Modern smartphones Xiaomi, Redmi and POCO are famous for their autonomy, but over time, even the most capacious battery loses its original properties. Users often notice that the device begins to discharge faster, holds a charge for a long time at the beginning or, conversely, suddenly turns off at 15-20%. These are direct signals that the physical wear of the battery is already significant, and it is time to conduct a detailed diagnosis.
Unlike iOS, where Apple has incorporated a clear percentage of battery health into its standard settings, Android’s basic operating system hides this information. MIUI shell or its successor HyperOS also has little time to show users accurate data on the number of recharge cycles or residual capacity in milliamp hours. However, this data exists in system logs and is accessible through special engineering codes or software interfaces.
In this article, we will discuss in detail all available methods, from simple USSD-You'll learn how to distinguish a calibration software failure from a real degradation of a Li-Pol element and whether to change the battery right now.
Use of the Engineering Menu through USSD-code
The fastest and most affordable way to access diagnostic data is through hidden engineering menus. Xiaomi smartphones have several combinations that open up service functions. The most common code to check battery status is ##6485##. By entering it in the Phone app, you will instantly go to the Battery Info menu.
There are a lot of options that are displayed here, but not all of them are useful to the average user. Some values can be empty or show zeros if the firmware is not transmitting data from the power controller. It is important to pay attention to specific strings that have numerical values. If the menu does not open, perhaps your firmware version blocks this code, and then you will need to install a third-party caller application.
⚠️ Note: Enter codes carefully. Trying to change the settings in other sections of the engineering menu (for example, ##4636##) without understanding their purpose can lead to loss of network signal or unstable operation of communication modules.
To interpret the data correctly, you need to understand what the key abbreviations mean. Below is a table decoding the main parameters that you will see on the screen:
| Parameter | Description | Normal value. |
|---|---|---|
| MB_06 | Battery status | Good |
| MB_00 | Current charge (%) | 0-100% |
| MB_01 | Current voltage | 3700-4400 mV |
| MF_02 | Number of complete cycles | Up to 500-800. |
| MF_05 | Residual capacity (mAh) | Close to the passport. |
Particular attention should be paid to the parameter MF_02, This is a collection of full charge cycles, and lithium polymer batteries retain optimal properties until about the same time. 500 After the cycles. 800 And the degradation is noticeable even without any tests. 1000, The battery has run out of life.
What if the code doesn't work?
Decoding of parameters MB_06 and MF_05
Parameter MB_06 It's an indicator of the overall state of the battery. Ideally, it should say "Good." If you see "Bad," "Overheat," or "Over Voltage," it indicates critical problems. However, the power controller may not immediately respond to physical wear and tear, continuing to show "Good" even if the actual capacity has dropped to the same level. 60% nominally.
A more informative parameter is MF_05 (sometimes MF_06 It's based on the model, which shows the current calculated capacity in milliamp hours, and compare that number to the passport capacity of your model, for example, if you have a Xiaomi Redmi Note. 10 battery 5000 mAh, and the menu shows 3200,, and the wear is more than 35%, That is already a reason to replace.
It's important to understand the difference between the current charge and the full capacity. The current charge shows how much energy is left right now, and the parameter is the current charge. MF_05 — How much energy a battery can hold theoretically at full charge is the second value that characterizes battery health.
- 🔋 If MF_05 absent or equal 0, The system cannot read data from the controller. BMS.
- 📉 Meaning MB_06"Good at low MF_05 The battery is intact but physically worn out.
- 🔥 Overheat status requires immediate cessation of use and bloating checks.
💡
Parameter MF_05 — It’s the only way to find out the real residual capacity without a computer connection, but it’s not available on all smartphone models.
Don't just rely on interest, even if the phone shows you. 100% charge, but MF_05 So much less than the factory value, and the operating time will decrease in proportion to the drop in capacity, and this is not a software bug, but a physical feature of the aging of chemical elements.
Checking through ADB and Command Prompt
For those who want to get the most accurate and complete data that is not available in the usual menu, there is a method using USB debugging (ADB), which allows you to extract raw data from the system files Battery Stats, which store the history of use and accurate measurements of voltage and capacity.
