Why Is My Phone Wireless Charging Slowly?

Problem Summary

Wireless charging feels slow. Your phone takes hours longer than expected to charge, or the battery percentage barely moves during a charging session.

The most common cause: An underpowered USB adapter bottlenecking the wireless charger.

8 Causes of Slow Wireless Charging

1. Underpowered USB Adapter

This is the single most frequent cause. Every wireless charger requires an external power adapter. Many chargers ship without one.

If your 15W wireless charger is plugged into the phone charger that came with an older device — especially one rated 5W or 10W — the wireless pad cannot deliver more than that adapter provides.

Fix: Use a USB-C Power Delivery (PD) adapter rated 25W or higher. Budget options from reputable brands cost $10-15.

2. Poor Coil Alignment

The transmitter coil in your charging pad and the receiver coil in your phone must overlap to transfer power efficiently. Even 1cm of misalignment can reduce charging speed by 20-40%.

Fix: Reposition the phone so it is exactly centred on the pad. Many pads have a small indicator or centre mark. Some phones vibrate when properly aligned.

3. Thick or Metal Phone Case

Cases work with wireless charging in most situations. Exceptions:

• Cases thicker than approximately 3mm
• Cases with metal plates (common in wallet cases with card slots)
• Cases with RFID-blocking material
• Cases with embedded magnets positioned over the charging coil

Fix: Try charging without the case. If speed improves, consider a thinner case or one specifically labelled wireless charging compatible.

4. Phone Overheating

When a phone battery reaches high temperatures (typically above 40-45C), the device automatically reduces charging speed to protect the battery. This is normal and intentional.

Fix: Move the phone to a cooler location. Remove it from direct sunlight. Avoid using the phone intensively while wirelessly charging, as processor load generates heat.

5. Low-Quality Charger

Not all wireless chargers that claim 15W actually deliver 15W. Uncertified chargers may over-claim their wattage. A charger without Qi or Qi2 certification has not been tested for interoperability.

Fix: Check for the Qi or Qi2 certification logo on the charger packaging. Certified chargers are guaranteed to meet their rated specifications.

6. Battery Protection Mode Active

Most modern Android phones include battery protection or adaptive charging features that limit the charging rate, particularly when the battery is above 80% or the phone is on the charger for an extended period.

Fix: Check Settings > Battery > Battery Protection (Samsung) or similar setting. Disable temporarily if you need a full fast charge.

7. Background Processes Consuming Power

If your phone is running intensive background processes — large app updates, video transcoding, GPS navigation — the phone may be consuming power faster than the wireless charger can supply it, resulting in either no net charge gain or very slow progress.

Fix: Put the phone in aeroplane mode or close background apps while charging.

8. Worn or Damaged Charging Pad

Wireless charger coils can degrade over time, particularly with physical damage or prolonged heat exposure. An old charger may no longer deliver its rated wattage reliably.

Fix: Test with a different wireless charger. If the problem is resolved, replace the original pad.

When to Replace Your Charger

Replace your wireless charger if:

• It delivers noticeably less power than when new
• The indicator light behaves erratically
• The pad gets unusually hot (more than warm)
• Testing with a known-good charger resolves your speed issue

Use the Charging Calculator

Want to know what speed to expect with your specific setup? Use the Charging Time Calculator to calculate expected charging time based on battery size, wattage, and efficiency.

Related Pages

• Why does my phone get hot while wireless charging?
• Do phone cases affect wireless charging?
• Wireless charging wattage guide
• How to fix wireless charging not working