Xiaomi Redmi Note 7 — one of the most popular smartphones 2019 Even with a large battery for a year. 4000 mAh eventually loses capacity. If the phone runs out in a few hours, it turns off when it's not. 20-30% When you're charging or overheating while charging, it's time to diagnose the battery. In this article, you'll find all the working ways to check the Redmi Note battery. 7, including hidden engineering menus, USSD-codes and third-party utilities.
We tested each method on a real device (MIUI 12.5, Android 10) and pointed out which data to consider and which to ignore. For example, the battery status score in standard MIUI settings is often overstated and does not reflect real wear and tear, and you will learn how to distinguish a software failure from physical battery wear and when to change it.
1. Verification through standard MIUI settings
The easiest, but least accurate, way to do this is to use the built-in MIUI tools, which will show you basic information, but they won't reveal the full wear pattern.
Open Settings → Battery and Performance → Battery status. Here you will see:
- 🔋 Wear level – percentage of capacity loss (but often understated).
- ⚡ Charging cycles – how many times the battery has been 100% charged (normal up to 500 cycles).
- 🌡️ Temperature - optimal 25-35°C, above. 40°C dangerously.
If this menu says, "Battery status: good," but the phone runs out in 3-4 hours, the data is inaccurate. In 70% of cases, MIUI hides real wear and tear so as not to scare users. For accurate diagnosis, move on to the following methods.
2. Engineering menu: hidden battery data
The engineering menu (#4636##) gives you access to battery specifications that MIUI doesn't show, which works on all Redmi Note 7s regardless of the firmware version.
Instructions:
- Open the Phone app.
- Enter the combination ##4636## (without call confirmation).
- Select the Battery Information item.
Pay attention to the following parameters:
| Parameter | Normal value. | What does deviation mean? |
|---|---|---|
| Charge level (Level) | Corresponds to the percentages on the screen | If it is very different, calibration failure |
| Voltage (Voltage) | 3.7-4.2 V at 100% charge | Below 3.5 V - deep discharge, above 4.3 V - recharge |
| Temperature (Temperature) | 25–35°C | Above 40°C – overheating, below 10°C – risk of damage |
| Technology (Technology) | Li-ion or Li-poly | If the other type is a fake battery |
The critical parameter is Voltage. If it's below 4.0 V at 100% charge, the battery is worn out, and also check how quickly the voltage drops when used: if it drops from 4.1 V to 3.8 V in 10 minutes of play, the capacity is lost by at least 30%.
Enter code ##4636##| Compare Level and percentages on screen |Write Voltage at 100% charge |Control Temperature in simple and under load-->
3. USSD-battery-diagnostic
In addition to the engineering menu, the Redmi Note 7 also has special service codes for battery testing, which provide more detailed information than standard settings.
Basic codes:
- 📱 ##6484## - Battery test (shows real capacity in mAh).
- 🔍 ##64663## - Checking hardware components, including battery.
- ⚡ ##36446337## - Information about the latest charging cycles.
Once you enter the code ##6484##, you will see the MBAT Test menu, and there are two things that matter:
- Battery Capacity is the current capacity in mAh. Compare with passport 4000 mAh. If the difference is greater than 20%, the battery is worn out.
- Battery Health is 0 to 100 percent. Below 80 percent, it's time to think about replacing.
If the codes don't work, the manufacturer has blocked them in your firmware version, in which case use third-party apps (see next section).
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Before entering USSD-disable the codes SIM-card (if the phone asks for confirmation of call) This will prevent accidental call to the operator.
4. Applications for deep diagnostics
Third-party utilities show data that is hidden in MIUI. We tested 5 popular apps and selected the two most accurate ones for the Redmi Note 7.
1. AccuBattery (Play Market)
- 📊 Shows the actual battery capacity (not passport capacity).
- 🔄 Tracks charging cycles and wear.
- ⚡ Analyzes the charging/discharge speed.
How to use:
- Install and launch the application.
