How to find out the real capacity of Xiaomi battery

Xiaomi’s smartphones, including Redmi and POCO, are known for their high autonomy, but over time, any lithium-ion power source degrades. Users often notice that the device starts to run out faster or turn off at 20% charge, indicating a decrease in actual capacity. Standard MIUI or HyperOS operating system tools do not provide direct access to the “battery health” indicator in an understandable form, hiding this data in system logs.

A combination of software techniques and engineering codes is needed to make a precise diagnosis. The nominal capacity listed on the case or in the specifications is often different from the amount of energy a battery can actually store after hundreds of charging cycles. In this article, we will look at proven ways to get reliable information about the state of your battery, from simple settings to in-depth system analysis.

Understanding the current state of the chemical current source will help you decide whether to replace or calibrate. Ignoring signs of severe wear can lead to a bloating of the battery or sudden shutdowns at the most inopportune moment. We will look at methods that do not require root rights, as well as advanced options for power users.

Use of the engineering menu USSD-code

The fastest way to access hidden diagnostic information is to use special information. USSD-In Xiaomi smartphones, the main tool is the engineering menu, which opens through a standard call. Type the code ##6485##, and a list of technical parameters will appear on the screen.

The interface of this menu may vary depending on the firmware version. MIUI If the code didn't work right away, try an alternative ##4636##, Although it's more commonly used to configure networks, in the list that you open, look for parameters that start with a prefix. MB_.

• 🔋 MB_06 — displays the current state of the battery (Good, Bad, Overheat).
• 📊 MB_00 — total percentage of charge at the moment.
• ⚡ MB_01 — current battery voltage in millivolts.
• 📉 MF_02 — Number of full recharge cycles (Cycle Count).

It's important to note that not all models support the output of full information through this menu (RF_BM) It can be hidden or replaced by zero, and then the system simply doesn't read that data through the standard interface gateway.

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If the ##6485### code doesn’t work, try entering it in the Phone app via the dialer, not through a search in the settings.

Particular attention should be paid to the parameter MF_02. If the number of cycles exceeds 500-800, And autonomy has fallen, which is a direct sign of physical wear and tear. 800 full-cycle 20% container.

Analysis of the system file battery_history

The Android operating system keeps a detailed log of all components, including power consumption. battery_history.txt It contains raw data that can be analyzed to identify problems, and accessing this file requires a superuser's (Root) rights or use. ADB (Android Debug Bridge from your computer.

Once you get a file, it looks like a set of numbers and codes that the average user doesn't understand. There are online services and desktop utilities like Google's Battery Historian to decrypt, and if you upload the log, you get a discharge graph to the right second.

⚠️ Attention: File battery_history.txt It may contain sensitive information about the time of use of applications. Do not transfer this file to unauthorized persons or upload it to dubious resources.

Log analysis allows you to see which process or application is causing the parasitic discharge. It often happens that after a system update, the background service starts consuming a disproportionate amount of energy, which is mistakenly perceived as battery wear. In reality, the battery may be fine, and the problem lies in the software.

Applications for monitoring the status of the AKB

If you don't want to mess with logs and codes, Google Play's specialized apps come to the rescue, and they read data from the system power controller and interpret it into a clear graph, but it's worth remembering that without root rights, these programs only see what the system allows.

One of the most popular tools is CPU-Z or AIDA64. In the Battery section, these utilities show the current state, technology, voltage and, most importantly, the estimated capacity. Compare the Charge Counter score to the factory specifications of your model.

Another useful application is AccuBattery, which is that it doesn't show data instantly, but it collects statistics as you go about it. To get an accurate result, you need to run several charging cycles from the computer. 15% before 80-90% run-up.

Optimizer applications often promise to "restore" the battery, but that's a marketing ploy. Physical wear repair is impossible. It only closes the background processes, temporarily improving autonomy, but doesn't change the chemical composition of the electrolyte.

Checking through computer and ADB utilities

For PC users, the most accurate method is to use a debugging bridge. ADB. This method allows you to access system files without having to install apps on the smartphone itself. USB and installed Xiaomi drivers on your computer.

Once you have activated the debugging, execute the command to output battery information. In the terminal (CMD or PowerShell), type:

adb shell dumpsys battery

This command will give you your current status, charge level and health status, but you can use the command to get more information about the actual capacity:

adb shell cat /sys/class/power_supply/battery/capacity

If the device supports reading the full passport capacity, you can try requesting a file. charge_full or charge_full_design. The difference between these values will show the percentage of degradation. Unfortunately, on many modern Xiaomi models, access to these files is closed at the kernel level without root rights.

⚠️ Note: Do not enter commands that you do not understand, especially those that start with setprop or rm. This can lead to system instability or data loss.

Visual diagnosis and calibration

Sometimes software methods show conflicting data, and then the good old empirical method comes to the rescue: visual diagnostics involves examining the case for bloating and testing the behavior of the phone under load. If the back cover has moved away or the screen has begun to bend, the battery must be changed immediately.

Calibration of the charge controller can help if the percentages on the screen are not displayed correctly (for example, phoned from 30% to 5%). To do this, completely discharge the device before turning off, then set the charge off to 100% and hold on power for another hour.

• 🔌 Discharge the phone before automatically shutting down.
• 🔋 Charge the device off to 100%.
• ⏳ Leave it on the charger for another one. 1-2 half-hour.
• 🔄 Perform a forced reboot (power button 10 seconds).

This procedure resets the controller and recalibrates the percentage scale, and it doesn't restore the physical capacity, but it makes the charge map more linear and predictable, and it doesn't make sense to repeat the procedure more than once every few months.

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Calibration only helps with the desynchronization of the controller and the real charge, but does not treat a physically worn-out battery.

Frequent questions about Xiaomi’s battery capacity