Why fast charging on Xiaomi Redmi Note 8 Pro stopped working – diagnostics and repair

Xiaomi Redmi Note 8 Pro with its powerful processor Mediatek Helio G90T and a capacious battery 4500 mAh initially supports fast charging 18W. But over time, many users face a problem: the phone charges 2-3 times longer, although previously 100% gained in an hour. The reasons can lie in hardware malfunctions and software failures. In this article, we will analyze all possible scenarios – from banal wear of the cable to hidden firmware settings that block high power.

It's important to understand that if the Redmi Note 8 Pro suddenly stopped charging fast, it doesn't always mean that it's broken. Sometimes the fault is the careful charge algorithm that Xiaomi has implemented in recent MIUI updates. And in some cases, the problem lies in the power controller, the chip responsible for power distribution. We have put together proven diagnostic methods and solutions that will help to return the original charging speed without going to the service center.

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

The first thing to rule out is a charging unit or cable malfunction, and even Xiaomi's original accessories wear out over time, especially if you often bend the wire or plug your phone in wet conditions.

• 🔌 Try charging the Redmi Note 8 Pro with another Quick Charge 3.0 or Power Delivery charger (like a MacBook or Samsung). If the speed returns, your power supply is a problem.
• 🔄 Use a different cable. USB Type-C. Cheap uncertified wires often do not support high currents, limiting charging to 5W.
• 📱 Connect your charger to another phone (preferably with a quick charge) if it works properly, it's your Redmi's connector or power controller that's to blame.

Pay special attention to the Type-C connector on your phone, which eventually gets clogged with dust and debris, which worsens contact, carefully clean it with a toothpick (not a metal object!) or compressed air, if the phone detects it as "charging" instead of "fast charging" when connecting the cable, this is a clear sign of poor contact.

⚠️ Warning: Never use alcohol or liquids to clean the connector! Moisture on the contacts can cause corrosion and completely disable the port.

2. Software glitches: why MIUI blocks fast charging

Xiaomi is actively implementing battery life extension features that sometimes conflict with fast charging. Recent MIUI (starting with MIUI 12.5) has introduced a hidden mechanism called Adaptive Charging, which automatically limits current under certain conditions.

1. Go to Settings → Battery and Performance → Battery settings.
2. Find the "Fast Charging" item (in some firmware it is hidden - see spoiler below).
3. Make sure the switch is active. If it's not there, it's disabled at the core level.

If there is no obvious switch in the menu, try resetting the battery settings:

Settings → Battery → ⋮ (menu) → Reset battery statistics

Another common reason is background processes that consume energy while charging, run Safe Mode (hold the shutdown button → Safe Mode) and check the charging speed, and if it's recovered, one of the installed applications is to blame.

• 🔋 Battery saving applications (e.g. Greenify, AccuBattery).
• 🎮 Gaming Utilities (Game Turbo) MIUI Sometimes it blocks high power).
• 🛡️ Antiviruses with the function of "charging optimization".

Battery wear: when the battery is no longer pulling 18W

The Lithium Polymer batteries in the Redmi Note 8 Pro are designed for 500-800 charging cycles, after which the capacity drops by 20-30%, and the power controller automatically reduces the maximum current to prevent overheating.

1. Using the diagnostic menu: ##4636## → Battery → Charge level and status If the status of “Good” changed to “Replace soon” – the battery is worn out.
2. AccuBattery: it shows the actual capacity and the number of cycles, and if the current capacity is less than 3,500 mAh, it's time to think about replacing.

The critical threshold for the Redmi Note 8 Pro is a drop in capacity below 60% of the original (2700 mAh), in which case the power controller blocks fast charging at the firmware level, even if you are using the original unit. 18W. The only solution is to replace the battery, and the cost of the original battery for this model is about 1,500 to 2,000. ₽ fittingly.

⚠️ If you decide to replace the battery yourself, use only the original Xiaomi battery. BM47 (articular MB-J20BR). Cheap analogues often do not support fast charging and can swell over time.

