How to test the battery on Xiaomi Redmi 9: diagnostics and tests

Xiaomi Redmi 9, released in 2020, was powered by a 5020 mAh battery, which was considered the benchmark for autonomy at the time of release. However, over time, lithium-ion cells inevitably degrade, losing some of their original capacity. Owners often notice that the device began to discharge faster, suddenly turn off at 10-15% charge or heat up during charging. These symptoms indicate the need for urgent diagnosis of the state of the power system.

Before you bring your gadget to a service center or buy a new battery, you need to conduct a self-checking software methods, which will allow you to accurately determine the residual life and determine whether you need a replacement or software calibration. In this article, we will look at all the available methods, from built-in engineering menus to third-party utilities.

It is important to understand that software diagnostics does not always show an accurate physical capacity, but it gives a clear picture of the state of the power controller and the chemical composition of the battery. Regular monitoring helps to prolong the life of the device and avoid unpleasant surprises in the form of a sudden shutdown.

Built-in MIUI diagnostics

The easiest and safest way to evaluate is to use a built-in security application from Xiaomi developers, which does not require additional software installation and has access to the basic system indicators. To run the test, you need to open the Security application (green icon with a shield) and scroll down to the Tools section.

In the tool list, you should select Battery or Status, where the system will automatically analyze current processes and energy consumption, and here you will see a consumption chart and a list of leading applications by category. However, this is not enough to get technical data on battery health, so it is worth moving to a deeper test.

Additionally, in the system settings there is a section About the phone, where, when repeatedly pressed on the kernel version or MIUI (It depends on the firmware version, sometimes you open a hidden debugging menu, but the more reliable method is to use it. USSD-codes that operate at the modem level.

• 🔋 Open the standard phone application to dial a number.
• 🔋 Enter the code ##6485## to log into the engineering menu.
• 🔋 Find the parameter. MB_06 (Health Status, which should be "Good".
• 🔋 Check the parameter. MF_05 (Cycle Count showing the number of recharge cycles.

Note that on some global firmware, this code can be blocked or redirected to normal settings, in which case the MIUI security system restricts access to low-level data without root rights.

⚠️ Warning: Do not attempt to change the values in the engineering menu unless you have the appropriate qualifications (MF_05) software without replacing the controller can lead to incorrect display of charge and the risk of fire.

Checking through the engineering menu and codes

If the standard code didn’t work or you want more information, you can use alternative methods to access battery logs. Xiaomi’s engineering menu contains hundreds of parameters, but for a Redmi 9 user, only a few key indicators that reflect the physical state of the cell are important.

Parameter MB_00 The current percentage of the charge is digitally, and MB_01 — current voltage in millivolts. Normal operating voltage is the range of 3700 μ 4200 If you see the values below 3400 mV when the screen is on, this may indicate a deep discharge or a fault of the controller.

It is also worth paying attention to the parameter. MF_02 (Design Capacity, which indicates the design capacity, and MF_06 (Current Capacity: Current Capacity, and comparing these two values gives you an approximate percentage of wear and tear (SOH — State of Health: The difference is more 20% It is time to change the battery.

Use of third-party applications for analysis

When built-in tools are scarce, specialized applications from Google Play come to the rescue, using standard Android APIs to collect statistics and can provide a more user-friendly interface for analysis, and one of the most popular and proven solutions is the AccuBattery utility.

The program is based on real-time monitoring of charge and discharge processes, and to get accurate data, you need to use the application for several days (usually 3-5 charging cycles), and the program collects statistics and calculates the actual capacity, comparing it with the declared manufacturer.

Another powerful tool is Ampere, which focuses on charging speed and consumption currents, and it will help identify problems not only with the battery, but also with the charging cable or power supply, which often affects the perception of autonomy.

• 📱 Install the AccuBattery app from the official store.
• 📱 Allow access to battery usage statistics in Android settings.
• 📱 Complete discharge cycles up to 15% and charge up to 100%.
• 📱 Go to the Health tab to view the wear assessment.

It is important to note that no application has direct access to the battery chemistry without superuser (Root) rights.All readings are calculated based on voltage and voltage, so the error can be 5-10%.

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To improve measurement accuracy in applications like AccuBattery, turn off energy saving while collecting statistics so that the system does not limit background data collection processes.

Analysis of system logs without ROOT-rights

For advanced users who don’t want to install any extra software, there is a method of analyzing system logs through the command line ADB (Android Debug Bridge), which requires connecting a smartphone to a computer and minimal knowledge of working with the console, but gives the most honest data from the core of the system.

First, you need to activate the USB debugging mode. To do this, go to Settings → About Phone and press 7 times on the MIUI Version. Then in advanced settings (Additionally), turn on USB Debugging. Connect the phone to the PC with a cable.

Execute the command to output battery information: adb shell dumpsys battery. In the answer, you will see the lines level (charge level), scale (maximum level), status (charge status) and health (state). Health code 2 indicates good condition, and other values may indicate problems.

adb shell dumpsys battery | findstr"health level"

The good thing about this method is that it reads data directly from the drivers of the Linux kernel on which Android is based, and there's no hard-wrought algorithms from third-party applications, just raw data from the power controller.

Visual and tactile diagnosis

Software methods may not always detect physical defects such as bloating or leakage. Redmi 9 owners should regularly conduct an external inspection of the device, as lithium polymer batteries can release gases when degraded.

Put your smartphone on a flat horizontal surface (table) and try to spin it, and if the case rotates easily around its axis, then the back cover or the battery itself has swelled and created a point of support, which is a critical signal that requires immediate intervention.

Also, look at the back panel: bumps, perimeter adhesives, or body joints diverge are obvious signs of physical battery damage, and in such cases, software testing is no longer meaningful, as the device becomes dangerous to operate.

⚠️ Warning: If you find a battery bloating, immediately stop charging the device.Do not press on the bloating and do not try to pierce the battery, as this may cause a fire or chemical burn.

Additionally, check the charging connector. The loosened micro-USB port (which is used in Redmi 9) can cause poor contact, sparking and local overheating, which the user mistakenly takes for a battery problem.

Calibration of the Redmi 9 battery

Sometimes the battery is physically healthy, but the charge controller does not correctly display the percentages (for example, the phone turns off by 20% or hangs for a long time by 99%), in which case calibration is required - the process of resetting the controller statistics and aligning the voltage values.

The calibration procedure is simple, but it takes time and a full discharge cycle. First, completely discharge the smartphone before automatically turning off. If it turns on again, discharge until it stops responding to the power button.

Then, set the device to charge when it's off. When the indicator shows 100%, don't turn off the cable for another 1-2 hours. Then turn on the phone. If the charge has dropped below 100%, re-connect the charge (without turning off the phone) and reach 100%. Repeat the cycle until after turning on the charge immediately becomes 100%.

This procedure helps the controller to re-remember the limits of minimum and maximum voltage, but if the wear of the physical capacity is large, calibration will not return the lost milliamp hours, but only correct the mapping of percentages.

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Calibration does not restore the chemical capacity of the battery, it only adjusts the software display of the charge level for more accurate operation of the system.

Frequently Asked Questions (FAQ)