
It's worth noting that standard diagnostics often ignores a slight drop in capacity if it doesn't exceed safety thresholds, so relying on this method alone when buying a used device is not a good idea.
Hidden Codes and CIT Engineering Menu
The most accurate information about the state of the hardware can be obtained through the hidden engineering menu. CIT (Customer Interactive Test: This is a factory-based service interface that is hidden from the general public but accessible through dedicated testing. USSD-code.
To enter the menu, open the Phone app and type ##6485##. On screens with a MIUI 12 shell, this action should automatically open the window with technical information. If the code does not work, it is possible that your operator or firmware will block this request.
What if the code doesn't work?
In the list that opens, we're interested in specific parameters that are designated by abbreviations. MB_06 — It shows the state of the battery (Normal, Good, Bad). MB_00, the current percentage of charge, and MF_02 or MF_05, which may indicate the number of charging cycles.
| Parameter | Description | Normal value. |
|---|---|---|
| MB_06 | Battery status | Good / Normal |
| MF_02 | Number of cycles | Less than 500. |
| MF_05 | Real Capacity (mAh) | Close to the passport. |
| MB_00 | Current charge (%) | Any meaning |
Notice the line with real capacity. If your Redmi Note or Mi has a passport capacity of 4,000 mAh and the tester is 3,000 mAh, the wear is 25%. That's a significant loss affecting autonomy.
Analysis through ADB and loggers (for advanced)
For those who are not afraid of the command line, there is a method of obtaining a detailed battery log through ADB debugging, which allows you to pull raw data from system logs that are not displayed in the interface.
First, activate the developer mode. Go to Settings → About Phone and quickly click on MIUI seven times. Once the “You’ve become a developer” notification appears, a new section will appear in the settings menu.
☑️ Preparation for ADB-diagnostics
Connect your smartphone to your computer and type in the command adb shell dumpsys batterystats. You get a huge amount of data. Look for lines that contain currentCapacity or designCapacity. The difference between them is your wear and tear.
⚠️ Attention: Teams ADB Incorrectly entering the reset commands (adb shell dumpsys battery reset) can temporarily disrupt the calibration of the charge indicator, although the data on physical wear will not change this.
The alternative is to use the adb shell cat command. /sys/class/power_supply/battery/capacity in real time while the phone is discharged to plot voltage degradation under load.
Third-party applications for deep diagnostics
If you don't want to mess with codes and command line, specialized applications from Google Play come to the rescue, they read the same system files as the engineering menu, but present them in a convenient graphical form.
One of the leaders in this niche is the AccuBattery application, which does not show instant results when you first start up, you will need to use the phone in normal mode for several days (at least 3-5 charging cycles) for the program to accumulate statistics and calculate the real capacity.
- 📱 Install AccuBattery or Battery Charge Limit.
- 📱 Allow access to usage statistics.
- 📱 Use your smartphone, periodically putting it on charging.
- 📱 After a few days, check the Health tab».
Another popular solution is CPU-Z. The Battery tab will show the current state, manufacturing technology and approximate wear and tear, and the data here is updated in real time, which is convenient for rapid in-store checks when you buy.
It's important to understand that third-party programs run on the Android operating system and can have a 3-5% margin of error, but they're ideal for quick assessment.
Calibration of the battery on MIUI 12
Often the problem is not physical wear, but rather the desynchronization of the charge controller and the software indicator, so the phone can show up to 20 percent and then turn off abruptly, and in such cases, the calibration procedure helps.
The method is to completely discharge the device before turning off, followed by charging up to 100% when off, allowing the controller to re-determine the limits of minimum and maximum voltage.
To perform calibration on Xiaomi:
- Discharge the phone until it is completely turned off.
- Put on charging in the off state to 100%.
- Keep on charging for another 1-2 hours after reaching 100%.
- Turn on the phone without turning off the cable and make sure it is 100% charged.
⚠️ Note: Do not perform a deep discharge procedure more than once in a single session. 3-6 Lithium polymer batteries are not well tolerated by deep zero, which accelerates their chemical degradation.
After calibration, the stats in Settings → The battery should become more accurate and the percentage jumps disappear. If the problem persists, it is likely that the battery cell does need to be replaced.
Factors accelerating battery wear
Understanding the causes of degradation will help extend the life of your Mi or Redmi. The main enemy of lithium batteries is heat. Prolonged heating above 40 degrees Celsius irreversibly destroys the internal structure of the electrolyte.
Frequent charging up to 100% and discharges up to 0% are also harmful. The optimal range for long-term storage of chemical energy is from 20% to 80%. The MIUI 12 shell has a night charging optimization feature that pauses the process by 80% and reaches 100% only before waking up.
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Compliance with the temperature regime and avoiding extreme charge values (0% and 100%) can extend the battery life by 1.5-2 times.
The use of non-original chargers with unstable current also contributes: Cheap cables can cause voltage pulsations that "stress" the power controller.