Xiaomi Redmi Note 7 is still one of the most popular budget smartphones, but its battery capacity of 4000 mAh after 3-4 years of operation often begins to “catch”: the fall in autonomy, sudden shutdowns at 20-30% charge, slow charging are all signs of battery wear.
In this article, we’ll look at all the available ways to diagnose a Redmi Note 7 battery, including hidden engineering menus, USSD codes, third-party apps, and even hardware tests. You’ll learn how to interpret wear metrics when it’s time to change the battery, and what to do if the smartphone “lies” about the percentage of charge, and at the end, answers to frequent questions and life hacks to extend the battery life.
1. Check through the engineering menu (no root)
The most reliable way to know the real capacity of the battery is to go to the hidden engineering menu of Xiaomi, which is available on all smartphones of the brand, including the Redmi Note 7, and does not require superuser rights. Importantly, the data in this menu is updated in real time, so it is better to check with a battery charge of 20% to 80%.
Instructions:
- 📱 Open the phone app and enter the combination: ##4636##
- 🔧 In the menu that appears, select Battery Information (or Battery Information).
- 📊 Pay attention to the lines: Level - current charge in percentage; Voltage - voltage (normal: 3.7-4.2 V); Temperature - temperature (optimally: 25-40°C); Health - condition, if any).
Unfortunately, some MIUI firmware may not have a Health item, so note Voltage: if it's above 4.3V at 100% charge, it's a sign of a controller malfunction or battery wear.
Voltage at 100% charge (not higher than 4.25 V)|Temperature (not higher than 45 ° C)|Charge level (must coincide with the indicator)|No error in status
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2. USSD-battery-diagnostic
If the engineering menu is not available or does not show the necessary data, you can use the service menu. USSD-They work on all Redmi Note 7s regardless of the version. MIUI. The main advantage of this method is speed: the result appears immediately after entering the combination.
List of working codes for Redmi Note 7:
- 🔋 ##4636## - basic information about the battery (analogue of the engineering menu);
- 📊 ##2840## - Battery test (shows voltage and temperature);
- 🔍 ##6484## - Hardware check (includes battery test).
Once you enter the code ##2840##, you will see a screen with a voltage graph.
- 🟢 At 100% charge: 4.1-4.2 V;
- 🟡 At 50%: 3.8–3.9 B;
- 🔴 At 10%: 3.4–3.5 B.
If the voltage is very abnormal (for example, 3.6 V at 50% charge), this indicates severe wear or malfunction of the power controller.
Once a month |Only when problems start |Never checked |I check before selling my phone
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3 Third-party applications: AccuBattery, CPU-Z and others
If standard methods don’t give you the full picture, specialized applications come to the rescue: they analyze charging cycles, measure real capacity, and even predict the remaining battery life. Importantly, for accurate data, an application may need several charging-discharge cycles (usually 2-3 days of use).
Top.-3 apps for Redmi Note 7:
| Annex | Functions | Needs root? | Reference |
|---|---|---|---|
| AccuBattery | Shows real capacity, wear, temperature, charging speed | ❌ No. | Google Play |
| CPU-Z | Displays voltage, temperature, battery technology (Li-Po) | ❌ No. | Google Play |
| Battery Guru | Monitoring of charging cycles, depreciation forecast, overheating notifications | ❌ No. | Google Play |
How to use AccuBattery (the most accurate application):
- Install and open the application.
- Connect the charger and wait for 100% charge (the application will record data).
- Use your phone as normal until it is 10-15% discharged.
- In the Health section, an estimate of wear in percentage will appear.
⚠️ Attention: If the app shows wear of more than 40%, the battery is recommended to be replaced. With wear of 20-30%, the autonomy is significantly reduced, but the battery is still usable.
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4. Check through ADB (for advanced users)
If you're willing to use a developer tool, the ADB method will provide the most accurate data, which is suitable for those who know how to work with the command line and are ready to connect the phone to a PC. Advantage: ADB reads data directly from the power controller, without intermediaries in the form of applications.
Step-by-step:
- Download and install Platform Tools (includes ADB).
- On your phone, turn on USB Debugging: Go to Settings → About Phone; 7 times click on the MIUI Version to activate Developer Mode; Return to Settings → Additional → For Developers; Activate Debugging over USB.
adb shell dumpsys batterylevel: 85
voltage: 4023 (mV)
temperature: 320 (×0.1°C = 32°C)
health: 2 (GOOD)Decoding the health parameter:
- 2 (GOOD) - the battery is normal;
- 3 (OVERHEAT) - overheating;
- 4 (DEAD) - the battery is defective;
- 7 (UNKNOWN) - no data available.
⚠️ Note: If health shows 4 (DEAD), But the phone turns on, and the problem may be the charging controller, not the battery itself, and that requires a diagnosis at the service center.
5.Visual signs of battery wear
Even without special tools, you can suspect problems with the battery for indirect reasons. If you notice at least 2-3 symptoms from the list below, it is time to diagnose one of the methods described above.
Alert signals:
- 🔌 The phone does not turn on when connecting the charging until it is on a charge for 10-15 minutes;
- 📉 Charge drops from 30% to 0% in a few minutes;
- 🔥 The body heats up in the battery area even without loading;
- 🛑 Redmi Note 7 shuts down at 15-20% charge;
- ⚡ Charging is too slow (for example, 1% in 10 minutes).
A bloated battery is especially dangerous. If the phone body becomes convex and the back cover is moving away, turn off the phone immediately and do not use it until the battery is replaced! Lithium polymer batteries can ignite if damaged.
What to do if the battery is blown?
6.When it's time to change the battery: table of wear
To see how critical your battery wear is, use the table below, which is based on data from lithium polymer battery manufacturers and tests from Xiaomi Redmi Note 7.
| Battery wear and tear | The remaining container | Signs. | Recommendations |
|---|---|---|---|
| 0–15% | 85–100% | Autonomy is almost like a new phone | Keep using, keep an eye on the temperatures. |
| 16–30% | 70–84% | The charge is kept 20-30% less than before | Limit the charge to 80%, avoid overheating |
| 31–50% | 50–69% | The phone is discharged in 4-6 hours, turns off at 15-20% | Prepare to be replaced, avoid deep discharges |
| 51% and above | Less than 50% | Autonomy 2-3 hours, the phone may not turn on | Urgent replacement! Risk of bloating and damage to the board |
⚠️ If the wear and tear exceed 50%, but you continue to use the phone, it can lead to the use of the phone:
- Damage to the power controller (repair will cost 3-5 thousand rubles);
- Bloating of the battery and deformation of the body;
- Data loss due to sudden shutdowns.
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