How to check the battery on the Xiaomi phone: from the code *#*#4636#*#*** to disassembling the case

Why does Xiaomi’s battery require more testing than other brands?

Xiaomi, Redmi and POCO are known for their price-performance ratio, but this coin has the flip side: batteries in budget and mid-budget models often fail before the stated deadline. The reason for this is not only natural wear, but also aggressive optimization of MIUI, which forces the processor to work at the limit, as well as cheap power controllers in some lines. For example, owners of the Redmi Note 8 Pro massively complain of battery bloating after 1.5-2 years, and the POCO X3 NFC often drops capacity to 70% over the same period.

The problem is compounded by the fact that Xiaomi does not always honestly display real battery wear in standard settings. So, in the Settings → Battery menu, you will see only an approximate run time, but not an exact percentage of degradation. Meanwhile, timely diagnosis can save you from suddenly turning off your phone for 30% of charge or, in the worst case, from battery bloating, which leads to damage to the screen and motherboard.

In this guide, we will look at 7 ways to check, from hidden engineering menus to disassembly of the case, and tell you what signs indicate an urgent need for replacement. All methods are tested on models from 2019 to 2026 and work independently of the version of MIUI (including HyperOS).

Method 1: Code #4636## - The hidden menu of the battery

The fastest way to get technical information about the battery is to use engineering code, which works on all Xiaomi smartphones without root rights and additional applications.

Instructions:

1. Open the Phone app.
2. Enter the combination: ##4636### (some models may require ##4636*#*#).
3. In the menu that appears, select Battery Information.

In this section, pay attention to the following parameters:

• 🔋 Level of charge (level) – current percentage, should coincide with the indicator in the status bar.
• 🔌 Power source (Power source) - if specified USB or AC, phone charges.
• 📊 Health is the perfect Good value. If you're saying Unknown, Dead or Overheat, the battery requires a diagnosis.
• ⚡ Voltage – should be in the range of 3.7-4.4 V (exact values depend on the model).
• 🔄 Technology (usually Li-ion or Li-polymer.

Try entering the code through the Dial-Up app (not through search).

Make sure that SIM-The card is active (on some models, the code doesn't work without it)

Update MIUI to the latest version

Use the alternative code #284## (for new models)

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Method limitation: ##4636### does not show the actual battery capacity (voltage and state only) and this will require other methods, which we will discuss below.

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If nothing happens after you enter the code, try pressing the call button (green handset).

Method 2: AccuBattery App – Accurate Diagnostics of Wear

The free AccuBattery app (available on Google Play) is one of the most reliable tools for monitoring battery health, and unlike standard MIUIs, it shows real wear in percentages rather than rough data.

How to use:

1. Download and install AccuBattery.
2. Launch the app and provide all the necessary permissions (especially access to battery statistics).
3. Charge your phone from 0% to 100% without interruptions (important for calibration).
4. After full charging, go to the Health tab.

What do indicators mean?

• 📉 Battery wear – if the value exceeds 20-25%, it is time to change the battery.
• ⚡ Estimated capacity – compare with passport capacity (for example, for Redmi Note 11 it is 5000 mAh).
• 🔥 Temperature - optimal range of 20-40°C. Exceeding 45°C critically.
• 🔄 Charging cycles – after 500 cycles, the capacity usually drops by 20-30%.

Once a month

Every 3-6 months

Only when the problems start.

Never calibrated.

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The advantage of AccuBattery is that it keeps statistics on each charging cycle and warns of bad habits (for example, constant charging up to 100%).

Method 3: ADB Test for Advanced Users

If you are ready to use a computer, the method is ADB (Android Debug Bridge will provide the most accurate data about the battery, which is suitable for models where access to the engineering menu is blocked or you need advanced settings.

What you need:

• 🖥️ Computer with Windows/macOS/Linux.
• 🔌 USB-cable (preferably original).
• 📥 Established ADB-driver.
• 📱 Included debugging by USB on the phone (Settings) → The phone. → Version. MIUI → 7 times to tap according to the version → return to additional settings → For developers → Debugging by USB).

Instructions:

1. Connect your phone to your PC and open the command line (or terminal).
2. Enter the command to check the connection: Adb devices should appear the name of your device.
3. Execute the command to obtain battery data: adb shell dumpsys battery

Decoding of key parameters:

Warning: If the health parameter is 3 (bad condition), 4 (overheating) or 7 (unknown error), the battery should be replaced soon.

