Fast charging is one of the biggest advantages of the Xiaomi 15 Ultra, so when it suddenly stops working, charging feels painfully slow. You plug the phone in, but the fast charging label never appears, and the battery percentage barely moves. In most cases, this issue is caused by settings, accessories, or power-related limitations, and you can fix it without going to a service center.
Why Your Xiaomi 15 Ultra Fast Charging Is Not Working
- The charger or cable does not support fast charging.
- Battery protection or optimization features are limiting charging speed.
- Dirt or debris is blocking the charging port.
- The phone is overheating while charging.
- Software glitches after a system update.
1. Check the Charger and Cable
Fast charging only works when both the adapter and cable support the required wattage. Using an older charger or a low-quality cable will force the phone to charge at normal speeds.
Unplug the charger, and then inspect the cable for damage.
Plug in the original Xiaomi charger, and then connect it directly to a wall outlet.
Lock the screen and wait a few seconds to see if the fast charging message appears.
2. Disable Battery Protection Features
Xiaomi phones include battery protection settings that slow down charging to extend battery lifespan. When enabled, these features can prevent fast charging even if the charger supports it.
Open Settings, and then tap Battery.
Tap Battery protection or Charging protection, and then turn it off.
Reconnect the charger and check if charging speed improves.
3. Let the Phone Cool Down
Fast charging automatically slows down when the phone gets too warm. This is a safety measure to protect the battery and internal components.
Disconnect the charger, and then remove the phone case.
Wait a few minutes for the device to cool down, and then plug the charger back in.
Avoid using the phone heavily while charging.
4. Clean the Charging Port
Dust and lint inside the charging port can interfere with power delivery. Even a small blockage can prevent fast charging from activating.
Turn off the phone, and then inspect the charging port under good lighting.
Gently remove debris using a wooden toothpick or compressed air.
Plug the charger back in and test fast charging again.
5. Restart the Phone
Temporary software glitches can affect charging behavior. Restarting the phone refreshes background services and often restores fast charging.
Press and hold the Power key, and then tap Restart.
Wait for the phone to fully boot up, and then connect the charger.
Check the lock screen for the fast charging indicator.
6. Update the System Software
Charging issues can sometimes be caused by bugs that are fixed in later updates. Keeping your phone updated ensures compatibility with fast charging protocols.
Open Settings, and then tap About phone.
Tap System update, and then install any available updates.
Restart the phone after updating and test fast charging again.
Fast charging on the Xiaomi 15 Ultra is reliable when everything is working correctly. Once you rule out accessory issues and remove charging limitations, your phone should return to charging at full speed.
FAQs
Why does my Xiaomi 15 Ultra say charging but not fast charging?
This usually means the charger or cable does not meet the required power output. Using the original Xiaomi adapter and cable fixes this in most cases.
Does using the phone while charging disable fast charging?
Yes, heavy usage can generate heat, which causes the phone to slow down charging. Letting the phone rest while charging helps maintain fast speeds.
Can fast charging damage the battery over time?
Fast charging is designed to be safe, but battery protection features exist to reduce long-term wear. Using fast charging occasionally will not harm the battery under normal conditions.