To start, activate the developer mode. Go to Settings → About Phone and 7 times click on the MIUI version. Then in the advanced settings, turn on "Debugging over USB." Connect your smartphone to your computer and use the following command to obtain battery status:
adb shell dumpsys batteryThis command will give you a brief account of the current state of charge, connection status, temperature and voltage. However, to get information about charging cycles and health, you often need access to system files, which may require root rights. In modern versions of Android, access to these files is limited, but the dumpsys command often shows a charge counter parameter that can be compared to passport capacity.
☑️ Preparation for diagnosis through ADB
If the standard command does not give the necessary detail, you can request information about the properties of the battery through getprop, although this does not work on all firmware:
adb shell getprop | grep batteryUsing ADB is safe for user data, as we only read information. However, you should not enter commands to reset statistics (adb shell dumpsys battery reset) unless you plan to recalibrate the charge controller, as this can temporarily disrupt the correct display of interest.
Third-party applications for accurate diagnosis
When built-in tools are limited, specialized applications from Google Play come to the rescue, and AccuBattery has been a leader in this field for many years, and its principle of operation is based on monitoring the charging process: the application measures how many milliamp hours were “filled” in the battery from the moment of charging to 100%, and compares this with the manufacturer’s stated value.
Importantly, AccuBattery doesn't know your battery capacity initially, and it takes several charging and discharging cycles (usually 3-5 full cycles) to accumulate statistics and get a reliable health percentage, so don't be afraid if, after the first installation, the app shows odd numbers or 100% health on an old phone.
- ⚡ AccuBattery – shows the real capacity, wear rate for charging and consumption of applications.
- 📊 CPU-Z — Provides detailed technical information about iron, including voltage and temperature in real time.
- 🔍 Battery Charge Limit is an advanced application for those who want to limit their charge (for example, up to 80%) to extend the life of the battery.
Other applications, such as Ampere, are useful for checking the quality of the charger and cable. They show the current of charge and discharge. If the original charger is connected significantly lower than the stated current (for example, 0.5A instead of 2A), the problem may not be in the battery, but in the accessories or charging connector.
💡
For the most accurate readings in AccuBattery, discharge your phone to 15-20% and charge up to 90-95% in off or in flight mode to minimize background losses.
Don't install many of these utilities at once. They can conflict with each other, requesting access to the same system resources, which will lead to increased battery consumption and distortion of measurement results.
Visual Diagnostics and Indirect Signs
Software is good, but the physical state of the battery is often more telling than any number. Lithium polymers are often degraded by changes in their physical properties. The most dangerous sign is bloating. If you notice that the back of the phone has started to move away, the screen has risen or the phone has stopped lying flat on a flat surface and swings when you press the corner, the battery needs to be changed immediately.
Bloating occurs because of the release of gases inside the cell when the electrolyte is broken, and it's dangerous to use such a device, because if you're under a lot of mechanical stress or overheating, you can heat acceleration and ignition, and no amount of software resets can help.
⚠️ Warning: If you find bloating, do not try to puncture the battery or press hard on the screen to "set" it in place.
Indirect signs of wear also include unstable voltage, the phone may show 30% charge and suddenly turn off, or, if you charge the phone at 20%, it will show 80% after 5 minutes, which suggests that the charge controller cannot correctly count the residual capacity due to a strong change in the internal resistance of the cell.
Another marker is heating. If the phone warms up in the battery area when performing light tasks (browsing, messengers), it is a sign that the efficiency of chemical reactions has fallen, and most of the energy is spent in heat, not in the operation of the device.
Battery calibration: myths and reality
Often, users notice that percentages are not displayed correctly, and calibrate the method, which is simple: discharge the phone to zero (before turning off), then charge to 100% when it is turned off, without interrupting the process, which is believed to help the controller re-determine the limits of capacity.
But it's important to understand that calibration doesn't restore the physical capacity of the worn-out battery, it only corrects the software display scale. If the battery has degraded to 3,000 mAh, calibration won't make it 5,000 mAh, it just makes the percentages appear linearly relative to the new 3,000 mAh.
Full calibration (deep discharge) is often not recommended for modern Li-Pol batteries. Deep discharges below 2.5-3.0 volts per cell can cause irreparable chemical damage, finally finishing the battery. Do this only if percentage surges have become critically interfering with use.
💡
Calibration solves the problem of “jumping” percent, but does not prolong the life of a physically worn-out battery.
The best “calibration” strategy is normal operation. The BMS controllers in Xiaomi smartphones are smart enough to adjust readings in the background on their own. It is enough to simply use the phone in normal mode, avoiding extremes of 0% or 100% charge for a long time.