- Charge your phone to 100% and wait for the notification “Charge is complete”.
- In the Health section, look at the Estimated Capacity.
2. CPU-Z (Play Market)
- 🔋 Shows voltage, temperature and battery technology.
- 📱 Provides information about the processor and memory (useful for complex diagnostics).
The Battery tab in CPU-Z displays the same data as the engineering menu, but in a more convenient way. Pay attention to Health — if Unknown status means MIUI blocks access to this information.
Some apps (like Battery HD) show inaccurate data for Xiaomi.We recommend using AccuBattery and CPU-Z only, as they read information directly from the battery controller.
Why does MIUI hide the real wear of the battery?
Physical inspection of the battery
If the software methods show critical wear and tear, but you doubt the results, look at the battery visually.
Signs of a faulty battery:
- 🔥 Bloating: If the battery case swells (even slightly), it needs to be replaced immediately!
- 💧 Electrolyte dashing - white or green plaque on a board near the battery.
- 🔌 Contact oxidation - green plaque on metal connectors.
- 🧲 Detachment of the label - says about overheating.
How to Disassemble Redmi Note 7:
- Turn off the phone and remove it. SIM-map.
- Heat the back cover with a hair dryer (60-70°C) to soften the glue.
- Tap the cover with a plastic spatula (start at the corner near the charging connector).
- Disconnect the battery plume (it is glued to the motherboard).
⚠️ Warning: If the battery is swelling, don't try to puncture or bend it, it can cause fire. Carefully remove it and dispose of it at a special reception center. It's dangerous to keep a bloated battery at home!
If you are not sure about your skills, it is better to contact the service.The cost of replacing the battery in the Redmi Note 7 is from 1500 to 2500 rubles (depending on the quality of the battery and the region).
6. Battery calibration: when and how to do
Sometimes the problem is not wear and tear, but the battery controller fails, so for example, the phone shows 30 percent charge, but suddenly turns off, and calibration will help.
When calibration is needed:
- 📉 The phone turns off when 15-30% charge.
- 🔄 Charge percentages jump (e.g., 50% to 20% per second).
- ⚡ The charge is jerky (fast, then slow).
Step-by-step:
- Discharge the phone before automatically shutting down.
- Turn it on and wait for the switch off again (repeat 2-3 times).
- Connect to charging and do not turn on until the green indicator lights up (100%).
- Turn off the charging, turn on the phone and wait for the full load.
- Repeat the charging-discharge cycle again.
⚠️ Attention: Calibration only helps with software failures. If the battery is physically worn out (blown, loss of capacity), calibration will not restore its properties. Also, do not calibrate the phone more than 1 time in 3 months - this reduces the battery life.
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Calibration of the battery is not a "treatment," but a reboot of the controller's data, and it doesn't restore capacity, it only corrects the error in the charge display.
7 When is the time to change the battery
Even if the battery is visually intact, it should be replaced at the following signs:
| Symptoms. | Reason. | Decision |
|---|---|---|
| The phone discharges in 2-3 hours without loading | Capacity dropped below 60% of face value | Battery replacement |
| Charging is only in the off state | Controller or contacts damaged | Diagnostics in the service |
| The phone heats up when charging above 45°C | Short circuit in the battery | Immediate replacement! |
| Charge percentages jump (e.g. 80% → 40% → 80%) | Controller failure or cell wear | Calibration or substitution |
| The phone does not turn on without charging, even if it shows 20-30%. | Deep discharge or loss of capacity | Replacement + calibration of the new battery |
The average battery life of a Redmi Note 7 is 2-3 years (or 500-600 charge cycles). If the phone is older, the probability of battery wear is 80%. Also pay attention to the quality of the charger: cheap power supplies accelerate battery degradation by 2-3 times.
Advice on choosing a new battery:
- 🔋 Buy only original batteries (articles) MB-J21 For the Redmi Note 7).
- 🛡️ Check for a protection controller (it prevents overcharging).
- 📦 Avoid batteries without packaging or with damaged labels.