Owners of the Xiaomi Redmi Note 8 Pro often face the problem of fast battery discharge, even if the smartphone is not used intensively. The reason may be incorrect calibration of the power controller, a system that tracks the real level of battery charge. Over time, the data on the capacity “dies” with the actual state, and the phone starts to turn off at 20-30% charge or, conversely, show 100% when the battery is only half charged.
Calibration of the battery is not a myth or a magic pill, but a technical procedure that helps to reset the controller errors and return adequate readings of the charge level. However, it is important to understand that if the battery is physically worn out (for example, its capacity has fallen below 70% of the factory), calibration will not restore the former autonomy. In this case, you will need to replace the battery. In this article, we will discuss how to distinguish software failure from hardware wear and calibrate correctly without damaging the smartphone.
Why the battery calibration on the Redmi Note 8 Pro is lost
The power controller in the Redmi Note 8 Pro (as in other Xiaomi smartphones) works on algorithms that take into account the voltage, current and temperature of the battery.
- 🔋 Frequent charging interruptions – if you constantly plug/disable the charger without waiting for the full cycle (0–100%), the controller loses its “reference points".
- 📉 Deep discharge – if the battery was discharged before the automatic shutdown (below 3.2V), it could damage the cells and knock the calibration.
- 🔄 Updates MIUI — sometimes the firmware resets the power consumption settings, which leads to incorrect readings.
- 🌡️ Overheating or supercooling – extreme temperatures accelerate the degradation of lithium polymer batteries and can distort controller data.
Another common reason is the use of non-original chargers: Cheap power adapters can deliver unstable voltages, which leads to errors in the calculation of capacity. If you notice that the battery discharges in “jumps” (for example, from 40% to 1% in a few minutes), it is likely that calibration, not physical wear, is to blame.
How to check the battery status before calibration
Before you start calibrating, make sure that the problem is really the failure of the controller, not the wear of the battery.
- Open the Settings app → Battery and performance → Battery condition.
- If you look at the wear graph, if the capacity is below 80 percent, calibration won't help, you need a replacement.
- Use the engineering menu (code ##4636##) to check the voltage and temperature.
You can also use third-party utilities like AccuBattery (available on Google Play) that show the actual battery capacity, the number of charging cycles and the discharge rate. If the app detects sharp jumps in charge level (for example, from 50% to 20% in 5 minutes), this is a clear sign of the need for calibration.
| Parameter | Normal value. | Sign of a problem |
|---|---|---|
| Battery capacity | 90-100% of the factory | Below 80% |
| Voltage (at 100% charge) | 4.35–4.4 V | Above 4.5 V or below 4.2 V |
| Temperature in plain | 25–35°C | Above 40°C or below 10°C |
| Discharge speed (in plain) | 0.5-1% per hour | More than 2% per hour |
⚠️ Warning: If the battery temperature exceeds 45°C when charging or using, immediately stop calibration. overheating can cause the battery to bloat!
Calibration Preparation: What to Do in Advance
Calibration of the battery is a multi-hour process that requires a full cycle of discharge and charge.
- 🕒 Allocate time – the procedure will take 8-12 hours (depending on the capacity of the battery).
- 🔌 Use original RAM – non-original adapters can give unstable voltage.
- 📵 Turn off background processes – close all apps, turn off mobile data and Wi-Fi.
- 🔋 Charge your smartphone to 100% – before calibration, the battery must be fully charged.
It is also recommended to back up your data. Although calibration does not delete files, in rare cases, a controller reset can lead to an unexpected reboot. For reliability, copy important photos and contacts to your computer or to the cloud.
Charge your phone to 100% |Disable mobile Internet and Wi-Fi |Close all background applications |Prepare the original charger |Prepare a backup of the data-->
Step-by-step: how to calibrate the battery on the Redmi Note 8 Pro
There are two ways to calibrate: software (via the smartphone menu) and hardware (using engineering codes), and we recommend starting with the first method, which is safer and requires no special knowledge.
Method 1: Calibration through settings (without root)
- Charge your phone to 100% and leave it on charge for another 1-2 hours (to calm down the controller).
- Turn off the charger and use the smartphone as normal until it is discharged before automatically shutting down.
- Don't turn on your phone right away! Wait 5-6 hours (this is important for relieving residual voltage).
- Connect the original RAM and charge the phone to 100% without interruptions.
- After full charging, reset your battery settings: go to Settings → About Phone → Reset settings → Reset battery settings.
Method 2: Calibration through the engineering menu (for experienced)
It's a deeper way, but it requires caution, and doing the wrong thing can cause the system to fail.
- Open the Phone app and enter the code ##4636##.
- Go to the Battery Information tab and look at the Charge Level parameter.
- Connect the charger and wait until the level shows 100%, and the status does not change when the Charge is completed.
- Turn off the power and enter the battery reset command (if available) in the engineering menu.
- Discharge the phone before turning off, then charge to 100% without interruptions.
⚠️ Warning: If after calibration, the phone starts to show a charge of less than 100% when the charger is connected, do not panic. This is normal - the controller "learns" again. Wait for 2-3 charging cycles, and the readings stabilize.
💡
If after calibration, autonomy has not improved, check the battery consumption in Settings → Battery. It may be the fault of an incorrectly working application (for example, messenger or social network) that discharges the phone in the background.
What to do if calibration does not help
If the problem persists after the procedure, the following reasons are possible:
- 🔋 Physical wear of the battery -- if the capacity is below 70 percent, the calibration is powerless.
- 🔄 Firmware failure - sometimes mistakes MIUI It's not a good way to get the controller working properly.
- 📱 Motherboard problems – if the phone suddenly shuts down at 50% charge, it could be a sign of a power controller malfunction.
To diagnose hardware problems, perform the test:
- Turn off the phone.
- Connect it to the charger.
- If the charge indicator does not appear on the screen, this may indicate a faulty connector or controller.
If you suspect battery wear, check it visually: the battery should not be bloated or deformed. A bloated battery is dangerous - it should be replaced immediately!
How do you check for battery bloating?
How to extend battery life after calibration
To keep the calibration results longer, follow these rules:
- 🔌 Avoid full discharge – recharge your phone at 10-20% charge.
- ☀️ Don’t overheat your smartphone – don’t leave it in the sun or near heat sources.
- 📵 Disable unnecessary functions — GPS, Bluetooth and mobile data in the background severely drain the battery.
- 🔄 Update the firmware - in new versions MIUI often optimize energy consumption.
It is also useful to calibrate the battery every 3-6 months, even if there are no obvious problems, which will help maintain the accuracy of the controller readings. If you use the Redmi Note 8 Pro intensively (games, video shooting), calibration can be done more often.