Huawei Mate 8 Charges Slowly? Fix It Fast
If your Huawei Mate 8 is charging slowly, the most likely fix is to replace the charging cable and use a charger that supports fast charging (9V/2A). A faulty USB cable or a low-power adapter are the top causes, and both are easy to check and swap out.
Why Your Mate 8 Charges Slowly
The Huawei Mate 8 supports Huawei’s Fast Charge protocol, which delivers up to 18W (9V/2A). When everything works correctly, a full charge takes about 1.5–2 hours. If it’s taking much longer, something in the charging chain is limiting the power. The chain includes the wall adapter, the USB cable, the phone’s charging port, and the battery/software.
Most slow charging cases come down to one of these:
- Using a charger that outputs only 5V/1A or 5V/2A – common with old phone chargers or third-party adapters that don’t support fast charging.
- A damaged or low-quality USB cable – cables wear out internally, and many cheap cables only support slow charging.
- Dust or lint in the charging port – blocks proper contact and reduces current flow.
- Software or battery issues – after years of use, the battery may degrade, or a background app may be draining power while charging.
How Fast Charging Works on the Mate 8
The Mate 8 uses a higher voltage (9V) and lower current (2A) to push more power into the battery safely. The phone’s charging IC negotiates with the charger over the USB data lines to agree on the voltage. If the charger doesn’t support this negotiation, the phone falls back to standard 5V charging, which is much slower.
You can see the charging status on the lock screen. It may show “Fast charging” or just “Charging”. If it doesn’t say fast charging, the phone is not getting the higher voltage.
Step-by-Step Fixes to Try
- Use the original charger and cable – If you have them, plug them in and see if the phone shows fast charging.
- Try a different USB cable – Even if the cable looks fine, it may be broken inside. Borrow a cable from another fast-charging phone and test.
- Clean the charging port – Turn off the phone, use a wooden toothpick or a soft brush to gently remove lint. Do not use metal tools.
- Check the wall outlet – Some outlets or power strips may not deliver full current. Try a different socket.
- Restart the phone – A simple reboot can clear software glitches that affect charging speed.
- Check battery usage – If an app is using a lot of power while charging, the net charge rate drops. Close heavy apps or turn on Airplane mode.
- Replace the battery – If the phone is several years old and the battery drains quickly even after a full charge, the battery may need replacement.
Choosing the Right Charger and Cable
To get fast charging, you need a charger that supports 9V/2A output. Many third-party chargers from reputable brands support this, but some only output 5V. Look for “9V/2A” or “Quick Charge 2.0/3.0” on the label – the Mate 8 is compatible with Qualcomm Quick Charge 2.0, so those chargers work.
The cable also matters. A cable that is too thin or has high resistance will limit current. Use a cable that is rated for at least 2A. Original Huawei cables are best, but quality third-party cables with proper certification also work.
Common Misconceptions
“Charging overnight damages the battery.” The Mate 8 has overcharge protection, so leaving it plugged in overnight is safe. However, keeping the battery at 100% for long periods can accelerate aging slightly, but it’s not a safety risk.
“Using a higher wattage charger will charge faster.” The phone only draws what it’s designed to. A 40W charger will still charge at 18W max. It won’t damage the phone, but it won’t speed things up either.
“Wireless charging works on the Mate 8.” The Mate 8 does not support wireless charging. You must use a cable.
When to Consider a Battery Replacement
If you’ve tried new cables and chargers, cleaned the port, and the phone still charges slowly, the battery may be degraded. Lithium-ion batteries lose capacity over time. A battery that’s worn out will charge slower and drain faster. If the phone also shuts down unexpectedly or the battery percentage jumps around, replacement is likely needed. A professional repair shop can replace the battery, which usually restores normal charging speed.
Frequently Asked Questions
Why does my Mate 8 say “charging” but not “fast charging”?
This means the phone is not getting the 9V/2A signal. The charger or cable doesn’t support fast charging, or the port isn’t making good contact. Try a different cable and charger that support 9V/2A.
Can I use a Quick Charge 3.0 charger?
Yes, Quick Charge 3.0 chargers are backward compatible with Quick Charge 2.0, so they will charge the Mate 8 at full speed.
Is it safe to use the phone while charging?
Yes, but it may slow down charging because the phone uses some power to run. If you need the fastest charge, leave the screen off and close background apps.
How long should a full charge take?
With a proper 9V/2A charger, about 1.5 to 2 hours from empty to full. If it takes longer than 3 hours, something is wrong.
Why does my phone charge slowly when the screen is on?
The screen and processor use power, so the net charging rate drops. The phone may also reduce charging current to prevent overheating when the screen is on.
Can a bad cable damage the phone?
It’s unlikely to damage the phone, but a bad cable can cause slow charging or intermittent charging. In rare cases, a very poor quality cable could overheat, so it’s best to use a certified one.
Related
Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.