Xiaomi 8 phone does not charge when connected charging: full troubleshooting instructions

You plugged in a Xiaomi Mi 8 charger, but the battery light doesn't respond, and the percentage of charge stays in place or even falls? This problem is familiar to many owners of Xiaomi smartphones with 2-3 years of experience. In 80% of cases, it's not the fault of the board, but the trivial things: a contaminated connector, a damaged cable or a software failure. But how to accurately determine the cause and fix it without going to the service center?

In this article, we’ll look at all the possible reasons why the Xiaomi Mi 8 doesn’t charge when the charger is connected – from the most obvious to hidden hardware faults. You will receive step-by-step instructions with photos, charger compatibility tables, and tips for preventing battery problems. BQ25890 firmware MIUI.

1. Checking the charger and cable: where to start the diagnosis

The first thing to do is to eliminate power supply problems, which even if you were using Xiaomi's "native" kit, it could have failed, and according to service center statistics, 35 percent of non-charging cases are caused by a cable or an adapter.

Here's how to check correctly:

• 🔌 Connect another charger (preferably original from Xiaomi with Quick Charge 3.0 support). If charging started, the adapter is a problem.
• 📱 Try charging another phone with the same cable, and if it's not charging, the cable is damaged.
• 🔍 Check the USB-Type C connector on your phone in good light. whether you can see foreign objects, oxidation or bent contacts?
• 🔄 Turn the cable plug in the connector – sometimes the contact disappears due to wear on one side of the connector.

Note the power of the charger. Xiaomi Mi 8 supports fast charging Quick Charge 3.0 (18W), but will charge from standard 5V/2A adapters. However, if the power is below 10W (for example, charging from an old smartphone), the phone may not recognize the connection or charge extremely slowly.

⚠️ Never use cheap cables without certification USB-IF. They can damage the smartphone's power controller due to unstable voltage.It is especially dangerous to connect the Xiaomi Mi 8 to charges from laptops with higher voltages. 5V standardized USB-PD or QC.

2. Cleaning the charging connector: how to remove dirt and oxidation

The USB-Type C connector in the Xiaomi Mi 8 is one of the most vulnerable places, because of the frequent connection / disconnection of the cable inside, dust accumulates, fibers from clothes, and sometimes even metal shavings from worn connectors, which leads to poor contact and intermittent charging.

For cleaning, you will need:

• 🕯️ Toothpicking (wooden, non-metallic!)
• 🧴 Alcohol (isopropyl 90% or medical)
• 🧻 Cotton swabs (thin, for the ears)
• 🔦 Lantern (for lighting the connector)

Turn off the phone and remove it. SIM-map|Light the connector with a flashlight and inspect for debris.|Carefully remove visible contaminants with a toothpick (do not scratch the contacts!)|Wet the cotton swab in alcohol and wipe the internal contacts|Let the connector dry. 10-15 minutes before connecting the cable-->

If you see blackened or greenish contacts inside the connector, it's a sign of oxidation.

1. Wet the cotton swab in alcohol and gently rub the oxidized areas.
2. For strong oxidation, use an eraser (washing gum) - it will mechanically remove the oxide layer.
3. After cleaning, blow the connector with compressed air (you can use a canister to clean the keyboard).

After cleaning, try to plug in the charger. If the phone starts charging, the problem is solved. If not, move on to the next step.

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To prevent dust from entering the connector, use special plugs for Type-C (sold in phone repair kits).

3. Diagnostics of software failures: resetting and test mode

Sometimes the Xiaomi Mi 8 doesn’t charge due to firmware failures or application conflicts, especially after a MIUI update or custom firmware installation, software errors can block the power controller, causing the phone to fail to recognize the charger’s connection.

Try these methods:

Resetting settings to factory

This is a radical but effective way to eliminate software conflicts.Be sure to back up important data before resetting, as all applications and settings will be deleted.

Instructions:

1. Go to Settings → About Phone → Backup and Reset.
2. Select Settings Reset.
3. Confirm the action and wait for the reboot (it will take 5-10 minutes).

Test charging mode

Xiaomi Mi 8 has a hidden test mode that shows the real state of the power controller.

1. Turn off the phone.


2. Press the Volume Up + Power button and hold for 10 seconds.




3. Select Item Test → Charger Test from the menu.




4. Connect the charger.

In this mode, you'll see:

• 🔋 Current charging current (should be) 1000-1800 fast-charging).
• 🔌 Connection status (Charging or Not Charging).
• 📊 Battery voltage (normal: 3.7-4.2V).

If in test mode the phone shows Not Charging, but the cable and power supply are serviceable - the problem is in the hardware (power controller, battery or connector).

