The battery is one of the most vulnerable components of the smartphone, and the Xiaomi Redmi Note 8 is no exception. Over time, the battery capacity decreases, the device begins to discharge faster, and in some cases even turns off at 20-30% charge. If you notice these symptoms, it’s time to diagnose the battery condition. In this article, we will analyze all the available ways to check the battery on the Redmi Note 8 — from built-in MIUI tools to hidden engineering menus and third-party applications.
It's important to understand that battery wear is not just the percentage of residual capacity, but also the number of charging cycles, the operating temperature, and possible software errors. For example, after the MIUI update, some users experience incorrect display of the charge level, we will show how to distinguish real wear from software failure and what to do in each case.
Before you start diagnosing, make sure your Redmi Note 8 is at least 20 percent charged, and some testing methods require a charger to be connected, and abrupt power outages during tests can cause the battery controller to malfunction.
1. Check the battery through the MIUI settings (official method)
The easiest and safest method is to use the built-in MIUI tools, which require no additional applications and is suitable even for inexperienced users, but it is worth considering that the data here can be inaccurate due to system optimizations.
To get basic information about the battery:
- Open the Settings. → The phone.
- Tap a few times on the MIUI version until you become a developer!
- Return to the main settings menu and select Additional → For developers.
- Find the Battery Status section (on some versions of MIUI it may be called Battery Information).
Here you will see two key parameters:
- 🔋 Charge level – current percentage in real time.
- 🔄 Condition – usually displayed as Good, Medium, or Bad (based on the number of charging cycles).
Unfortunately, this menu does not show the actual battery capacity in mAh, and the assessment of the condition is often subjective. For example, a battery with a 30 percent wear may show a good status if the number of charging cycles has not yet exceeded a threshold.
⚠️ Note: Some Redmi Note 8 firmware (especially global versions) may not have a Battery Status section, in which case use alternative methods from the following sections.
2. Hidden Engineering Menu: Code ##4636## and its features
More information can be obtained through the Android engineering menu, which works on most Xiaomi smartphones, including the Redmi Note 8, but requires caution – do not change the settings unless you are sure of their purpose.
Instructions for opening the menu:
- Open the Phone app.
- Enter the combination: ##4636## (no spaces).
- In the window that appears, select Battery Information.
In this menu you will see the following data:
- 📊 Charge level - percentage with an accuracy of tenths.
- 🔌 Power supply - Battery, USB or AC (if the charger is connected).
- 🌡️ Temperature is a critical parameter. Normal: 25-40.°C. If the value exceeds 45°C, battery overheats.
- ⚡ Voltage - should be in the range of 3.7-4.4 V when fully charged.
Note the battery health parameter (if any) on some firmware here, which shows real wear as a percentage, for example, 85% means that battery capacity has decreased by 15% from the original.
Temperature (not higher than 45°C)
Voltage (3.7-4.4 V at 100% charge)
Power supply (must be in accordance with current condition)
Charge level (compare with the indicator in the status bar)-->
⚠️ Warning: If the battery temperature is constantly above 40°C even without active use, this may indicate a malfunction of the battery or charging controller.
3.Use of the AccuBattery application: accurate diagnosis of wear
To get the most accurate data on the status of the battery, we recommend installing a third-party application AccuBattery, which analyzes charging cycles, measures real capacity and predicts the remaining battery life.
How to use AccuBattery on Redmi Note 8:
- Download the app from Google Play.
- Provide all the necessary permissions (access to battery statistics and notifications).
- Charge your phone to 100% and wait for AccuBattery to collect data (usually 2-3 charge cycles are required).
- Go to the Health tab to see the current wear and tear.
In the annex, note:
- 📉 The estimated capacity is the actual battery capacity in mAh. For the Redmi Note 8, the nominal capacity is 4000 mAh. If the value is below 3200 mAh, the battery is severely worn out.
- 🔄 Number of charging cycles, the more, the more wear and tear. Normal: up to 500 cycles.
- ⚡ Charging/discharge speed – useful for identifying background processes consuming charge.
AccuBattery also shows the predicted lifetime at the current wear and tear level. For example, if the phone used to hold a charge for 2 days and now only 12 hours, the app will indicate critical wear and tear.
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Once you have AccuBattery installed, calibrate the battery: completely discharge the phone before you turn it off, then charge it to 100% without interruption, which will help the app measure the actual capacity more accurately.
4. Verification through ADB: for advanced users
If you want the most accurate data, you can use Android Debug Bridge (ADB), a technique that requires connecting your phone to your computer and basic command line knowledge, but gives you access to hidden battery settings.
