How to check the remaining battery capacity on Android: from hidden codes to ADB

A smartphone runs out of charge in half a day, although it used to hold a charge for a day? Perhaps a worn-out battery is to blame. Manufacturers often hide the real state of the battery, but there are ways to get accurate data. In this article - 7 proven methods, from simple (through phone settings) to advanced (commands ADB and engineering menu).

You will learn how to interpret indicators capacity, charging cycles and battery health status (SOH), as well as what to do if the values are critically low. All instructions are adapted to modern versions. Android 12–15 and work on devices from Samsung, Xiaomi, Google Pixel and other brands. Important: some methods require rights root or an unlocked bootloader - this will void the warranty.

1. Built-in Android tools: where the battery information is hidden

Starting with Android 9 Pie, hidden menus with battery information have been added to the system. They do not need to be installed - you just need to know the correct paths.

On most devices, go to: Settings → Device care → Battery status (for Samsung)

or

Settings → Battery → Three dots (menu) → Battery status (for Xiaomi/Redmi/POCO).

• 🔋 Capacity —current maximum charge in mAh (compare with the passport value).
• 📊 Charging cycles —how many times the battery has been charged to 100%. After 500 cycles, the capacity usually drops by 20–30%.
• ⚡ Voltage —real-time voltage (norm: 3.7–4.4 V for Li-ion).

If these items are not available, try entering in the application Phone code: ##4636## → select Battery information. This displays charge level, temperature and technology (Li-ion/Li-Po).

⚠️ Attention: On some devices (for example, OnePlus or Oppo) engineering menu codes may reset network settings Before entering, save APN access points.

2 Diagnostic applications: AccuBattery, CPU-Z and alternatives

Third-party utilities provide more detailed information than standard tools. The best of them:

• 📱 AccuBattery (free, with premium options) - shows real capacity, wear and discharge rate works without root, but accurate data requires calibration (2-3 full charging cycles).
• 🔍 CPU-Z (tab Battery) - displays temperature, voltage and battery technology. Suitable for comparison with passport data.
• 🛠️ Battery Guru - monitors charging cycles and warns of overheating. Useful for devices with removable batteries.

How to use AccuBattery:

1. Install the application and charge the phone to 100%.
2. In the section Health look at the parameter Calculated capacity is the current maximum of your battery.
3. Compare with the rated capacity (for example, 5000 mAh u Samsung Galaxy M53). A difference of more than 20% is a reason for replacement.

Close all applications

Turn off Wi-Fi and mobile data

Charge the phone to 100%

Use the original cable-->

Example report from AccuBattery for Xiaomi Redmi Note 11:

Parameter	Value	Normal
Calculated capacity	4100 mAh	5000 mAh (passport)
Wear	18%	Up to 10% - excellent, 10–20% - satisfactory
Temperature	32°C	20–40°C (critical above 45°C)
Charging cycles	312	Up to 500 is normal, after - degradation

⚠️ Attention: Applications without root show calculated data, not direct readings from the battery controller. For accuracy, use the methods in the following sections.

3. Engineering menu (Engineer Mode): hidden data without root

The Engineering menu is a service section where manufacturers make low-level settings. It can be accessed through secret codes, but be careful: incorrect actions can disrupt the operation of the phone.

Entry methods:

• 📞 For Mediatek (most Xiaomi/Redmi/Realme): enter ##36446337## → Battery Information.
• 🤖 For Qualcomm (Samsung, OnePlus, Google Pixel): ##4636## → Battery information.
• 🍎 For Exynos (Samsung Galaxy S/A series): *#0228# (shows voltage and temperature in real time).

In the engineering menu, pay attention to:

• MB_06 — current capacity in mAh (for example, 4500 instead of passport data 5000).
• Voltage — voltage (norm: 3.8–4.2 V at 100% charge).
• Temp — temperature (critically above 45°C).

What to do if the engineering menu does not open?

On some firmware (for example, MIUI Global or ColorOS) An alternative is to use the application MTK Engineering Mode (for Mediatek) or Shortcut Master to find hidden menus.

4. ADB commands: precise data for advanced users

Android Debug Bridge (ADB) is a debugging tool that allows you to read data directly from the battery controller. The method requires PC and switched on USB debugging, but gives the most accurate results.

Step-by-step guide:

1. Download ADB Tools and extract to your computer.
2. Turn on on your phone Settings → About phone → Build number (press 7 times) → return to Settings → System → For developers and activate USB debugging.
3. Connect the phone to the PC and in the command line (in the folder with ADB) enter:

   adb shell
   dumpsys battery

In the output, find the lines:

• charge counter — current capacity in mAh (divide by 1000 for mAh).
• capacity — the percentage of charge that the system shows (may differ from the real one).
• health — condition (2 = good, 3 = worn out).

Example output for Google Pixel 6:

charge counter: 3850000 (3850 mAh)
capacity: 77
health: 3

This means that the actual capacity has dropped to 3850 mAh (with a rated capacity of 4614 mAh), and the condition is rated as "poor."

⚠️ Attention: On some devices (for example, Huawei s EMUI) ADB-commands may be limited. In this case, it will only help root.

