Xiaomi Redmi Note 8 Pro with its powerful Mediatek Helio processor G90T And with a capacious 4,500 mAh battery, you can use Quick Charge 3.0 (18 watts) fast charging technology, but what if your smartphone suddenly stopped charging at its normal speed? Instead of the promised "50% in 30 minutes," you get a snail's pace or a normal charge? There can be a dozen reasons - from banal pollution of the port to serious hardware malfunctions.
In this article, we will look at all possible scenarios: why the Redmi Note 8 Pro does not take fast charging, how to diagnose the problem yourself and what to do to fix it. MIUI, And if you've tried to change the charger and it didn't work, you'll find solutions that aren't written in the standard instructions.
1. Checking the baseline conditions for fast charging
Before digging deeper, make sure you meet the minimum requirements for Quick Charge 3.0 activation on the Redmi Note 8 Pro. Many users miss these points by blaming the problem as a “breakdown.”
First, the original charger is not a whim of the manufacturer, but a prerequisite (5V/1A) or a cheap no-name adapter is physically unable to deliver the desired 9V/2A or 12V/1.5A. Even if the power supply says "Quick Charge", it does not guarantee compatibility with the Mediatek protocol used in Helio. G90T.
- 🔌 Charger: should support Quick Charge 3.0 or Mediatek Pump Express. Optimally - the original unit from Xiaomi (MDY-08-EM, 18W).
- 📱 Cable: only USB Type-C with high-current support (thick veins, labeled "Fast Charge"). Cables from older smartphones or cheap counterparts will not work.
- 🔋 Temperature: If the battery is overheated (>40°C) or supercooled (<5°C), the controller automatically reduces the current. Check the temperature in Settings → Battery.
- 📲 Charging mode: in MIUI There's a hidden option to limit current. More on that in the next section.
A simple test: connect your smartphone to charge and look at the lock screen. If you see the "Fast Charge" (or lightning icon) sign, it's not the power supply that's the problem. If you don't have the label, but it's charging, it's probably standard mode. 5V/2And.
2. Hidden settings MIUI, Quick Charge blocking
Xiaomi built into MIUI There are a few features that can artificially limit charging speeds, and one of them is the battery optimization mode, which is activated by default after the updates, and it reduces the charging current to reduce battery wear, but it turns off the Quick Charge.
To check and disable this mode:
- Go to Settings → Battery and Performance → Battery settings.
- Find the option “Optimize charging” (or “Battery protection” in the new versions). MIUI).
- Turn off the option “Enable optimization” or “Adaptive charging”.
- Reboot your smartphone.
Another hidden option is to limit the current on USB. It can work when you connect to uncertified accessories to reset the restriction:
- Connect the charger.
- Open the Settings. → The phone.
- 5 times press "Version" MIUI" (Developer mode activated).
- Return to the main settings, open "Advanced settings" → For developers".
- Find "Restriction of Charging" USB" and turn it off.
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If the charging is still slow after optimizing, try turning Flight mode on and off again for 10 seconds, which will reset the power controller's time constraints.
It's also worth checking background processes. If you run resource-intensive applications (games, navigation, video editing) during charging, the system can force the current to be reduced to avoid overheating. Close all applications and repeat the test.
Diagnostics of cable and connector USB-C
About 30 percent of the problems with fast charging on the Redmi Note 8 Pro are due to physical wear and tear on the cable or connector, and visually everything may look normal, but inside — cliffs or oxidation of contacts.
How to check the cable:
- 🔍 External inspection: bend the cable in different places, if you see cracks in the squirt or fractures, replace it.
- 📏 Resistance test: connect the cable to a known power supply and check the output voltage with a multimeter. Quick Charge should be 9V or 12V (not the standard 5V).
- 🔄 Check on another device: if the cable does not give fast charging even on another smartphone QC 3.0 - it's faulty.
How to check the connector USB-C smartphone:
- Put the charger on, and gently swing the cable in different directions, and if you get charging, it goes away, and the problem is the connector.
- Light a flashlight to the port. If you see foreign objects (dust, fibers, oxidation) - clean it with a plastic (not metal!) toothpick.
- Try connecting your smartphone to your computer, and if the data transmission is unstable, it's an indirect sign of connector problems.
What happens if you clean it? USB-metal-port?
If the connector is visually damaged (bent contacts, corrosion marks), it must be replaced. In service centers, this service costs from 1,500 to 3,000 rubles, depending on the region. Self-repair is not recommended - there is a high risk of damage to the fee.
Status of battery and power controller
Redmi Note 8 The Pro is equipped with a lithium polymer battery, which eventually degrades. 300-500 The charging cycles are reduced by 20-30%, And the internal resistance increases, and this causes the power controller to automatically lower the current to avoid overheating.
How to check the status of the battery:
- Install the AccuBattery app (available on Google Play).
- Charge your smartphone to 100% and discharge to 0% (no recharging!).
- Look at the current battery capacity in the Health section, if it's below 80 percent of its value (4,500 mAh), the battery is worn out.
- Pay attention to the voltage graph. If it jumps or falls below 3.5V at 20 percent charge, the battery needs to be replaced.
Another possible cause is a power controller malfunction (Mediatek chip) MT6358). He's responsible for power distribution and support for Quick Charge:
- 🔥 The smartphone is very warm even with normal charging.
- ⚡ Fast charging works in "snippets" (it turns on, then turns off).
- 📉 Charging is only in the off state.
- 🔄 The percentage of charge jumps (for example, from 50% drops to 20%).
