Introduction: Why it is important to monitor the battery
The battery is one of the most vulnerable components of the Xiaomi Redmi Note 7, which loses capacity and efficiency over time. Even with careful use in 2-3 years, the battery can begin to run out in a few hours, and the device can spontaneously shut down at 20-30% charge, the reasons for this are diverse, from natural wear and tear to improper charging or overheating.
Checking the battery status allows you to identify problems and take action: replace the battery, adjust your energy settings or change your usage habits. In this article, we will discuss 5 reliable diagnostic methods - from built-in MIUI tools to third-party applications and physical examination, you will learn how to interpret wear indicators, which values are considered critical, and what to do if the battery is already "dying."
Method 1: Checking through the engineering menu (USSD codes)
The fastest way to assess battery status is to use hidden service codes that provide access to technical information, including current battery capacity, number of charging cycles and temperature. Two basic codes are suitable for the Redmi Note 7:
- 🔢 ##4636## - opens a menu with data on battery, network usage and work statistics;
- 📊 ##2846579## → ProjectMenu → Battery Info – more detailed information (does not work on all firmware).
After entering the first code, go to the Battery information tab.
- 🔋 Level - current percentage of charge;
- 🌡️ Temperature - Temperature in degrees (normal: 25-40°C with active use);
- 🔄 Voltage - voltage (Redmi Note 7: 3.7-4.4 V).
If the voltage is below 3.5 V at 100% charge or the temperature exceeds 45 ° C in idle - these are signs of severe wear or malfunction of the controller. Also note the Health parameter (if it is displayed): the Good value means that the battery is normal, Replace soon - requires replacement.
⚠️ Note: Do not enter random codes on the Redmi Note 7 - some of them can reset settings or run hardware tests.
Method 2: Diagnostics through the Security Application (MIUI)
Xiaomi has built a battery monitoring tool into MIUI, which is available without installing third-party software, to take advantage of:
- Open the Security app (the shield icon).
- Go to the Optimization section → Battery.
- Click on the three dots in the top right corner and select Battery Status.
This will show you a percentage of battery wear, so if you see 85 percent, for example, it means that the battery capacity has decreased by 15 percent from the factory capacity (from 4,000 mAh to ~3400 mAh), and the critical wear is more than 30 percent, which means that the battery may not hold a charge even half a day.
In the same section, you can find statistics on the consumption of charges by apps. If you notice that an application consumes more than 10% per hour in the background (for example, Facebook or TikTok), you should limit its activity through the settings AutoRun and Background activity.
| Battery wear (%) | Status. | Recommendations |
|---|---|---|
| 0–10% | Excellent. | The battery is almost new. You just need to keep a temperature check and avoid full discharges. |
| 10–20% | Good. | The capacity has decreased slightly, but the charge is stable, and you can optimize the background. |
| 20–30% | Satisfactory | The charge is worse, especially when used actively, and it's worth considering replacing in the near future. |
| 30% or more | Critical | The battery is quickly discharged, sudden shutdowns are possible, and replacement is recommended within 1-3 months. |
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If there is no wear schedule in the Battery Status section, update the Security app via Google Play or clear its cache in your phone's settings.
Method 3: Use of third-party applications (AccuBattery, CPU-Z)
The built-in MIUI tools don't always show the full picture, and you can use third-party tools to make your diagnosis more accurate.
- 📱 AccuBattery analyzes charging cycles, temperature and real capacity, shows battery health as a percentage and predicts the remaining lifespan;
- 🖥️ CPU-Z — displays technical data including voltage, battery manufacturing technology and number of charging cycles.
To check the battery through AccuBattery:
- Install the app from Google Play.
- Charge your phone to 100% and wait for the app to collect data (usually 2-3 charge/discharge cycles are required).
- Go to the Health tab - here will be the percentage of wear and real capacity in mAh.
In CPU-Z, the information you need is in the Battery tab.
- 🔋 Capacity – current capacity (compare with factory 4000 mAh for Redmi Note 7);
- 🔄 Cycle count – number of full charging cycles (norm: up to 500 cycles).
⚠️ Attention: Some applications (e.g, 3C Battery Monitor requires root rights to obtain complete data, and on non-rooted devices, they can show inaccurate values.
☑️ Preparation for battery test
Method 4: Visual inspection and physical signs of wear and tear
Sometimes battery problems can be detected without software, by external signs.
- 🔥 Battery bloating – the phone body is deformed, the screen “steps away” from the frame, or the smartphone does not lie flat on the table;
- ⚡ Fast discharge – the charge drops from 100% to 0% in 2-3 hours without active use;
- 🔌 Charging problems – the phone does not recognize the charger, charges in jerks or only at a certain position of the cable;
- 💥 Spontaneous reboots – the device turns off at 20-40% charge and only turns on after connecting to the network.
If you notice a bloating battery, stop using your phone immediately, which is dangerous to your health! A bloated battery can damage your screen, your motherboard, or even ignite, and require an urgent replacement at the service center.
Other physical signs:
- 🌡️ The phone heats up even when light load (for example, when watching video);
- 📉 Charge "sinks" - for example, from 50% immediately drops to 10%;
- 🔊 Extraneous sounds (crackling) when pressing the body.
To check for battery bloating, you can use a simple test: put your phone down on a flat surface and slightly press the center of the back cover. If the case is "playing" or bending, this is a sign of bloating.
What to do if the battery is blown?
Method 5: Discharge test (battery calibration)
If the phone shows an inadequate charge level (e.g., it turns off at 30 percent), it may require calibration of the battery controller, which also helps to assess the actual capacity.
- Charge the Redmi Note 7 to 100% and keep charging for another 1-2 hours (for stabilization).
- Turn off the charger and use the phone as normal until it is discharged to 0% and turned off.
- Don’t turn the phone on right away! Wait 5-6 hours (this is important for a controller data reset).
- Charge your phone to 100% without interruption.
After this procedure, the battery controller will update the actual capacity data, and the percentage of charge will be displayed more accurately, and if after calibration the phone still turns off at 20-30%, this confirms the strong wear of the battery.
For a more accurate test, you can use AccuBattery in discharge monitoring mode, run it before you start the test, and it will record a graph of the voltage drop and help you detect tank drawdowns.
⚠️ Warning: Do not run a discharge test if the battery is swollen or the phone is overheating.
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Calibration of the battery helps only when the controller fails, but does not restore the physically worn-out battery.
What to do if the battery is worn out?
If the diagnosis showed wear and tear of more than 30% or revealed physical defects, there are three options:
- The original battery for the Redmi Note 7 costs about 1000-1500 rubles, replacement in the service will cost 500-1000 rubles additionally. Use only original or certified batteries (for example, from Xiaomi or ZMI).
- Optimizing energy consumption – if replacement is not yet possible, reduce the load: 📵 Turn it off. 4G/LTE, If you don't use the Internet; 🌙 Turn on a dark theme and reduce the brightness of the screen; ❄️ Limit the background activity of applications in the Battery settings.
Use of an external battery
Quick Charge 3.0
Xiaomi Mi Power Bank 3
If you are replacing the battery yourself, consider:
- 🛠️ You'll need tools: plastic spatula, screwdriver. T3/T4, glue-dryer;
- 📄 Before disassembling, check out the guides on YouTube or 4PDA — Redmi Note 7 design has fragile plumes;
- ♻️ Recycle old battery correctly – don’t throw it away in regular trash!
After the battery is replaced, it is recommended to calibrate (described in Method 5) and install a monitoring application (e.g., AccuBattery) to monitor the status of the new battery.