Your Xiaomi Redmi 8 started charging like a snail, even though it used to do it in an hour? That's not a sentence - in 90% of cases, the problem can be solved without repair. Slow charging on this smartphone arises from a combination of hardware and software factors, many of which users overlook. For example, a degraded battery after 500 charging cycles can reduce speed by 40%, and background processes can be reduced. MIUI — "steal up to 30% of the charger’s power.
In this article, we'll look at all the possible causes, from the banal contamination of the connector to the hidden power saving settings that are not even written about in official manuals. You'll learn how to return the original charging speed of 18 watts (or close to it), which accessories really work and which only steal your money. And most importantly, when to carry your phone to the service, and when to clean the contacts with a toothbrush.
1. Checking the charger and cable: 3 tests you haven't done
Start with the obvious, the power supply and the cable, and even if they look good, their real power could have dropped by 50 percent because of wear and tear, and here's how to check them correctly (not just "switch them around"):
First, use the Ampere app (available on Google Play), which shows the actual charging current in milliamps. Redmi 8's normal values are:
- 🔌 The original block 18W: 1800–2200 mA at 9V (fast charging)
- 🔌 Standard block 10W: 1000–1400 mA at 5V (slow charging)
- 🔌 Faulty block: below 800 mA or galloping values
If the numbers are below normal, the problem is in the block or cable.
Second, do a visual cable test:
- 🔍 Bend the cable at the base of the connector - if there are cracks or cracks, it's time to change it.
- 🔍 Light a flashlight in the USB-Type-C port of the phone: inside should not be dust, oxidation or bent contacts.
- 🔍 Try charging your phone from another device (e.g. power bank) – if the speed has increased, the power supply is to blame.
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Do not use cables longer than 1 meter long – they lose up to 20% of power due to resistance.
Third, check protocol compatibility.Redmi 8 Supports Quick Charge 3.0, But with original accessories, cheap Chinese blocks often pose as "fast" but actually work on the same thing. 5V/1A. Pay attention to the marking:
- ⚡ Supported standards: QC 3.0, QC 2.0, USB-PD (partly)
- ❌ Incompatible: Samsung AFC, Huawei SCP, "smart charging with auto-regulation
Type-C connector cleaning: why 70% of users do it wrong
A contaminated USB-Type-C connector is one of the main causes of slow charging, but most clean it in dangerous ways. Using metal objects (needles, paper clips) can damage or close the contacts, leading to a complete failure of charging.
How to clean the connector correctly and safely:
- 🧼 Use a soft bristle toothbrush soaked in isopropyl alcohol (not in water.
- 💨 To dry, use a dryer in cold mode (not hot!) or leave your phone for 30 minutes.
- 🔍 For hard-to-reach places, a wooden toothpick (not metal) is suitable!).
- 🚫 Never blow with your mouth – saliva contains acids that oxidize contacts.
If the speed has not increased after cleaning, check the physical condition of the connector:
- 🔍 Contacts should not be bent or oxidized (green/black coating).
- 🔍 The connector should not hang - this is a sign of a loose soldered joint.
- 🔍 When connecting the cable should not be sparks or heating.
What to do if the contacts are oxidized?
3. MIUI settings that slow charging (and how to turn them off)
Xiaomi Redmi 8 is working on the MIUI, This is a default setting that limits charging to extend battery life. These settings often remain on even after you reset your phone:
Open the Settings. → Battery and productivity → Battery settings and turn off:
- 🔋 "Optimized charging – limits current to 80% to protect the battery.
- 🔋 "Power saving mode - reduces the charging speed by 30-50%.
- 🔋 "Adaptive battery – artificially restricts background processes, but sometimes blocks charging.
Also check the hidden developer settings (if enabled):
- Go to Settings → About Phone → The MIUI version and tap it 7 times to activate the developer mode.
- Back to Settings → Additionally. → For developers.
- Find the item "Restriction of background activity" and set without restrictions.
- Turn off Optimization. MIUI" (may conflict with charging).
If the charge rate has increased after the changes, but the phone has warmed up - this is normal. Redmi 8 does not have active cooling, so when charging fast, heating to 40-45°C, but if the temperature is above 50.°C, immediately disconnect the phone from the network!
Deactivate "Optimized charging"|Check the energy saving mode|Deactivate "Adaptive battery"|Checking the developer's settings-->
4. Battery: How to tell if it's dead (even if the phone turns on)
The Lithium Polymer batteries in Redmi 8 are designed to last 500 to 800 charge cycles, and then their capacity drops by 20 to 30 percent. If your phone is older than 2 years, chances are that the battery has already degraded. Here's how to check this:
Download the AccuBattery app (free version is enough) and pay attention to:
- 📊 "Battery Health – If the value is below 80%, the battery needs to be changed.
- 📊 "Actual capacity — the new Redmi 8 has 5,000 mAh. If it shows 3,500-4000 mAh, the battery is worn out.