4. Problems with the battery: how to check its condition

Average battery life in Xiaomi Mi 8 — 2-3 year 500-800 After that, the battery capacity drops on the 30-50%, a the power controller may block charging due to critical wear.

Signs of a faulty battery:

• 🔋 The phone is charged only when it is off.
• 📉 The percentage of charge "jumps" (for example, from 50% immediately to 20%).
• 🔥 The body heats up in the battery area even without loading.
• ⚡ The phone turns off when 20-30% charge.

To check the status of the battery:

1. Install the AccuBattery app (available on Google Play).
2. Run a battery health test (Health section).
3. If you look at the Wear level, if it's above 30 percent, you should change the battery.

If the battery is worn out, it must be replaced. For Xiaomi Mi 8 suitable batteries labeled BM47 or BM48 capacity of 3400 mAh. The cost of the original battery is about 1500-2000 rubles, replacement in the service center will cost 1000-1500 rubles additionally.

⚠️ Warning: Don't buy cheap battery counterparts without certification. They can swell or ignite when charged. Xiaomi's original batteries have overheating and short circuit protection.

5. Power controller malfunctions: when a soldering station is needed

If all previous methods failed, the problem may lie in the power controller, the BQ25890 chip that controls battery charging. In the Xiaomi Mi 8, this chip often fails due to:

• ⚡ Voltage surges (low-quality chargers).
• 💦 Moisture in the USB-Type C connector.
• 🔥 Overheating of the phone (games, sunlight).
• 🛠️ Incorrect battery replacement (short circuit).

Symptoms of a faulty controller:

• 🔌 The phone is not charged from any cable/charging.
• 📱 When connected to a PC, it is defined as Unknown Device.
• 🔋 In test mode shows Charging: No despite the serviceable cable.
• 💥 The phone only turns on from the connected charge, but does not hold the charge.

Diagnostics and repair of the power controller require special equipment:

1. soldering of the new chip BQ25890 (the cost of the part: 300-500 rubles).
2. Checking the power chains with a multimeter (voltage at the contacts of the battery).
3. Flip-flashing EDL-mode (if the controller is "hang" due to a software failure).

The average cost of repair in the service center is 2500-4000 rubles. If you decide to repair yourself, you will need:

• Salting station with a temperature of 300-350 ° C.
• Flux RMA-223 and solder Sn63Pb37.
• Microscope or backlit magnifier.
• New BQ25890 chip (check compatibility with Mi 8 board revision)

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Self-repairing the power controller without experience can lead to a complete failure of the phone. If you are not sure about your skills, you should consult a specialist.

6. Alternative charging methods: if the standard method does not work

If the Xiaomi Mi 8 refuses to charge via the Type-C connector, alternative methods may be tried.They won't solve the problem forever, but will help "reanimate" the phone for data backup or temporary use.

Wireless charging

The Xiaomi Mi 8 does not support wireless charging out of the box, but you can use a Qi receiver that connects to a Type-C connector. For example, the Nillkin Magic Disk adapter or the Baseus Wireless Charger Receiver.

Instructions:

1. Connect the receiver to the phone connector.
2. Place your phone on a wireless charging station (at least 10W).
3. The charge will go slower, but it is better than nothing.

Charging through OTG-cable (reverse charging)

If you have an OTG-enabled Power Bank or other phone, you can try charging the Mi 8 backwards:

1. Connect. OTG-adapter for the Mi 8 connector.
2. Connect to the adapter cable from Power Bank (or other phone in OTG mode).
3. If the power controller is in good working order, charging will begin.

Charging through a disassembled cable

This method is extremely risky and only suitable in desperate situations, the point is to connect the plus and minus directly to the contacts of the battery, bypassing the power controller.

⚠️ Warning: This method can cause the battery to fire or damage the board. Use it only if the phone is not turning on and the data on it is critical. 4.2V, current 1A.

7.Prevention of charging problems: how to extend the life of the battery

To avoid charging problems in the future, follow these guidelines:

• 🔌 Use only certified cables with labels USB-IF.
• 📱 Do not allow full discharge of the battery (charge at the time of the battery). 10-20%).
• 🔥 Avoid overheating your phone (do not play heavy games while charging).
• 💧 Do not use your phone in wet conditions (bath, rain, snow).
• 🔋 Calibrate the battery every 3 months (full discharge/charging cycle).
• 🛠️ Clean the Type-C connector from dust regularly (once in a week) 2-3 month).

It is also useful to disable charging optimization in MIUI settings if it is enabled:

1. Go to Settings → Battery and Performance → Battery Settings
2. Turn off the option Adaptive Charging (it may interfere with the normal process).

By following these tips, you’ll extend the life of the Xiaomi Mi 8 battery by 1-2 years and avoid most charging problems.

Frequently asked questions