5. Discharge test: how to measure real capacity without apps

If applications do not trust you or you want to double-check the data, use manual discharge test. The method is long (will take 6–12 hours), but accurate.

Instructions:

1. Charge the phone to 100% and unplug it.
2. Turn on airplane mode and run YouTube at minimum brightness (video at 720p, sound at 50%).
3. Tick the time until complete discharge (for example, 8 hours).
4. Multiply the current consumption (measured AccuBattery or CPU-Z) for a while. For example: 500 mA × 8 h = 4000 mAh —real capacity.

Compare the result with the passport capacity:

Difference	Battery condition	Recommendations
0–10%	Excellent	Continue to use
10–20%	Satisfactory	Keep an eye on temperatures
20–30%	Poor	Get ready to replace
More than 30%	Critical	Replace the battery

6. Hardware diagnostics: USB testers and multimeters

For maximum accuracy, use external devices:

• 🔌 USB tester (for example, UM24C or VC830L) - connects between the charger and the phone, shows current, voltage and capacity in real time. Cost: 500–2000 ₽.
• 📟 Multimeter - measures the voltage at the battery contacts (disassembly required phone). Normal: 3.7–4.2 V at 100% charge.

How to use a USB tester:

1. Connect the tester to the charger and the phone to the tester.
2. Charge the battery until 100% and look at the value mAh on the tester screen - this is the real capacity.
3. Compare with the passport data (for example, 4500 mAh instead of 5000 mAh = wear 10%).

Advantages of the method:

• ✅ Accuracy ±1–2%.
• ✅ Works on any device, even locked ones bootloader.
• ✅ Shows internal resistance batteries (a high value is a sign of wear).

⚠️ Attention: Cheap USB testers (up to 500 ₽) often lie with the capacity. Choose models with calibration and accuracy reviews.

7. When it's time to change the battery: signs and threshold values

Even if tests show 15-20% wear, the battery can last another year or two. But there are critical signs in which replacement cannot be postponed:

• 🔥 The phone overheats when charging (above 50°C) or the case swells.
• ⚡ Battery discharges by 50% in 1-2 hours in standby mode.
• 📉 Capacity has dropped lower 60% of the passport (for example, 3000 mAh instead 5000 mAh).
• 🔌 Phone does not turn on without connection to charging or turns off at 20–30% charge.

Replacement cost:

Device	Battery price (₽)	Work price (₽)
Samsung Galaxy A52	1200–1800	800–1500
Xiaomi Redmi Note 10 Pro	900–1400	600–1200
Google Pixel 6	2500–3500	1500–2000
iPhone (for comparison)	2000–4000	1000–2500

Where to replace:

• 🛠️ Official service - 6-12 month warranty, but more expensive.
• 🔧 Unofficial workshops - cheaper, but the risk of a low-quality battery.
• 🏠 On your own - only if you have experience in disassembling (there are guides for each model). YouTube there are guides for each model).

FAQ: Frequently asked questions about checking the Android battery

Is it possible to restore the battery capacity without replacement?

Partially - yes. Methods:

• 🔄 Calibration: Discharge your phone to 0%, then charge it to 100% without interruption. Repeat 2-3 times.
• ❄️ Cooling: do not use the phone while charging and avoid direct sunlight.
• 🔌 Slow charging: use 5W charging instead of fast charging (18W+) to reduce wear.

These methods can return 5-10% of the capacity, but will not replace physically worn out elements.

Why does AccuBattery show a capacity of 6000 mAh, although the passport capacity is 5000?

This is a calibration error. The application calculates the capacity based on charging time, but if:

• You interrupted charging at 80% and brought it up to 100% later,
• You used non-original charging with an unstable current,
• The phone was turned off while charging,

then the data will be inaccurate. Solution: reset the statistics to AccuBattery and carry out 2-3 full charging cycles.

How to check the battery on a phone with a non-removable battery?

All methods from the article (except for the multimeter) also work for non-removable batteries. If you need to measure voltage or resistance:

1. Disassemble the phone (on YouTube there are guides for your model).
2. Connect the multimeter to the battery contacts (plus and minus).
3. Compare with the nameplate values (for example, 3.85 V for 50% charge).

⚠️ Risk: during disassembly, the cables or display can be damaged. If you have no experience, contact the service.

Is it true that fast charging ruins the battery?

Yes, but not critical. Research shows that:

• 🔋 Fast charging (18W+) increases temperature batteries, which accelerates degradation by 10-15% per year.
• ⚡ However, modern controllers (in Samsung, Xiaomi, Oppo) limit the current after 80%, reducing harm.
• 🛠️ Recommendation: use fast charging only when urgently needed, and for everyday use - 5W/10W.

What to do if the phone turns off at 30–40% charge?

This is a sign extreme wear or incorrect calibration. Procedure:

1. Check the actual capacity using one of the methods above. If wear is >30%, replacement is needed.
2. If the capacity is normal, perform reset the calibration:

   adb shell
   su
   rm /data/system/batterystats.bin

   (requires root).

3. Check battery contacts - sometimes oxidation is caused by false shutdown.