Xiaomi and Redmi smartphone owners often experience a device that starts to run out faster than a year after purchase, a natural process of degradation of lithium-ion cells, but it is difficult to understand how critical wear is without special knowledge. Standard indicators in the system show only percentage of charge, hiding the real state of the physical capacity of the battery.
There are several proven ways to diagnose power status, from built-in engineering codes to connecting to a computer, and in this article, we’ll look at how to get accurate data on how many milliamp hours (mAh) your battery can accumulate now, and compare that to factory numbers.
Knowing the actual state of the battery will help you make an informed decision whether to change the battery or limit yourself to software optimization, and ignoring signs of severe wear and tear can lead to sudden shutdowns even at 20-30% charge.
The easiest and safest way to get information about a battery is to use the built-in CIT (Customer Information Test) engineering menu, which is designed for factory testing and contains detailed data on all components of a smartphone, including current charge and voltage.
You don't need superuser rights or PC connection to log in to the menu, just type in a special combination of characters in the Phone app. If the code doesn't work, maybe your version of MIUI or HyperOS has limitations, and then you'll have to use alternative methods.
In the menu that opens, you'll find the battery item, which is usually called the Battery Indicator or simply the Battery, and you'll click on it and you'll see the technical parameters: current voltage, temperature, and most importantly, design capacity.
- 🔋 Design Capacity – the manufacturer’s declared capacity of the new battery.
- 📉 Current Capacity – The current maximum capacity available to the battery.
- ⚡ Voltage - current voltage of the power cell.
- 🌡️ Temperature: Battery temperature at the time of inspection.
⚠️ Note: Do not change the settings in other sections of the engineering menu CIT. Interference with the calibration parameters of the sensor or communication modules can lead to incorrect operation of the device.
What if the code doesn't work?
If you don't get the code anywhere, try dialing it in the phone app instead of finding contacts. CIT It can be closed by the operator.> Checking through hidden USSD-In addition to the full engineering menu, there are shorter codes and commands. USSD-These are commands that display information directly on the screen or allow you to jump to a specific test, which is a quick way to assess the health of the battery without going deep into the technical menus. One of the popular codes for Xiaomi devices is ##6485###. Once you enter it, you open a window with detailed technical statistics, and it is important to pay attention to specific lines, as the number of lines can vary depending on the processor model and the Android version. The key parameter is the string MB_06, It shows the battery status (Good or Bad) and the number of charge cycles. MB_00 or similar, it may display the current charge level as a percentage, and MF_02 (It is worth remembering that on new versions of shells, some codes can be locked or redirected to the standard settings menu, in which case the security system restricts direct access to diagnostic data. If system methods do not give a complete picture, specialized applications from Google Play come to the rescue. It works differently from system utilities: it doesn't just read the controller's data, it calculates the actual capacity by analyzing charging and discharging processes. To get accurate data, the application needs to work in the background for several days. It measures how many milliamp hours were injected into the battery from the moment it started charging to 100 percent, and compares that to the percentage change, and it's based on this statistic to plot the degradation. Other popular utilities, such as Ampere or Battery Guru, also provide detailed information about charge and discharge currents.They are useful for identifying problems with the cable or charger that can indirectly affect the user's perception of capacity. 📊 Cycle analysis – tracking the number of complete recharge cycles. 🛡️ Protection – Notifications of overheating or charging too fast. 📉 History – building a graph of wear and tear for a week or a month. ⚙️ Calibration - help in aligning the percentage of charge readings. ⚠️ Warning: Monitoring applications require constant access to the system and may consume additional charge. It is not recommended to keep them active all the time unless you are actively diagnosing. ADB-The most accurate and professional method of obtaining information is the use of debugging by USB tooling ADB (Android Debug Bridge. This method allows you to pull raw data from the system that is not displayed in the interface, including the exact cycle counter and passport capacity. First, you need to activate the developer mode. Go to Settings → About phone and quickly press 7 times on the item Version MIUI (or OS). Then in the advanced settings, turn on “Debugging by” USB». Connect your smartphone to your computer, install drivers and platform SDK Platform Tools. Open the command line in the tool folder and enter a command to access the shell interface: adb shell dumpsys battery This command will give a brief report on the current status. However, obtaining battery health and capacity data often requires access to system files or the use of specialized scripts that read data from the system. /sys/class/power_supply/battery/. For example, a file charge_full_design It will show the design capacity, and charge_full — current. ☑️ Preparation for ADB-Install Xiaomi drivers Enable debugging by USBAllow access on the phone screen Check the visibility of the device in the command line: 0 / 4 Use of the ADB especially effective when software failures distort the readings in the interface. The command interface gives access to hardware bypassing the graphical shell, allowing you to see the real values of voltage and capacity. The analysis of charging cycles and physical wear The concept of "capacity" is inextricably linked to the number of recharge cycles. The Lithium Polymer and Lithium Ion batteries used at Redmi are considered consumables, and their chemical composition degrades with each cycle, no matter how carefully you treat the device. One cycle is a collection of discharges equal to the same amount of energy. 100% For example, if you've discharged your phone from the battery. 100% before 50%, They were put on charge, and then again discharged to 50%, This will be considered one complete cycle, and usually manufacturers will guarantee that they will be able to maintain their 80% post-container 500-800 Physical wear is not just about shortening the operating time. The old battery can have high internal resistance, which leads to voltage drawdowns under load.The phone can turn off in the cold or when running "heavy" applications, even if the indicator shows 40-50%. The New battery Wear 20% Residual capacity 95-100% 75-80% Less than 70% The number of cycles 0-100 400-600 800+ Behavior in the cold Works stably Fast Discharge Time According to the specification Requires 2-3 charges If the diagnosis shows wear of more than 20-25%, it makes sense to think about the impact of fast charging of the smartphone battery and fast charging the battery. Although power controllers are able to regulate currents, regular use of maximum power (for example, 67 W or 120 W) generates additional heating. High temperature is the main enemy of lithium chemistry. If you often charge your phone during games or navigation, when the body is already hot, the rate of degradation of the capacity increases by many times. The optimal temperature range for charging is 15 to 25 degrees Celsius. Also harmful are the extreme states of charge. Long-term battery stay at 100% (for example, left overnight charging without smart restrictions) or deep discharge at zero contribute to accelerated aging of the battery to a full range of 20%. It is enough to carry out the procedure of resetting statistics (discharge before switching off and charge before the 100% when off) once in 3-6 If you notice a percentage display that is incorrect, is it true that the original charger saves the battery? Yes, the original Xiaomi power supplies have consistent communication protocols with the phone controller. Cheap analogs can deliver unstable current or not turn off the power supply in time, which leads to overheating and accelerated wear. Can you programmatically restore battery capacity? No, the physical wear of the chemical current source is irreversible. Software methods can only calibrate the controller to make the percentages on the screen correspond to the real charge, but they can't add milliamp hours. MIUI The battery lives less? In the first days after a major update, the system performs background optimization of applications and indexing files, which actively consumes the processor and battery life, usually after 3-5 days, the consumption normalizes.