Instructions for checking through ADB:
- Install Platform Tools on your computer.
- Turn on USB debugging on your phone (Settings → Developer).
- Connect Redmi Note 8 to your PC and execute the command in the terminal: adb shell dumpsys battery
- Find the output line capacity, voltage and temperature.
Example of team withdrawal:
level: 78
scale: 100
health: 2 (GOOD)
status: 2 (Charging)
voltage: 4123 (mV)
temperature: 305 (32.5°C)
capacity: 3500 (mAh)Decoding of key parameters:
| Parameter | Meaning | Normal for Redmi Note 8 |
|---|---|---|
| health | Battery status | 2 (GOOD), 3 (OVERHEAT), 4 (DEAD) |
| voltage | Voltage in mV | 3700–4400 mV |
| temperature | Temperature in tenths of °C | 250–400 (25–40°C) |
| capacity | Current capacity in mAh | 3200 mAh (acceptable) to 4000 mAh (ideal) |
If the health setting is 4 (DEAD) or 7 (UNKNOWN), it means a critical battery malfunction and you need to replace it. Also note capacity: if the value is below 2500 mAh, the battery has almost exhausted its life.
What if the ADB does not show capacity?
5. Visual Diagnostics: When a Battery Needs to Be Replaced
Sometimes the battery can be assessed without any special tools, physical signs of wear and tear or malfunction:
- 🔋 Battery bloating -- the phone's body is deformed, the screen can move out of the frame. Dangerous! This battery needs to be replaced urgently.
- ⚡ Spontaneous reboots at 20-40 charge level%.
- 🔥 Overheating even with minimal load (for example, during a call).
- ⏳ Fast discharge – the phone loses 50% of its charge in 1-2 hours on standby.
If you notice a bloating battery, don't try to charge it, it can cause a fire. Turn off your phone and go to the service center. For the Redmi Note 8, the original battery has an MB-J10B articulate (4000 mAh), but there are many fakes on the market. When you replace it, choose UL/CE certified batteries.
To verify the authenticity of the new battery, please note:
- 🏷️ Hologram on the package with the logo Xiaomi.
- 🔍 Serial number – must match the number on the battery.
- 📦 Set – the original comes with moisture protection and instructions.
⚠️ Warning: After you change the battery, be sure to calibrate: completely discharge the phone before turning off, then charge to 100% without interruption. Repeat the procedure 2-3 times.
6. Frequent errors in battery inspection and how to avoid them
Many users make mistakes that distort the results of their diagnosis, and the most common ones are:
Error 1: Checking immediately after the MIUI update
- Once the new firmware is installed, the system may misrepresent its charge level for 1-2 days.
Mistake 2: Using Cheap Chargers
- Unoriginal charges with unstable voltage can damage the battery controller and distort the diagnostic data.
Mistake 3: Ignoring the temperature
- If you test the battery at temperatures below 10°C or above 40°C, the capacity and voltage will be inaccurate.
Mistake 4: Resetting battery statistics before diagnosis
- Applications like AccuBattery take time to collect data, and resetting statistics zeros out all the data, and diagnostics become useless.
To get the most accurate results, follow these rules:
Use the original charging
Charge your phone to 100% before the test
Let the phone cool to room temperature
Do not run resource-intensive applications during diagnosis
Repeat the test 2-3 times for accuracy-->
7.How to extend the life of the Redmi Note 8 battery: practical tips
Even if your battery is still in good condition, following a few rules will help to significantly increase its lifespan:
Optimization of charging:
- 🔌 Avoid charging to 100% and discharging to 0%. Optimal range: 20–80%.
- ⚡ Do not use fast charging all the time, it speeds up wear. 10W.
- 🌙 Charge your phone at night only if it supports Adaptive Charging (in the case of the phone). MIUI It's called Smart Charging).
Temperature control:
- 🔥 Do not leave your phone in direct sunlight (for example, on a car torpedo).
- ❄️ Do not use your smartphone in the cold below -10°C.
- 🎮 During games, remove the case - it can worsen the heat sink.
MIUI settings to save charge:
- 🔄 Enable Battery Mode in Settings: Settings → Battery. → Battery mode → Balanced.
- 📵 Limit the background activity of applications: Settings → Annexes → Permits → Auto-start.
- 🔍 Turn off permanent Wi-Fi and Bluetooth search: Settings → Connections → Additionally.
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The most effective way to extend battery life is to avoid extreme temperatures and keep your phone off the grid, and even small changes in usage habits can increase battery life by 30 to 50 percent.