- 📊 "Charging temperature" - if above 45°C, it's a sign of degradation.
Also note the indirect signs of a “dying” battery:
- ⚡ The phone will run out in 3-4 hours with normal use.
- ⚡ Charging jumps (for example, from 50% Suddenly drops to 20%).
- ⚡ The phone turns off at 10-15% charge, although it used to work up to 1%.
- ⚡ The body is swelling (check if the phone is on the table).
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If the battery capacity is below 60 percent of the original capacity, no settings or firmware will return fast charging. ~1500–2500 ₽ service).
If you decide to change the battery yourself, be careful:
- 🔧 Use only the original battery (article: MB11 or MB12 for Redmi 8).
- 🔧 Don’t buy cheap ones – they may swell or not support fast charging.
- 🔧 Calibrate the battery after replacement: completely discharge the phone, then charge to 100% without interruptions.
5. Software failures: reset, firmware and hidden commands
Sometimes slow charging is caused by firmware failures or system process conflicts. If all the hardware checks are done and the problem persists, try these methods:
Soft reset (does not delete data, but resets energy settings):
- Go to Settings → System → Additional → Resetting settings.
- Select Network Reset and Energy Saving.
- Confirm the action and restart the phone.
Hard Reset is a last resort if a soft reset doesn't work. It will delete all the data, so back up first.
- Turn off the phone.
- Press the power button. + Volume up 10 seconds to enter Recovery Mode.
- Select Wipe Data → Wipe All Data (Change Volume Buttons).
- After resetting, the phone will restart in factory condition.
If the resets didn’t help, try updating the firmware:
- 📱 Go to Settings. → The phone. → Updating the system.
- 📱 If the update is available, install it. If not, download the latest version. MIUI For Redmi 8 from Xiaomi’s official website and manually run through Recovery.
For advanced users: check the status of the power controller through the engineering menu:
- Enter the code in the phone app: ##4636##
- Go to Battery Information.
- Check the parameters AC Power and USB If the values are below 1500 mA, the problem is in the controller.
What if the phone doesn’t see the charger at all?
External factors: temperature, humidity and “invisible” interference
The Redmi 8’s charging speed is heavily influenced by external conditions that users often ignore.
| Factor. | Impact on charging | How to fix it |
|---|---|---|
| Temperature below 10°C | Charging slows down or stops | Charge in a warm room (20–25)°C) |
| Temperatures above 45°C | The controller limits current to 50% | Let the phone cool down before charging |
| Humidity >60% | Risk of contact oxidation, slow charging | Use silica gel or dry with a hair dryer (cold air) |
| Magnetic fields (dynamics, columns) | Interference with the power controller | Keep your phone away from magnetic radiation sources |
| Using the phone while charging | Speed reduction by 30-50% | Do not run resource-intensive applications (games, videos) |
Charging in the cold is especially dangerous. Lithium-ion batteries at temperatures below 0°C can lose capacity irreversibly. If you had to charge your phone outside in the winter, let it heat up to room temperature before you connect to the grid.
Another hidden enemy is wireless charging. Redmi 8 doesn't officially support Qi, but some users try to charge it through adapters. 5W), Uncertified adapters can damage the power controller.
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If you charge your phone at night, put it on a non-combustible surface (like ceramic tiles) to prevent overheating and possible fire if the battery fails.
7.When to contact the service: 5 signs of a serious breakdown
If you've tried all the methods, but the Redmi 8 is still charging slowly, perhaps the problem is deeper than it seems.
- ⚠️ The phone does not charge at all, even after cleaning the connector and changing the cable.
- ⚠️ When connected to charging, the phone turns off or restarts.
- ⚠️ The battery swelled (see by the curvature of the screen or back cover).
- ⚠️ Charging is only in the off state.
- ⚠️ The phone is very hot (over 50).°C) even when slowly charged.
The service center should check:
- 🔧 Power controller (frequent problem after falls or moisture ingestion).
- 🔧 Integrity of tracks on the motherboard (can burn out when voltage surges).
- 🔧 USB-Type-C connector status (sometimes need replacement).
- 🔧 Battery controller firmware (sometimes gets knocked down after updates).
The cost of repair in official Xiaomi services:
- 💰 Replacement of connector: 800-1500 ₽
- 💰 Replacement of the power controller: 2000–3500 ₽
- 💰 Diagnostics + firmware: 500-1000 ₽
- 💰 Battery replacement: 1500–2500 ₽ (work)
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If the phone is warranty-free, don’t try to repair it yourself! opening the case or replacing components will void the Xiaomi warranty.
How to choose a service center:
- 🔍 Check if the center has a certificate from Xiaomi (list of official partners on the website mi.com).
- 🔍 Read reviews on Yandex.Maps or 2GIS – especially pay attention to complaints about batteries.
- 🔍 Check if you have a warranty for repairs (should be at least 3 months).
- 🔍 Ask to show original parts before replacing (they must have Xiaomi logo and hologram on them).