How to accurately check the battery capacity on Xiaomi: from secret codes to multimeter

The battery is one of the most vulnerable components of Xiaomi’s smartphone, and its capacity inevitably declines over time. If your Redmi or POCO started to run out in a few hours and the battery indicator shows inadequate values, it’s time to check the actual capacity of the battery. But how do you do this without special equipment and without damaging the device?

In this article, you will find 5 proven ways, from simple (using hidden menus and apps) to professional (using a multimeter), we will also analyze what values are considered normal for different Xiaomi models, and what to do if the capacity is critically low. Importantly, methods using the engineering menu (#4636###) work only on smartphones with Qualcomm processors - on devices with MediaTek, alternative approaches will be required.

Before you start checking, note that some methods require unlocking the bootloader or root rights, which may deprive you of warranty. If your Xiaomi is still on warranty, it is better to contact the service center - there the battery capacity will be checked using specialized equipment (for example, the Cadex C7400 tester).

1. Testing capacity through the engineering menu (#4636##)

The fastest way to know battery status is to use the hidden engineering menu available on most Xiaomi smartphones with a Qualcomm processor.This method does not require installing third-party applications and works even without root rights.

To open the menu:

1. Open the Phone app.
2. Enter the combination ##4636##.
3. In the window that appears, select Battery Information.

Here you will see a few key parameters:

• 🔋 Level of charge (level) - current percentage of charge.
• 🔌 Voltage – should be in the range of 3.7-4.2 V when fully charged.
• 📊 Temperature - the norm is 20-45°C.
• ⚡ Charging technology (for example, Fast charge or charging) USB.

However, the actual battery capacity in mAh is not on this menu, only the relative state is displayed here. Additional steps are required to get accurate data (see next section).

⚠️ Note: Some Xiaomi models (e.g. Redmi Note 10 Pro) POCO X3 Pro) the engineering menu may be blocked by the manufacturer, in which case nothing will happen when you enter the code.

2.Use of applications for battery diagnostics

If the engineering menu is not available or does not provide enough information, third-party applications will come to the rescue, which allows you to get more detailed data on the state of the battery, including the actual capacity per mAh and the number of charging cycles.

The best apps for Xiaomi:

• 📱 AccuBattery – shows battery wear, discharging speed and approximate operating time, suitable for all models, but requires calibration (multiple full charge/discharge cycles).
• 🔧 CPU-Z — Battery displays voltage, temperature and design capacity (not always accurate).
• 🛠️ AIDA64 — It's a professional tool that shows Design capacity and Current capacity, and it works without root, but it may require calibration to be accurate.
• 📊 Battery Guru monitors battery health in real time and predicts remaining lifespan.

Example of data from AIDA64 for Xiaomi Redmi Note 9 Pro:

If the difference between Design capacity and Current capacity is more than 20%, it is time to replace the battery, for example, for the POCO F3 with a factory capacity of 4520 mAh, the critical value is less than 3600 mAh.

⚠️ Note: Apps like AccuBattery can show low capacity in the first days of use. Wait at least 3-5 full charging cycles for accuracy.

Charge your smartphone to 100%|Install one of the recommended applications|Reset the device|Calibrate (discharge to 0% and charge again)-->

3. Checking through ADB (for advanced users)

If you want the most accurate data, you can use Android Debug Bridge (ADB), which requires connecting your smartphone to your computer, but gives you access to hidden parameters, including the actual battery capacity.

Instructions:

1. Enable Developer Mode on Xiaomi: Go to Settings → About Phone. Tap 7 times on MIUI Version. Go back to Settings → Additional → For Developers. Activate Debugging on USB.

ADB Tools

adb shell


dumpsys battery

In the commands output, look for the lines:

• charge counter: XXXX is the current charge in microcoulombs (divided by 3600 to get mAh).
• Capacity: YY is the percentage of charge reported by the system.
• Voltage: ZZ is the voltage in millivolts.

For example, if the charge counter: 18000000, That's the real capacity for 100% charge: 18000000 / 3600 ≈ 5000 mAhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh.

This method is more accurate than applications, but requires command line skills. If you've never used ADB, you better choose another method.

💡

To make this calculation easier, use online calculators to translate microcoulombs into mAh, such as this tool.

Physical check by multimeter (for experienced)

If you're ready to disassemble a smartphone, the multimeter will give you the most accurate results, a method that is suitable for diagnosing removable batteries (for example, in older Redmi 4X or Redmi Note 5 models) or if you have already removed the back cover.

What you need:

• 🔧 Multimeter with voltage measurement mode (DC).
• 🔋 Battery (removable or removed from the device).
• 🔌 Load (e.g. 3.7V light bulb or 10 Ohm resistor).

Step-by-step:

1. Measure the idling voltage (no load). For Li-ion batteries, it should be in the range of 3.7-4.2 V.
2. Connect the load and detect the time it takes for the voltage to drop to 3.0 V (critical minimum).
3. Calculate the capacity by the formula: Capacity (mAh) = (Low current in mA) × (Discharge time in hours).

Example: if the light bulb consumes 200 mA and the battery is discharged in 10 hours, the capacity is 200 mA × 10 h = 2000 mAh.

⚠️ Warning: Do not discharge the battery below 2.5V - this can lead to irreversible loss of capacity!

5. Capacity assessment by operating time

If you don't want to take your smartphone apart or install apps, you can estimate the capacity by battery life.

• 📱 Fully charged smartphone.
• 📊 Fixed load (e.g., watching YouTube videos at 50% brightness).
• ⏱️ Stopwatcher.

Algorithm:

1. Charge Xiaomi to 100% and disconnect from the network.
2. Run your video in Full HD at maximum brightness (or use the PCMark Autonomousity Test).
3. Take a look at the time the battery will run to 0%.
4. Compare the result with the passport data (see the table below).

If the battery life is less than critical, the battery capacity is likely to fall below 70% of the factory capacity. For example, for Xiaomi 13 discharge in 6 hours when watching a video indicates severe wear.

💡

This method only gives a rough estimate, since the run time depends on MIUI optimization, application background activity and ambient temperature.

6. When is it time to change the battery?

Even if the battery capacity has decreased, it doesn't always mean it needs to be changed urgently, but here are some specific signs that the battery needs to be replaced:

• 🔋 Smartphone discharges in 3-4 hours with normal use (social networks, instant messengers).
• ⚡ Charging occurs unevenly (for example, from 80% to 100% goes a very long time).
• 🔥 Xiaomi case heats up in the battery area even without load.
• 📉 In applications like AccuBattery, battery health (Health) is below 60%.
• 🚨 Smartphone spontaneously turns off at 20-30% charge.

If you have 2-3 items on your list, you should consider replacing the battery. Xiaomi's average battery life is 2-3 years (or 500 charging cycles), and then the capacity drops to 60-70%, and the autonomy decreases markedly.

The cost of replacing the battery in the service center:

• Redmi Note / POCO: 1500–2500 ₽ (model-wise).
• Xiaomi 12/13: 3000–4500 ₽ (due to the complexity of disassembly).
• Self-sustained replacement: 800-1500 ₽ (battery price for AliExpress).

⚠️ Note: When replacing batteries, use only original or certified batteries (e.g., labeled batteries). ATL or SDI). Cheap analogues can swell or ignite!

FAQ: Frequent questions about checking battery on Xiaomi