The one overlooked reason why your phone will not charge at full speed

The one overlooked reason why your phone will not charge at full speed

Fast charging is an equally complex and fascinating technology that allows phones to draw much higher levels of power for quicker battery top-ups. What many people don’t realize is that it relies on constant communication between the phone and the charger, and when that communication breaks down, charging falls back to much slower speeds.

So if your phone no longer fast-charges as it used to or no longer shows a fast-charging notification when using its original charge, there’s a common culprit that often takes just a minute to fix.

Lint and debris can stop fast charging

Your phone’s USB-C charging port uses multiple pins to deliver power and communicate with the charger. If dirt, wear, or damage interferes with those delicate contacts—especially the pins responsible for charging negotiation—your phone may stop fast charging and fall back to a much slower default charging mode.

In most cases, that means charging at 5V, which tops out at around 15W (5V at 3A) in the best-case scenario. That’s essentially the same speed you’d get from a basic, non-fast-charging cable and charger.

Over time, your phone’s USB-C port naturally accumulates dust and grime. Unless you use ananti-dust plug, there’s very little you can do to completely prevent that buildup.

Unfortunately, dust is usually just the beginning. Since most of us carry our phones in jacket or jeans pockets, pocket lint can easily work its way into the port, causing charging and data transfer issues.

This buildup can happen surprisingly fast—especially if you keep your phone in your pocket with the USB port facing down—meaning even a phone that’s less than a year old can end up with a significant amount of lint inside its USB-C port.

How to tell if your phone's USB port is dirty

A telltale sign of a dirty USB-C port is that plugging in the cable feels unusually difficult, and you don’t feel it click into place. When unplugging it, the cable may feel loose—almost like nothing is holding it in, and it wants to slip out on its own.

That’s usually a sign there’s so much debris inside the port that the small retention hooks on the USB-C connector can’t latch on properly.

In some cases, you may be able to spot dirt inside the port using a flashlight, but that’s usually only possible when the buildup is substantial. Even if the port looks clean on the surface, that doesn’t mean debris isn’t the problem.

Sticky dirt can collect directly on the pins themselves, where it’s difficult to see with the naked eye or even with a decent macro lens, but it'll still cause charging slowdowns.

The first time I ran into this issue was back in 2017, when my wife (then girlfriend) bought a used Huawei P9 Plus. The phone supported 18W fast charging, but no matter which charger we tried, it refused to charge above 5W (1A). This turned what would be a roughly one-hour charge until full into an overnight ordeal.

While troubleshooting, I noticed the charging cable felt unusually loose—especially compared to my micro-USB phone at the time. I carefully loosened and removed the packed-in debris using a threading needle (don’t do this; it’s easy to damage the port), and just like that, fast charging was back.

Since then, whenever I’ve run into fast-charging issues on my phones, cleaning the USB-C port has been the first thing I try—and so far, it’s worked every time. I’ve just retired the threading needle in favor of safer methods.

How to clean your phone's USB port without damaging it

The easiest and safest way to clean your phone’s USB-C port is withcompressed air. Hold the nozzle near the port and use short bursts to blow out loose dirt. If you don’t have a can handy, you could try blowing on the port yourself, but unless you have lungs of steel, it probably won’t do much.

After using the compressed air, inspect the port to see if any debris remains. If you still see lint stuck inside, you can gently remove it with a smallsoft-bristle brush designed for electronics. A fine interdental brush can also work in a pinch.

The key is to push the debris toward the corners and out of the port as gently as possible. Avoid putting any pressure on the middle section, as that's where the pins are located.

If the port still isn’t allowing fast charging, you can try electronics contact cleaner or isopropyl alcohol. Apply a tiny amount to the brush and gently clean the pins on both sides of the contact plate. This can dissolve sticky residue without damaging the port. You can even use a spare USB-C cable and plug it in and back out several times to "brush" the pins without damaging them.

If your phone still won't fast charge, the USB port might be damaged

If you've done your best job at cleaning the port, butfast charging still doesn't work, the USB-C port itself may be damaged. The port is constantly exposed to physical stress caused by repeated unplugging and plugging, as well as moisture that can corrode the pins.

However, before you jump to that conclusion, make sure to rule out the charger and cable by trying a different compatible fast charger and cable.

If that doesn’t help, you might want to consider replacing the USB-C port. Fast charging isn’t just about convenience—on phones with large batteries and ultra-fast charging speeds, like theOnePlus 15, it’s acore feature. You shouldn’t miss out on it just because the port is faulty.

The good news is that replacing a USB-C port is generally one of the cheaper and simpler smartphone repairs. Most ports sit on a “daughter board,” a small standalone component that’s relatively affordable and straightforward to replace.

That said, the repair still involves removing the back cover, which isn't something you should attempt yourself if you don't want to risk breaking it. So, take it to a professional and have them repair it for you.