If you suspect a controller, check it this way:
- Connect your smartphone to charge and measure the temperature of the case in the area of the camera (there is a chip). >50°C is a sign of a malfunction.
- Try charging your smartphone when it's off. If fast charging is working, the problem is with the firmware or the controller drivers.
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If the battery is worn out (<80% Fast charging can be automatically turned off by the system for safety. ~2 000 Rubles often solves the problem.
5. Software failures and resetting of settings
Quick Charge is sometimes disabled after an update. MIUI It's because of a power controller driver conflict or a kernel setting that's not right. If you've had a problem after the update, try the next steps:
Resetting charging settings:
- Go to Settings → System → Resetting settings.
- Select “Reset Battery Settings” (not to be confused with a full reset!).
- Confirm the action and restart the smartphone.
Cleaning the system cache:
- Turn off your smartphone.
- Press the Power button + Volume up to enter Recovery.
- Select "Wipe cache partition" (control - volume buttons, confirmation - power button).
- Reset the device.
If the failures began after the installation of custom Recovery (for example, TWRP) or firmware, possibly damaged files power_profile.xml or charger_switch. In this case, only the re-flashing of the official will help. MIUI via Fastboot:
fastboot flash all [name firmware].zip
fastboot rebootWarning: Faulty firmware can completely turn off charging. If after manipulations, the smartphone stopped charging at all, immediately contact the service.
Make a backup copy of the data (photos, contacts, messages)
Download the official firmware for Redmi Note 8 Pro (version should match the region!)
Charge your smartphone to at least 50%
Prepare a USB Type-C cable (preferably original)
Make sure that drivers are installed on the PC ADB/Fastboot-->
External factors: temperature, humidity, magnetic fields
Few people know, but fast charging on the Redmi Note 8 Pro can be turned off due to external conditions, which the system perceives as dangerous.
| Factor. | How does charging affect | Decision |
|---|---|---|
| Temperature. >40°C | The controller reduces the current to 5V/1To avoid damage to the battery. | Let your smartphone cool in the shade (not in the fridge!). |
| Temperature. <5°C | Lithium-ion batteries do not charge at low temperatures. | Move your smartphone to a warm room, wait. 10-15 minute. |
| Humidity >60% | Moisture sensor in USB-Port blocks charging (short-circuit risk). | Dry the port with a hair dryer (cold air!) or silica gel. |
| Magnetic fields | Strong magnets (such as in cases) can knock down the compass and sensors, leading to failures. | Remove the case and restart the smartphone. |
| Charging on a soft surface | Dense fabrics (sofa, bed) block ventilation, causing overheating. | Charge your smartphone on a hard surface (table, stand). |
Critical information: if the smartphone shows a warning "Moisture in the charging port", but the port is dry - it can be a false alarm of the sensor. USB-C service.
Also, fast charging can be turned off while working at the same time. GPS This is due to the limitations of the Mediatek Helio controller. G90T, which, at high load, prioritizes performance over charging.
7 Hardware malfunctions: when without service can not do
If all software methods have been tried, but the Redmi Note 8 Pro still doesn't charge fast, the problem is probably hardware.
- 🔋 Battery wear: bloating, capacity <80%, Solution: battery replacement (cost) ~2 000 ruble).
- 🔌 Damage. USB-port: charging only works in a certain position of the cable, data transmission is unstable (~1 500 rubles).
- 📱 Power controller malfunction: smartphone warms up, fast charging turns on for a few seconds and shuts down.Solution: Chip replacement MT6358 (~3,000 rubles).
- 🔄 Problems with the motherboard: charging is not going at all, the smartphone does not turn on. Solution: diagnostics in the service (repair from 4000 rubles).
- ⚡ Short circuit: Smartphone turns off when charging is connected, power supply heats up.Solution: full diagnosis (~1,000 rubles).
Note: if the smartphone is swollen (the body is deformed, the screen "steps away" from the frame) - immediately disconnect it from charging! This is a sign of critical battery wear, which can lead to fire.
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Before visiting the service, back up your data via Mi Cloud or your computer. After repairs (especially replacement fees), you may need to reset your settings completely.
The cost of repairs in informal services may be lower, but the risks are higher: often use non-original parts (for example, batteries without overheating protection). 20-30%.
8. Alternative methods of accelerating charging
Restore Quick Charge 3.0 It didn't work, but it's still charging (albeit slowly), and you can try to speed things up in alternative ways, which won't replace full-blown fast charging, but they do shorten the time by a little bit. 15-20%.
Methods of acceleration:
- ❄️ Refrigeration: Put your smartphone in a cool place (but not in the fridge!) at temperature 20-25°C charging goes to 10% faster.
- 📴 Air mode: disables communication modules (4G, Wi-Fi, Bluetooth, reducing the load on the processor. 5-15%.
- 🔕 Turn off all applications, especially instant messengers and social networks that are constantly synced.
- 🔋 Charging in the off state: without load from the OS, the battery is charged to 20-30% faster.
- 🔌 Power Delivery: If you have a power supply with USB-PD (For example, from a MacBook, it can give up to 15W instead of the standard 10W.
You can also try calibrating the battery (if the problem is incorrectly displaying the percentage of charge):
- Discharge the smartphone to 0% and wait for the automatic shutdown.
- Connect the original charger and charge for at least 8 hours (even if the indicator shows 100%).
- Turn off the charging, turn off the smartphone for 5 minutes, then turn it on.
These methods won’t bring back Quick Charge, but they will help reduce charging times in critical situations.