Why Xiaomi phone discharges on charging instead of charging: a full analysis of the problem

Introduction: The paradox of “reverse charging”

You plug Xiaomi into a charger, but instead of the usual increase in battery percentage, you see the opposite: the charge level drops, the phone runs out, and the charging indicator flashes or does not respond at all. The situation seems absurd - how can a device lose power when connected to a power source? In practice, this is one of the most common complaints of owners of Redmi, POCO and Mi smartphones in recent years.

The causes of this behavior fall into two large groups: hardware malfunctions (damaged cables, connectors, batteries) and software failures (background processes, firmware errors, incorrect settings). In 60% of cases, the problem is solved without visiting a service center — enough competent diagnosis and simple manipulation. However, ignoring the symptoms can lead to a complete failure of the battery or even fire risk (with short circuits in the power chain).

In this article, we will examine Xiaomi’s unique false-charging mechanism, where the power controller mistakenly recognizes the current as “incoming”, but in fact the battery continues to run out, you will learn how to distinguish a software glitch from a physical failure, what tools to use for diagnosis and when to carry the phone for repair.

1.A damaged cable or adapter: the main "culprits"

To start with, the most common charger is a faulty charger, and service center statistics show that 35 percent of the "reverse charging" is caused by cables or power supplies, because Xiaomi uses Quick Charge technology (in Redmi Note 10 and later Quick Charge 3.0+), which requires a stable voltage, and if the cable is damaged, the resistance in the circuit increases, and instead of charging, the phone starts to waste energy to compensate for losses.

How to check:

• 🔍 Visual inspection: bend the cable in places of frequent bends (at the connectors). If you see cracks or bare wires, replace it.
• 🔌 Test with another adapter: Take the original power supply from Xiaomi (at least 18W) and check charging.
• 📊 Ammeter Check: If you have one USB-Tester, measure the actual current. ≥1.5A (for rapid charging — ≥2.5A).

Note that cheap cables from AliExpress often have thin veins that can’t withstand the currents of Quick Charge, which leads to a paradoxical situation: the phone recognizes the connection to the network, but in fact does not receive enough power, continuing to discharge from the background processes.

⚠️ Warning: If the phone gets too hot in the area of the connector when charging, turn it off immediately.

2.Contaminated or damaged USB-C connector

The USB-Type C connector in Xiaomi smartphones is one of the most vulnerable places, with dust, pocket pile, moisture or mechanical damage to the contacts leading to unstable connections.

• 🔄 Contact is now appearing, then disappearing – the phone “thinks” that the charging is connected, but the current does not come.
• ⚡ Micro-locks occur, which causes the power controller to block charging as "unsafe».
• 📉 The battery discharges faster than it can charge (especially noticeable when the screen is turned on).

How to clean the connector:

1. Turn off the phone and remove it. SIM-memory-card.
2. Take a wooden toothpick (not metal!) and carefully remove visible debris.
3. Blow the connector with compressed air (a canister for cleaning equipment).
4. If the contacts are oxidized, wipe them with alcohol (70% and above) with a cotton swab.

For models POCO X3, Redmi Note 9 and older is characterized by the problem of "falling off" connector — it physically wobbles in the case. This is a factory defect, and here it will help only to replace the connector in the service (cost). ~1500–2500 ₽).

3. worn-out battery: when the battery "fails" to charge

The lithium polymer batteries in Xiaomi smartphones are designed for 500-800 charging cycles, after which the capacity drops by 30-50%, and the power controller begins to behave unpredictable.

• 🔋 The phone shows 100% charge, but turns off at 30-40%.
• ⚡ When you connect charging, the percentage first falls, and then slowly grows.
• 🔥 The body is strongly warmed in the battery area (even without loading).

Check the status of the battery through the engineering menu:

Enter the phone code in the app: ##4636##


Go to the tab "Battery Information"

If you look at Battery Health, you have to change the battery if it's below 70 percent.

For Xiaomi 11T, Redmi K40 and newer models, the problem of battery bloating is relevant. If the phone body becomes convex and the screen “steps away” from the frame, immediately turn off the device and do not use it!

