Why Xiaomi Redmi Note 8 is Slowly Charging: 10 Reasons and How to Speed Up Charging

If your Xiaomi Redmi Note 8 is charging 2-3 times longer than usual, it doesn't always mean that the battery is out of order. In 70% of cases, the problem is software settings, poor accessories or trivial contamination of the connector. But how do you tell a temporary failure from a serious failure? And most importantly, what do you do about it?

In this article, we'll look at all the possible causes of slow charging, from the most obvious to the hidden, how to check every element of the charging circuit, from the power supply to the battery controller, and how to get step-by-step instructions for troubleshooting. Spoiler: 9 out of 10 cases, the problem can be solved without going to the service center.

The Redmi Note 8 features support for Quick Charge 3.0 (18W), but even with the original charger, the speed can drop to 5-10W. This is a malfunction signal. Next, you will find a table of normal current and voltage values for this model, as well as a test to determine whether the battery is to blame or something else.

1. Checking of charger and cable

Start with the simplest: 40% Slow charging problems are associated with poor quality or damaged accessories.Original Xiaomi power supply for Redmi Note 8 giveaway 5V/3A, 9V/2A or 12V/1.5A depending on fast charging support, if you're using left-handed RAM with parameters 5V/1A, The phone will charge in 2–3 slower.

How to check:

1. Connect the Redmi Note 8 to another charger (preferably an original one from Xiaomi or one with Quick Charge 3.0 support).
2. Use the cable. USB Type-C no longer than 1 meter long – long cables lose up to 30% of power.
3. Look at the charging indicator: if the lightning icon (⚡) No, no, no fast charging is activated.

⚠️ Caution: Cheap thin-vein cables can not only slow charging, but also damage the smartphone’s power controller. It is especially dangerous to use cables from older devices with a Micro-USB connector connected via an adapter.

To accurately measure charging power, install the AccuBattery app (available on Google Play) that will show real voltage and current. Normal values for the Redmi Note 8 when fast charging:

If the app is below normal, the problem is exactly in the power supply or the cable. Try charging the phone from the computer - if the speed is the same low, the cable is to blame.

2.Contamination of the USB-C connector: how to clean without damage

Connector. USB Type-C in the Redmi Note 8 is one of the most vulnerable places. Dust, pile from pockets, oxidation of contacts or even moisture can lead to poor contact and, as a result, slow charging. In this case, the phone can be periodically recharged (that is, then not), or charging stops altogether at the slightest movement of the cable.

Signs of a contaminated connector:

• 🔌 The phone is charged only in a certain position of the cable.
• 📉 Charging speed drops 5-10 minutes after connection.
• ⚠️ A notice appears "Moisture in the connector" (even if it is not there).
• 🔋 Charging is interrupted when vibrating or pressing the screen.

How to clean the connector without the risk of damaging the contacts:

1. Turn off the phone and remove it. SIM-memory-card.
2. Light the connector with a flashlight – if debris is visible, use a plastic toothpick (not metal!) or compressed air (a canister for cleaning equipment).
3. For oxidized contacts, moisten the cotton swab in isopropyl alcohol (90%+) and gently wipe the inside of the connector.
4. Let the phone dry for 10-15 minutes before connecting the charger.

⚠️ Warning: Never use needles, pins or other metal objects, they may bend contacts or close a chain. If after cleaning the problem remains, the connector may be mechanically damaged (for example, after falling) and require replacement.

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To prevent dust from getting in, use special plugs for the connector. USB-C (They are sold in phone repair kits).

Battery wear: how to check and what to do

The average battery life of the Redmi Note 8 is 3-4 years (or 500-800 full charge cycles), after which the battery capacity decreases by 20-30%, and the charging speed drops due to increased internal drag. If your phone is older than 2020 and charges slowly even with the original RAM, the battery is most likely to blame.

How to check the status of the battery:

1. Go to Settings. → Battery status (on some firmware path: Settings) → Battery → Battery status).
2. Look at the Capacity option – if it is below 80% of the original value (4000 mAh), it is time to change the battery.
3. Use the app. CPU-Z (Battery tab to check temperature and voltage, normal voltage at 100% charge 4.35-4.4 V.

Signs of a worn-out battery:

• 🔋 The phone will run out in 3-4 hours with normal use.
• 📈 Charging stops at 80-90% and does not go further.
• 🔥 The phone warms up strongly during charging (over 40)°C).
• ⚡ The charging speed drops after 50% (e.g. from 18 W to 5 W).

If the battery is worn out, it can be replaced yourself (the cost of a new battery is about 1000-1500 rubles), but consider:

⚠️ Note: When replacing the battery in an unofficial service, Xiaomi may block the fast charging function. To avoid this, after replacing, reset the settings through Settings → Additionally. → Recovery and discharge.

4. Software failures: optimization and resetting of settings

Sometimes slow charging is not due to hardware, but to software limitations, such as after a firmware update. MIUI The fast charging setting may reset, or background processes load the processor, which causes the phone to limit current.

What to check first:

• 🔧 Go to Settings. → Battery → Battery settings and make sure the Quick Charging option is enabled".
• 📱 Close all applications through recent tasks – some games (e.g. Genshin Impact or PUBG) Block fast charging during operation.
• 🔄 Restart your phone – sometimes it resets the system’s time constraints.

If nothing helps, reset your battery settings:

1. Go to Settings → Applications → Application Management.
2. Click on the three dots in the top right corner and select "Reset App Settings."
3. Confirm the action and restart the phone.

