How to find out the real status of the battery in Xiaomi

Xiaomi smartphones are famous for their balance between performance and autonomy, but over time, any lithium-ion battery inevitably degrades. Users often notice that the device, which previously worked quietly for a day and a half, now discharges by lunch or suddenly turns off at 20% charge. Understanding the real state of the power unit is the first step to solving the problem, whether it is a software calibration or replacing a physical part.

The Android operating system that runs the MIUI or HyperOS shell doesn’t have a single “Show battery health” button, as it does in iOS. However, the Chinese company’s engineers have left behind many hidden tools and logs that provide comprehensive information, and in this article we’ll look at all the diagnostic methods available, from simple codes to deep analysis of system files.

Before you start to do complex manipulations, it's important to realize that software methods only give a rough estimate based on the calculations of the power controller. To obtain legally relevant data or accurately determine residual capacity, hardware diagnostics is often required, but for household use, digital metrics are quite enough. Let's look at how to extract this data as efficiently as possible.

Using the CIT Engineering Menu for Diagnostics

The fastest and most reliable way to evaluate a smartphone is to access the CIT (Customer Interface Test) hidden engineering menu, which is designed for factory testers and allows you to check the operation of all smartphone modules, including the battery, which is closed to the average user, but opens through a special set of characters in the phone book.

To log in, you need to open the standard Phone app and dial the combination ##6484##. If the code is entered correctly, the test list will instantly open on the screen. We are interested in the item related to the battery (usually called Battery Indicator or simply Battery), which displays the current parameters: voltage, temperature and, most importantly, status.

Some versions of MIUI firmware on this menu show you the "Battery Health" line or wear percentage, but it's worth remembering that not all models support output of this information in the CIT GUI. If you only see current charge and voltage, then your model needs a deeper analysis through system logs or third-party software.

⚠️ Warning: Be extremely careful in the engineering menu. Do not press the Pass or Fail buttons unnecessarily and do not select items related to cleaning memory (Clear Data) or calibrating the sensor if you are not sure of your actions. This can lead to resetting important settings.

The engineering menu is a powerful tool, but it only shows a snapshot of the current state, and other methods are better used to track wear patterns, which we will discuss later.

Verification through hidden system commands

If the standard menu CIT If you don't get the full picture, you can try to address the deeper levels of the system through USSD-One of the most popular codes for Xiaomi devices is ##4636##. It opens the Check menu, where you can select the Battery Information section».

The window that opens displays detailed statistics: charge level, scale, health status (Health), technology (usually Li-polymer), voltage and temperature. The Battery Health field is key: the Good value means that the battery is normal, and Bad or Overheat signal critical problems.

However, on current versions of Android (11, 12, 13 and later), access to this menu is often blocked by the manufacturer for security reasons. If nothing happens when you enter the code, try an alternative method through the Test Mode app, which is sometimes preinstalled on the system.

It's important to understand that commands give access to the power controller (PMIC) data, which can be wrong in the calculations if the calibration has not been done for a long time, so the data in this section should be taken as reference.

System Log Analysis through ADB (For Advanced)

The most accurate method, which does not require superuser rights (Root), but requires a computer and cable, is to analyze system logs through the ADB (Android Debug Bridge) debugging bridge, which allows you to pull raw data about charging cycles and real capacity from the system, which are stored in the kernel files.

To start, activate the developer mode on your smartphone. Go to Settings → About Phone and quickly press 7 times on the MIUI Version (or OS Version). Then go to Settings → Advanced Settings → For Developers and turn on the USB Debugging Toggle.

Connect your phone to your computer, install ADB drivers, and open the command line. Enter the following command to get battery data:

adb shell dumpsys battery

This command will display the current status, but to obtain the wear history and design capacity, you will need to analyze the log. battery_history.txt Or use specialized scripts that parse the output of the dumpsys command. In the output, look for parameters related to charge counter (current charge in mAh) and design capacity (design capacity).

By comparing the current maximum capacity (which can be calculated by fully charging the device and looking at the final meter) with the factory, you can get an exact percentage of wear and tear, which is the most professional method of software diagnostics.

Third-party monitoring applications

For those who don't want to mess with the command lines, there are many Google Play apps that can read data directly from the power controller, and AccuBattery is the leader in this field, not only showing the current charge, but also analyzing each charging cycle in the background, gradually calculating the actual battery capacity.

The way these applications work is by comparing the amount of energy that is poured into the battery per cycle to the percentage of charge gain. After several charging-discharge cycles, the program will produce a fairly accurate health score (Health) as a percentage. Other popular applications include Battery Charge Limit (to limit charge) and Cpu-Z (to view general information about iron).

However, without Root rights, many applications have limited access to system files and can only show approximate values read from the standard Android API. However, for household use, their accuracy is usually enough to determine whether to change the battery.

Using third-party software is the easiest way for the average user to get an answer to the question about the state of the battery without the risk of breaking something in the system.

Interpretation of indicators and rate of wear

After receiving the data on the state of the battery, many users panic when they see the numbers below 100%. It is important to understand the physics of lithium-ion batteries: they are consumables. It is normal to reduce the capacity to 80% after 500 full charging cycles (about 1.5-2 years of active use).

If you're measuring 90-95%, that's a good condition for a device over a year old. If you're reading 80-85%, you're seeing a noticeable but comfortable wear, you can use a little less, but you can hold a load, and you're thinking of a 70 percent or lower threshold, which is critical, and you might have sudden shutdowns in the cold or under load, and you might have a bloating element.

Also worth paying attention to the voltage spread between the cells (if you have a dual-cell battery, which is often the case in flagships with fast charging 120W+). A large difference in voltage can indicate a malfunction of the controller or one of the cells, which requires service intervention.

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To extend your life, try not to drain your phone to zero or charge at 100%, and the optimal range for lithium is 20% to 80%.

Battery calibration: myths and reality

Often, users, when they find a discrepancy between the percentage on the screen and the actual behavior of the phone, try to do a "calibration." The essence of the method is simple: discharge the phone before turning off, charge to 100% when it's off, and lie down for another hour. Then turn on and use as usual.

This procedure helps to reset errors in the batterystats.bin file, which stores usage statistics. It can fix the situation when the phone turns off by 15% or shows 100% and immediately drops to 90%. However, calibration does not restore the physical capacity of the battery. If the chemistry has deteriorated, no dancing with a diamond will return the lost milliamper-hours.

Full calibration is often not recommended, as deep discharge is harmful to modern Li-Pol batteries, only if there are obvious glitches in the percentage of charge display.

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Calibration only corrects the percentage display on the screen, but does not treat physical wear and tear of the battery.

FAQ: Frequently Asked Questions