4. Software failures: when firmware is to blame

MIUI (especially in versions 12-14) is known for power management bugs, and the most common causes of “rechargeback” are:

• 🤖 Mediaserver – Responsible for multimedia, but sometimes consumes up to 50% CPU, discharge the battery faster than it is charged.
• 🔄 Battery Stats malfunction – the system miscalculates the remaining charge, showing a false decrease in interest rates.
• 📱 Conflict with the shell MIUI — After the updates, some models (Redmi) 9A, POCO M3) Begin to “glutch” with the display of charging.

How to fix it:

1. Restart your phone in Safe Mode (press the power button → Safe Mode) If charging is going well, the third-party app is to blame.
2. Reset settings via Settings → System → Reset settings → Reset all settings (does not delete files!).
3. Update your firmware to the latest version via Settings → About Phone → System Update.

If the problem has occurred after the MIUI update, try to roll back to the previous version via Fastboot.

1. Download firmware from https://xiaomifirmwareupdater.com/


2 Unlock the bootloader (via Mi Unlock Tool)




3. Sweat through the Mi Flash Tool in "clean all" mode.

5. Background processes and "gluttonous" applications

Even when charging, the phone can run out if the background tasks consume more power than the adapter.

• 🎮 Games (Genshin Impact, PUBG Mobile – when connected charging can discharge the battery by 1-2% per minute.
• 📷 Camera in 4K — permission-recording 3840×2160 require 1.5And the current.
• 📡 Mobile Internet 5G — Snapdragon 8 Gen 1 Module (in Xiaomi 12, POCO F4) It heats up and consumes up to 30% of the charge per hour.
• 🔄 Auto-Update Apps – Google Play and Mi App Store can run updates in the background.

How to find and disable “gluttonous” applications:

1. Open Settings → Battery → Battery Use.
2. Sort the list by decreasing consumption.
3. Click on the app. → «Limit background activity».

💡

If the phone is discharged while charging during the game, turn on the developer settings (Settings → About Phone → MIUI version – press 7 times) option Do not turn off the screen while charging.

The MediaTek Helio G95 (Redmi Note 10S, POCO M4 Pro) has a bug that keeps the cores running at maximum frequency, causing overheating and discharging even with the adapter connected, so the solution is to reset the power saving settings to factory.

Failure of the power controller

Power Management IC (PMIC) is a chip that regulates battery charging and discharging. Xiaomi smartphones often use a Qualcomm PM660 chip (in Snapdragon 7xx/8xx models) or MediaTek MT6358.

• 🔌 Phone shows charging, but battery percentage drops.
• ⚡ Charging is only in the off state.
• 🔥 The body is heated in the upper part (where the controller is located).

Reasons for PMIC failure:

• ⚡ Voltage surges (for example, when using uncertified chargers).
• 💦 Moisture on the motherboard.
• 🔧 Failed repair (overheating during soldering).

Diagnosing a faulty controller can be based on the following signs:

⚠️ Warning: If the phone stops turning on after "recharge", do not try to charge it with "shocks" (repeatedly connecting / disconnecting the cable.

External factors: temperature, humidity, mechanical damage

Sometimes the reason is not the phone, but the environment. Let's look at three key factors:

Extreme temperatures:

• 🌡️ Low 0°C: Lithium polymer batteries stop taking charge.
• 🔥 Above 45.°C: Controller blocks charging to prevent bloating.

Humidity and corrosion:

• 💧 The ingestion of water in the connector or on the board leads to the oxidation of contacts.
• 🔋 Corrosion on the battery increases internal resistance, which is why it can not be charged.

Mechanical damage:

• 📱 Cracks on the body next to the charging connector can disrupt the power chain.
• 🔌 Falling the phone on the connector often leads to microcracks on the board.

If your phone has been in water, follow the algorithm:

1. Turn it off immediately and remove the battery (if possible).
2. Wet with a napkin, don't rub it!
3. Place your phone in a silica gel bag (out of a shoe box) for 24 to 48 hours.
4. Do not turn it on until you are sure of complete dryness!

💡

If the phone is wet, DO NOT in any case plug it into charging until it is completely dry! this can cause short circuit and permanent damage to the board.

FAQ: Frequent questions about Xiaomi’s charging discharge