In extreme cases, a hard reset (with loss of data) will help:

1. Create a backup through Settings → Additional → Backup and Reset.
2. Go to Settings → About the phone → Reset settings.
3. Select “Erase all data” and wait until the process is complete.

⚠️ Note: After reset, you may need to re-activate Quick Charge in the battery settings. Also check if energy saving profiles are installed in Settings → Battery → Power regimens.

Is fast charging enabled in the settings?|Whether background applications are closed?|Have you tried a reboot?|Is the battery settings resetting performed?-->

5.Overheating: Why the phone slows charging when heated

Redmi Note 8 automatically reduces charging speed if the battery temperature exceeds 40°C. This is protection against battery damage, but sometimes it works falsely – for example, if the temperature sensor is contaminated or the phone is used in hot climates.

Causes of overheating:

• 🌡️ Charging in the sun or in a stuffy room.
• 🎮 Games or videos while charging (loading on the Snapdragon 665 processor increases the temperature).
• 🔋 Failed battery or power controller.
• 📱 Case blocking heat sink (especially silicone or thick models).

How to eliminate:

1. Remove the case before charging.
2. Charge your phone in a ventilated room (not on a bed or sofa – this blocks ventilation).
3. Do not use your phone to play games or watch videos while charging.
4. If the phone is warming even in standby mode, check the temperature sensor (it may require firmware or repair).

To check the temperature in real time, install the app AIDA64 (Sensors" section. Normal values:

• 🟢 Up to 35.°C – optimal for fast charging.
• 🟡 35–40°C – charging speed can decrease by 20-30%.
• 🔴 Above 40.°C – Charging is limited to 5 watts or shuts down completely.

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If the phone is hotter than 45°C, immediately disconnect it from charging. Prolonged overheating can cause permanent battery damage or even fire (in rare cases).

6. Problems with firmware and power controller

In rare cases, slow charging is associated with a firmware failure or a malfunction of the power controller (the circuit responsible for power distribution). MIUI, "Firmware" via Fastboot or physical damage to the board (for example, after a fall).

Signs of software failure:

• 📱 Phone shows "No Charging Supported" when connected to any RAM.
• 🔄 The charging speed jumps (it is 18 watts, then 5 watts for no reason).
• 🔋 The battery is discharged even during charging (for example, when the screen is turned on).
• 📉 AccuBattery displays an error called “Unknown power source".

Decisions:

1. Update your firmware: Go to Settings → About Phone → System Update and install the latest version of MIUI.
2. Fastboot: If the update didn’t work, download the official firmware from Xiaomi’s website and run through the Mi Flash Tool.
3. Check the power controller: If the phone doesn’t respond to charging at all, the chip may have burned (e.g., the chip is not on fire, BQ25601D In this case, you need repairs at the service center.

⚠️ Warning: If you are unsure of your skills, do not try to query the phone yourself.Incorrect actions can lead to a "brick" (completely inoperable) device.

Test commands can be used to diagnose the power controller ADB:

adb shell dumpsys battery


adb shell cat /sys/class/power_supply/battery/uevent

If there are lines in the conclusion like charge_type=Unknown or status=Discharging with connected charging, the problem is precisely in the controller.

7. Mechanical damage: falls, water, battery bloating

Physical injuries are one of the most serious causes of slow charging, and even a slight drop can damage:

• 🔌 Connector contacts USB-C (microcrack).
• 🔋 Battery soldering to motherboard.
• 📱 Power controller or charging circuit.

How to diagnose:

1. Examine the body for dents, cracks or traces of impacts.
2. Check if the battery is swelling - to do this, put the phone on a flat surface and spin: if it "swings", the battery is deformed.
3. Light the flashlight in the connector USB-C — If the contacts are bent or missing, repair is required.

If the phone fell into the water (even briefly), the contacts could oxidize.

1. Turn off the device immediately and remove it. SIM-map.
2. Place your phone in a silica gel (or rice) bag for 24 to 48 hours.
3. Do not turn it on until it is completely dry!
4. After drying, clean the connector with alcohol (as described in Section 2).

⚠️ Warning: If the phone stops turning on after falling or getting water, do not connect it to charging - this can cause a short circuit.

8. Alternative charging methods: what to do if nothing helps

If you’ve tried everything, but the Redmi Note 8 still charges slowly, try these methods:

Wireless charging (if supported):

• 📱 Redmi Note 8 does not have built-in wireless charging, but you can use a receiver Qi (connects to the connector). USB-C). Speeds will be lower (up to 10W), but it’s better than 5W cable.

Charging from power bank:

• 🔋 Some external batteries (such as Xiaomi Mi Power Bank 3) support Quick Charge 3.0 and can charge your phone faster than a standard RAM.

Aircraft mode:

• ✈️ Turn on the mode of the aircraft while charging - this will turn off background processes and speed up charging by 10-15%.

Replacement of the connector USB-C:

• 🔧 If the connector contacts are damaged, it can be replaced in the service (cost is about 800-1500 rubles), which is cheaper than changing the motherboard.

Castom firmware:

• 📲 Some custom firmware (like LineageOS or Pixel Experience) optimize power management better than stockware. MIUI. But keep in mind: this voids the warranty and requires unlocking the bootloader.

If none of these methods worked, there are two options:

1. Contact the Xiaomi service center (official repairs will cost 2000-4000 rubles).
2. Buy a new battery and replace it yourself (video instructions are available on YouTube).

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Before visiting the service, make a backup copy of the data through Settings → Additionally. → Backup: Some faults (e.g., controller failure) require a complete phone reset.

FAQ: Frequent questions about the Redmi Note’s slow charging 8