How to know the exact charge of Xiaomi’s superbank: all working ways

Xiaomi's powerbanks have long been the standard for portable chargers, thanks to a combination of compactness, capacity and affordable price. But even for powerbank powerbank powerbank users, how do you know the current battery level when there's no display? It turns out the manufacturer has provided several ways, from the simplest to the most advanced, requiring additional devices.

In this article, we’ll look at all the current charging testing methods for Mi Power Bank, Redmi Power Bank and other brands, including hidden features and life hacks. You’ll learn how to interpret flashing indicators, which apps really work with Xiaomi’s superbanks, and why sometimes the performance on the smartphone screen does not match the actual charge level.

1. Standard method: button and LED indicators

Most Xiaomi models feature a physical button and 2-4 LEDs that signal a charge level, a method that does not require a smartphone or PC connection, but has limitations on accuracy.

To check the charge:

• 🔋 Press the power button once (usually located on the end of the case).
• 💡 Calculate the number of lighted indicators:

An important nuance: USB-C models (such as Mi Power Bank 3 Pro) can go out 5 seconds after you press them. If you don't have time to count, press the button again.

⚠️ Note: Xiaomi is older than 2018 on the Verbank (e.g. Mi Power Bank 2) 20000mAh) indicators show a level in increments of 25%, but the real charge may differ by ±10% due to battery wear.

2. Checking through a smartphone: applications and OTG-cable

If you need accurate numbers (for example, 63% instead of “half”), you can connect the overbank to your smartphone via a phone. OTG-Adapter and specialized applications, which doesn't work on all models, but it gives you the most detail.

Step-by-step:

1. Download one of the apps: 📱 AccuBattery (shows voltage and capacity) 🔋 Power Bank Tester (specialized for superbanks) 📊 Ampere (displays charge/discharge current)

OTG-transmitter

Micro-USB/USB-C → USB-A

Launch the application and wait for the device definition.

Suitable OTG-Adapter (for example, the original from Xiaomi)

Installed application (AccuBattery or analogues)

Charge of the smartphone is not lower than 30% (to avoid parasitic discharge)

Battery optimization disabled for selected application-->

Limitations of the method:

• ❌ Does not work with superbanks that have disabled data transmission USB (For example, some Redmi models).
• ❌ iPhone will require additional lightning → USB-A Adapter and jailbreak for full-time work.
• ⚠️ Indications can be distorted if the overbank simultaneously charges the smartphone.

💡

If the app doesn’t see the overbank, try plugging it into charging for 10 seconds and then back into the smartphone.

3. USB-Tester: Professional Method for Accurate Data

For those who want to know the voltage, current strength and real capacity of the overbank, it is suitable. USB-The tester is a compact device that connects between charging and the overbank, a technique that engineers and enthusiasts use to diagnose batteries.

How to use:

1. Connect the tester to the superbank via USB-A → USB-C/Micro-USB (depending on the model).
2. Connect the charger to the tester.
3. The tester screen will show up: 🔋 V is voltage (norm for Li-ion: 3.7–4.2V cell-wise). ⚡ A is the current strength (shows how much ampres the overbank consumes when charging). 📊 mAh - real capacity (may differ from the declared by 10-15%).

Popular tester models compatible with Xiaomi:

• 🔌 Xiaomi USB Tester (original, but rarely available on sale).
• 📈 UM24C (shows the graphs of the discharge, suitable for testing powerbank).
• 💡 ZB2L3 (budgetary option OLED-display).

⚠️ Warning: If the tester shows voltage below 3.5V on the cell, this is a sign of a deep discharge - such a superbank must be urgently charged, otherwise the battery degrades.

4. Hidden functions: double pressing and button combinations

Few people know, but some Xiaomi models support hidden diagnostic modes that allow you to get advanced information about the battery.

Methods of activation:

• 🔄 Double-click button: On some superbanks (e.g. Mi Power Bank 3) 20000mAh) fast double pressing includes a test mode where the indicators flash at a different frequency, showing the exact percentage of charge (see the decoding in the instructions for the model).
• 🔌 Connection to PC: When connecting to a computer through USB-C The verbank can be defined as HID-The Mi Power Bank Tool (unofficial utility) can be used to read the controller data.

Importantly, these techniques can reset the charge cycle statistics or temporarily disable the overcharge protection. Don't use them unnecessarily!

💡

Hidden modes do not work on all models and may differ depending on the version of the controller firmware. If the superbank has stopped responding to presses, reset by holding the 10+ second button.

5 Mistakes and False Testimony: Why Verbank Lies

Sometimes the lights show 100% charge, but the power bank discharges in a few minutes, or vice versa, only 1 LED burns, even though the device lasts for hours, this is due to a malfunction of the controller or wear of the battery.

Common reasons for false testimony:

• 🔋 Battery dissection: Cells lose contact and controller doesn’t see part of capacity.
• 📉 Calibration reset: After deep discharge, the overbank may show an incorrect level until it is fully recharged (3-5 cycles).
• 🔌 Firmware problems: In rare cases, the controller “hangs” and requires flashing (possibly only in the service center).

How to check if the verbank is lying:

1. Completely discharge it (before turning off the indicators).
2. Charge with the original Xiaomi cable to 100% (all LEDs are green).
3. Put it on your smartphone and record the charging time, and if it's 30 percent+ less than you'd expect, the capacity drops.

⚠️ Note: If Xiaomi’s over 3-year-old superbank has fallen below 60% of its declared capacity, do not keep it fully charged, which will accelerate degradation.Optimum level for long-term storage: 40-60%.

6. Alternative methods: scales, multimeter and calculations

If you're not on hand USB-You can use the old-fashioned methods of a tester or a smartphone, which are less accurate, but sometimes they work in the field.

Method 1: Weighing

Lithium-ion battery capacity correlates with weight. Weigh the overbank on a kitchen scale and compare it to passport data:

• 📦 Mi Power Bank 2 10000mAh: ~220g (full charge) vs ~200g (discharged).
• 📦 Redmi Power Bank 20000mAh: ~400g vs. ~360g.

Method 2: Multimeter

If you have a multimeter, measure the voltage on the contacts. USB-port (red probe — +5V, black — GND). Normal values:

• 🔋 4.8–5.0V — charge close to 100%.
• 🔋 4.2–4.7V — middle-level.
• 🔋 Below. 3.7V — critical discharge.

Method 3: Calculation by charging time

Charge the power bank from a network with a known current (for example, from charging Xiaomi at 18W) and record the time.

Capacity (mAh) = Charging Current (mA) × Time (hours) × efficiency (0.85–0.9)

Example: if the 2A (2000 mA) charge was 5 hours, then its real capacity is ≈ 2000 × 5 × 0.9 = 9000 mAh (including losses).

FAQ: Frequent questions about the charge of Xiaomi's superbanks