4.Overheating phone: why charging slows at high heat

The Redmi Note 8 Pro is equipped with a thermal throttle system that automatically reduces the charging power when overheated. The normal operating temperature of the battery is 25-40 ° C. If the sensors record values above 45 ° C, the power controller limits the current to 5-10W to avoid battery degradation.

How to check the temperature:

• 🌡️ Install the app AIDA64 or CPU Monitor – They show the battery temperature in real time.
• 🔥 If the phone is hotter than 42°C while charging, remove the case and place it on a flat surface (not on the bed or sofa!).
• ❄️ Avoid charging in the sun or in a stuffy room, with an optimal ambient temperature of 20-25°C.

Frequent causes of overheating:

• 🎮 Games or resource-intensive applications during charging (e.g, PUBG Mobile or Genshin Impact).
• 🔄 Simultaneous charging and wireless data transfer (Wi-Fi, Bluetooth, GPS).
• 🛠️ Clogged radiator or thermal paste (relevant after 2-3 years of use).

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If your phone is getting too hot, try turning on Battery Savings mode while charging, which will reduce the processor load and speed up the process, despite the apparent inconsistency.

5. Resetting and flashing: radical methods

If all the previous steps didn't work, the problem could be in the system files that control power, in which case resetting or flashing will help, starting with the safest option, resetting to factory settings:

Make a backup copy of the data (photos, contacts, SMS)

Remember the username and password from the Mi Account

Make sure the battery is at least 50% charged.

Disable Google Account (Settings) → Accounts)-->

Resetting instructions:

1. Go to Settings → About the phone → Reset settings.
2. Select “Reset all settings” (does not delete files) or “Delete all data” (complete cleaning).
3. Confirm the action and wait for the reboot.

If the reset doesn't work, you'll have to go through the phone. For the Redmi Note 8 Pro, the official firmware through the Mi Flash Tool will do:

1. Download the latest version of MIUI for your model from en.miui.com.
2. Install the Mi Flash Tool on your PC and connect your phone in Fastboot mode (keep Volume down + Power on).
3. Select the firmware file and press "Flash".

⚠️ Warning: Firmware deletes all data and can lock your phone if you haven't untied your Mi Account in advance.Don't use informal firmware - they often break fast charging support!

6. Hardware malfunctions: when without service can not do

If none of the software methods worked, the problem is likely to be hardware, and here are the most common breakdowns that require specialist intervention:

• 🔌 Faulty power controller (microchip) BQ25601D Symptoms: the phone does not detect charging at all or only charges when it is off.
• 🔋 Damaged walkways on the motherboard, often after falls or moisture, sign that charging is jerking or interrupted.
• 🔌 Oxidation of Type-C connector contacts. Green or white spots on the legs of the connector are visually noticeable.
• 🛠️ The battery circuit fails. The phone can show charging, but the battery doesn't really charge.

Cost of repair in the service center:

Before you bring your phone to the service, check whether it is not covered by the warranty. Even if the deadline has expired, some Xiaomi service centers are willing to meet when contacting the official website mi.com/service.

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If your phone stopped charging quickly after falling, getting moisture or disassembling itself, 90% of the problem is hardware. Don't waste time on software methods, just contact the service right away.

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

If you can’t recover fast charging, but the phone still holds the charge, you can use alternative methods to speed up the process:

• 🔌 Wireless charging 10W. Redmi Note 8 Pro does not support it out of the box, but you can buy an adapter Qi receiver (about 500). ₽). The speed will be lower, but there is no risk of damage to the connector.
• 🔋 Charging from Power Bank with Quick Charge.Some external batteries (e.g. Xiaomi Mi Power Bank 3 Pro) support 18W They can bypass the limitations of the phone.
• ⚡ Airplane mode: Shutting down the network reduces charging time by 15-20%, as the phone does not waste energy searching for a signal.

If you’re on the road a lot, consider a 20,000 mAh portable charger with Power Delivery support. For example, Baseus 65W or Anker PowerCore can charge the Redmi Note 8 Pro up to 50% in 30 minutes even with a worn-out battery.

FAQ: Frequent questions about fast charging Redmi Note 8 Pro