How to check the battery status on Xiaomi Redmi 8: all ways

The battery is one of the most vulnerable parts of the Xiaomi Redmi 8, especially after 2-3 years of active use. If your smartphone starts to run out in a few hours, turn off 20-30% of the charge or overheat when charging, the problem is likely to lie in the battery.

In this article, we will discuss 5 proven ways to diagnose a battery, from hidden engineering menus to specialized applications, learn how to interpret mV, mAh and charging cycles, and what to do if the battery is worn out by 50% or more. All methods are tested on the Redmi 8 with MIUI 12-14 and are relevant to the Redmi 8A/8A Pro models.

1. Checking with code ##4636##

The fastest way to get basic information about a battery is to use service code, which runs without root rights or additional applications, but shows limited data.

Instructions:

1. Open the Phone app.
2. Enter the combination: ##4636###.
3. In the menu that appears, select Battery Information.

In this section you will see:

• 🔋 Charge level (%): current percentage, but it may not match the one displayed in the status bar.
• 🔌 Status: Must be Charging or Discharging. If stated Unknown, this is a sign of a controller malfunction.
• ⚡ Voltage (mV): Normal for the Redmi 8 - 3700-4200 mV at 100% charge. values below 3500 mV at 20% charge indicate severe wear and tear.
• 🌡️ Temperature (°C: optimally 25-35°C. Exceeding 40°C when charging - cause for concern.

💡

If the code doesn’t work, try entering it through Google’s Dial (install from Play Market) app.

Limitations of the method:

• ❌ Does not show real capacity (mAh) - only percentage.
• ❌ No data on wear (charging cycles).
• ❌ Some of the menus may not be available.

2. Hidden Engineering Menu (MTK Engineer Mode)

The Xiaomi Redmi 8 is built on a Qualcomm Snapdragon 439 processor, but it has a hidden battery diagnostic menu available through the MTK Engineer Mode app. Despite the name, it works on Qualcomm devices as well.

Step-by-step:

1. Download MTK Engineer Mode from Play Market.
2. Open the app and go to the MTK Settings section.
3. Select Battery (can be called Battery Info or Power).

Here you will find the extended data:

🔍 Important nuance: Battery Health may not display correctly on custom firmware. If it's 0% or 100%, use other methods.

High voltage at 100% charge (more than 4.3V)|Low capacity (less than 3000 mAh)|Temperature above 38°C when charging|Health status below 70%-->

Applications for diagnostics (AccuBattery, CPU-Z)

Specialized utilities give the most complete picture of the battery status. We recommend two proven tools:

1. AccuBattery (free, no root)

• 📊 Shows real capacity (mAh) and wear (%).
• 📈 Builds discharge and charging schedules.
• ⚠️ Requires calibration: Use it 2-3 Full charge/discharge cycle for accurate data.

2. CPU-Z (Battery section)

• 🔋 Displays Level (%), Voltage (mV), Temperature (°C).
• 📱 Health (state) and Technology (type of battery).
• ❌ Doesn't show capacity in mAh.

📌 How to interpret data?

• 🔄 Charging cycles: more than 500 cycles - a reason to replace.
• 📉 Capacity: if the actual capacity <60% factory-wise (4000 mic → <2400 mAh), battery critically worn.
• ⚡ Discharge speed: >10% per hour on standby – a sign of malfunction.

AccuBattery|CPU-Z|MTK Engineer Mode|Other |Not checking-->

⚠️ Note: Some applications (e.g. Battery) HD) Incorrect data on Xiaomi due to specific features MIUI. Use only the verified utilities.

4. Check through ADB (for advanced users)

If you want the most accurate data, you can use ADB (Android Debug Bridge), which requires a connection to a PC, but gives you access to hidden system parameters.

Instructions:

1. Install ADB Tools on your PC.
2. Turn on USB Debugging on your phone (Settings → About Phone → MIUI Version → 7 times press to unlock Developer Mode).
3. Connect your phone to your PC and execute the command:

adb shell dumpsys battery

In conclusion, note:

• level: current charge (%).
• Voltage: Voltage (μV, divide by 1000 for mV).
• temperature: temperature (tenths of the value) °C, divide by 10).
• Health: condition (2 = good, 3 = bad).

🔍 Example of inference:

level: 78




Voltage: 3850000 (3850 mV)




temperature: 320 (32°C)




health: 2

⚠️ Warning: If health: 3 or voltage is much lower than normal, the battery needs to be replaced.

5. Visual examination and physical diagnosis

If the software methods show problems, but you want to be 100% sure, you'll have to disassemble the phone. It's an extreme method, but it gives the most accurate picture.

🔧 What to check:

• 🔋 Battery bloating: If the phone's body is curved or the screen is "going away" - it's a sign of bloating!
• 🔌 Contacts: Oxidation or contamination of battery contacts leads to poor charge.
• 📏 Thickness: Compare with the new battery (thickness of the new battery) ~4 mm).

⚠️ Note: when disassembling Xiaomi Redmi 8 easily damage the plume of the fingerprint scanner or camera.

📌 How to safely remove the battery:

1. Turn off the phone.
2. Heat the back cover with a hair dryer (60–70°C) to soften the glue.
3. Use a plastic shoulder blade to gently tuck the cover.
4. Disconnect the battery plume before it is removed.

💡

If the battery is swelling, DO NOT try to puncture or compress it! This can cause a fire or explosion.

Calibration of the battery (if the data are inaccurate)

Sometimes the system will not display the charge level correctly because of a controller failure, and calibration will help.

🔄 Step-by-step instruction:

1. Charge your phone to 100% and keep charging for another 1-2 hours.
2. Turn off charging and use the phone until it turns off automatically.
3. Connect the charger and charge up to 100% without turning on the phone.
4. Turn on the device and check the data through AccuBattery.

⚠️ Attention: calibration only helps with software failures, not physical wear and tear. If the actual battery capacity has fallen, this method will not return it.

📊 When calibration is useless:

• 🔋 The battery swelled.
• 📉 Real capacity. <50% factory-wise.
• ⚡ The phone is turned off at 30-40% charge.

Frequent Questions (FAQ)