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ADB-Checking is the only way to know the real capacity of the battery (capacity parameter) without disassembling the phone.

Method 4: Physical examination – when to disassemble the phone?

If software methods show critical errors or the phone suddenly turns off, you have to inspect the battery visually, and battery bloating is the most dangerous malfunction that can damage the screen or even cause fire.

Signs that it is time to take out the phone:

• 📱 The screen began to "step away" from the body (see a gap on the edges).
• 🔄 The phone is not flat on the table (swings due to bloating).
• 🔋 The battery discharges quickly even after replacement (may indicate damage to the controller).
• 🔥 The body is noticeably heated in the area of the battery.

How to inspect the battery:

1. Turn off the phone and remove the tray. SIM-map.
2. Put the back cover with a plastic blade (on models with a non-removable cover, for example, Xiaomi 12, you will need a hair dryer to soften the glue).
3. Carefully disconnect the battery plume (do not pull the wires!).
4. Examine the battery for the subject: 🔍 Bloating (normal battery flat, without bulges). 💧 Electrolyte stains (white or green plaque). 🔥 Burns or blackening.

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If the battery is swelling, do not try to pierce or bend it, this can lead to fire, it is better to dispose of it immediately at a special reception point.

Important: After disassembly, check the integrity of the power controller (a small chip next to the battery connector) if it is damaged, the new battery may not work.

Method 5: Multimeter Test for Maximum Accuracy

If you have a multimeter, you can measure the voltage and resistance of the battery to millivolt precision, which is a method that can be used to test both removable and built-in batteries.

What you need:

• 🔧 Multimeter (even budget for 300-500 rubles).
• 🔌 Tweezers or thin wires for connection.
• 📱 Disassembled phone (or battery removed from device).

Instructions:

1. Transfer the multimeter to DC voltage measurement mode (DCV 20V).
2. Connect the black probe to the battery's negative contact, the red probe to the plus one.
3. Take a note of the statement. Compare it to the table:

If the voltage is below 3.0 V, the battery is in a deep discharge state and may not be charged with a standard charger, in which case a booster (a device for "resuscitation" of batteries) will be required.

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The multimeter will show the real voltage, which can differ from the data in MIUI by 0.1-0.3 V. This is important for diagnosing the power controller.

Method 6: Checking through MIUI Diagnostics (hidden utility)

MIUI 12-14 and HyperOS have a hidden utility called MIUI Diagnostics that allows you to test the battery without third-party applications, and it's not available on all models, but it's worth a try.

How to start:

1. Open the Settings. → The phone.
2. Tap 5 times on the item MIUI version (should appear message "You became a developer").
3. Return to the main settings and open Additional settings → For developers.
4. Find MIUI Diagnostics (CIT or Factory Test).
5. Select Battery Test.

What the utility checks:

• 🔋 Capacity - compares the current capacity with the passport.
• ⚡ Charging/discharge current – if the values are very different from the norm, the problem is in the controller.
• 📊 Charging cycles – shows the number of full discharges.

Restriction: Some models (e.g. POCO F3) may not have a utility or require a password.

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If MIUI Diagnostics has a Charge Test, run it – it will show how fast your phone is charging compared to the reference values.

Method 7: Indirect assessment (without tools)

If you don't have a cable or a multimeter on hand, you can measure the battery status of the phone, and these are not accurate numbers, but they can help you understand that something is wrong with the battery.

Disturbing symptoms:

• ⚡ The phone turns off at 20-30% of the charge (they say incorrect calibration or wear).
• 🔥 The body heats up strongly when charging or playing (especially in the area of the camera).
• 📉 Charge drops 10-15% in 10-15 minutes without loading.
• 🔌 Charging is jerky (fast, then slow) or stops at 80-90%.
• 📱 The phone does not turn on after full discharge (even after connecting to charging).

What to do:

• 🔄 Try calibrating the battery: completely discharge the phone, then charge to 100% without interruption. Repeat 2-3 times.
• 🧹 Clean the dust charger connector (use a toothpick or compressed air).
• 🔧 Update the firmware - in new versions MIUI Frequently correcting food management errors.

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If the phone is turned off at 30-40% of the charge, but after restarting shows a normal level, the problem is more likely in the power controller, not in the battery itself.

FAQ: Frequent questions about Xiaomi battery check