Xiaomi Redmi Note 8T with its capacious battery of 4000 mAh for several years remains a popular choice among budget smartphones. But even the most reliable battery over time loses capacity: after 300-500 charging cycles, its wear can reach 20-30%, which affects battery life. If your smartphone began to discharge in half a day, turn off at 20-30% charge or overheat during charging, it’s time to check the status of the battery.
In this article, you will find 6 working methods for diagnosing the Redmi Note 8T battery, from hidden engineering codes to professional applications and visual inspection, we will analyze how to find out the real wear without disassembling the phone, what indicators are considered critical, and what to do if the battery is already dead. All instructions are tested on MIUI 12-14 firmware and are relevant for models with original and replaced batteries.
1. Check the battery through the engineering menu (#4636##)
The fastest way to get data on battery status is to use Android’s hidden engineering menu, which is available without root rights or additional apps, but shows raw data that needs to be interpreted correctly.
How to open the menu:
- Open the Phone app.
- Enter the combination: ##4636## (some firmware may require ##4636#*#*1).
- Select Battery Information (Battery Information).
In this section, pay attention to the following parameters:
- 🔋 Level of charge (level) – current percentage in digital form (may differ from the one displayed in the status bar).
- 🔌 Power source – must be a battery (if the phone is not connected to the charger).
- 🌡️ Temperature – The normal range: 25-40°C. Exceeding 45°C in normal use signals battery degradation or charging controller malfunction.
- ⚡ Voltage - should be in the range of 3.7-4.3 V. Below 3.5 V at 100% charge - a sign of severe wear and tear.
⚠️ Note: If the menu does not open after entering the code, check if the engineering codes in the developer settings are disabled (Settings) → Additionally. → For developers → Disable the engineering menu. On some custom firmwares, this method may not work.
Check the correctness of the code entry (without spaces)
Reboot the phone.
Update your firmware to the latest version of MIUI
Try the alternative code ##284##-->
2. USSD codes for Xiaomi battery diagnostics
Xiaomi is hiding several service USSD-commands that allow you to get advanced information about the battery, and these codes only work on the original firmware. MIUI and may differ depending on the region.
The main commands for the Redmi Note 8T:
| Code. | Appointment | Example of inference |
|---|---|---|
| ##6484## | Battery test (shows voltage, temperature, charging cycles) | Battery health: Good (92%) |
| ##64663## | Information about the battery module (serial number, production date) | MF Date: 2021-05-15 |
| ##284## | Charging controller test (checks charging/discharge current) | Charging: 1800 mA (Normal) |
Once you enter the code ##6484##, you will see the Battery Health line with the percentage of wear and tear.
- 🟢 90-100% — battery in excellent condition.
- 🟡 80-89% — Significant wear and tear, but no replacement is required.
- 🔴 Below 80% - critical wear, replacement is recommended.
Important: Some MIUI 13+ firmware may have these codes blocked. If nothing happens after you enter the code, try using diagnostic apps (see next section).
Once a month
Six months
Only when the problems start.
Never checked.-->
Applications for deep diagnostics (AccuBattery, AIDA64)
If the engineering codes didn't work, or if you want more information, use specialized applications that analyze real capacity, the number of charging cycles, and even predict the remaining battery life.
Top.-3 apps for Redmi Note 8T:
- AccuBattery (free, with premium options) 📊 Shows real capacity (for example, 3200 mAh instead of the declared 4000 mAh). 🔄 Tracks charging cycles and degradation rate. ⚡ Analyzes charging/discharge current (useful for checking cables and adapters).
- AIDA64 (free-for-free) 📝 Gives full information about the battery: Technology (Li-Po), Temperature, Voltage, Condition. 🔧 Shows Serial Number and Production Date (if supported by the controller).
CPU-Z
- 📱 Displays Health Level (Health) and Battery Technology.
- 📉 Builds discharge schedules (useful for detecting voltage "failures).
⚠️ Note: AccuBattery applications require calibration – first 2-3 The charge/discharge cycle may show inaccurate data. For an objective assessment, use the application at least 3 days.
💡
If the AccuBattery is below 2,500 mAh at a declared 4,000 mAh, the battery is worn out by more than 35% and needs to be replaced.
4. Visual inspection of the battery (signs of bloating and damage)
If the software methods have shown critical wear, it is worth examining the battery physically. Redmi Note 8T has a non-removable battery, but some signs can be detected without disassembly:
🔍 Symptoms of battery bloating:
- 📱 The screen or back cover has risen (especially noticeable if you put the phone on a flat surface and sway).
- 🔊 When pressed on the body, a crunch or creaking is heard.
- 🔌 The charging cable does not fit tightly into the connector (portal) USB-C shifted).
- 🔥 The phone is very warm even in simple.
If you decide to take apart the phone for inspection, pay attention to:
- 🔋 Battery shape – the bloated battery will be convex, with “inflated” edges.
- 🟠 Color: A normal battery is uniformly gray or black, yellow, green or white spots indicate electrolyte leakage and require urgent replacement!
- 🔌 Contacts – oxidation or corrosion on battery or motherboard contacts.