Phone battery losing charge while plugged in? Here’s why, and simple fixes to try first

You plug in your phone at 18 per cent. Twenty minutes later, you check the screen and somehow it's at 15 per cent.

The cable is connected. The little charging symbol is there. So why is your battery going down?

It sounds like something is wrong with your phone, but in many cases, it isn't.

Charging is essentially a tug-of-war. Your charger is putting power into the phone while the screen, apps, processor, GPS and other features are using power at the same time. If your phone is using power faster than the charger can supply it, the battery percentage can keep falling even while it's plugged in.

The good news: The problem is usually something fairly simple: what you're doing on your phone, what you've plugged it into, how hot the phone is, the condition of the charging port or cable, or a software glitch.

So, before you blame the phone, charger or cable, there are a few simple things worth checking. We looked at manufacturer guidance from Apple, battery research and charging experts to find the most likely causes and the fixes you can try first.

This is one of the simplest explanations.

If you're playing a graphics-heavy game, watching videos, using Google Maps for navigation or running a mobile hotspot while charging, your phone is working hard while it's trying to refill its battery.

The screen is also one of the biggest drains, particularly at high brightness.

So if you're sitting in the car with Google Maps open, the screen at full brightness, Bluetooth connected and a video playing while your phone is plugged into a relatively weak car USB port, the battery can still lose ground.

Try this:

Sometimes the fastest way to charge your phone is simply to stop using it for 20 minutes.

A wall charger can generally deliver considerably more power than the USB port on an older laptop, hotel bedside table or car. That's why your phone may charge normally at home but barely move when you're plugged into your laptop.

The cable can also be the problem. A worn, damaged or poor-quality cable may charge much more slowly than a good one.

You don't necessarily need the phone manufacturer's charger, either. What matters is using a reputable charger that's compatible with your phone's charging requirements.

Try this:

If the battery starts climbing normally after changing the cable or charger, you've probably found your culprit.

Phones don't particularly enjoy being hot, and charging generates some heat of its own.

Add a bright screen, demanding apps, direct sunlight, a hot car or a thick case, and your phone can get warm enough to slow or temporarily stop charging.

This is deliberate. Phones have built-in protections that can reduce or pause charging when temperatures get too high.

That's why you might see your battery percentage sitting still rather than climbing, or even dropping if you're continuing to use the phone.

Wireless charging can also generate more heat than wired charging, particularly if the phone isn't sitting correctly on the charging pad.

Try this:

Your phone spends a lot of time in pockets, handbags and backpacks. That means charging ports can collect an impressive amount of lint and dust.

Over time, that debris can get compressed inside the port and prevent the cable from sitting properly.

You might notice that the plug feels loose, charging cuts in and out when you move the phone, or the cable only seems to work when it's held at a particular angle.

Try this:

Turn the phone off and inspect the port with a light.

If you can see lint or debris, preferably go to a service centre and have it removed, before trying to clean it on your own.

If the port looks clean but the cable still feels loose or charging keeps cutting out, the port itself may need attention.

Sometimes your phone can get stuck doing something in the background.

An app might be repeatedly refreshing, using your location or otherwise keeping the processor busy. The phone may feel warm even when you're not using it, and the battery may drain unusually quickly.

You don't need to panic and close every app you've opened. Modern phones are designed to manage background apps themselves, and constantly force-closing everything isn't necessarily helpful.

Instead, look for the app that's actually using the battery.

Try this:

If one app suddenly appears at the top of your battery list despite barely using it, it may be worth investigating.

There's another possibility: The battery percentage has stopped increasing because your phone is deliberately limiting charging.

Many newer phones have battery-protection features designed to reduce long-term battery wear. You may notice your phone stopping around 80% and holding there, particularly if it's charging overnight.

On iPhones, Optimized Battery Charging can delay charging beyond 80% until closer to when you normally unplug the phone. iPhone 15 and later models can also use a fixed Charge Limit between 80% and 100%.

Many Android phones have similar battery-protection or adaptive-charging features.

So if your phone sits at 80% for a while, that doesn't necessarily mean anything is wrong.

If your phone is losing battery while plugged in, try these fixes first:

Battery drops while you're gaming, streaming or navigating
Your phone is using power faster than the charger can supply it. Lock the phone, lower the brightness or switch on Battery Saver.

Battery barely moves when plugged into a laptop or car
The power source may be too weak. Try a wall charger or a proper car charger instead.

Your phone charges normally with one cable but slowly with another
The cable could be damaged or simply not capable of faster charging. Try a different cable.

The phone feels hot and charging has slowed or stopped
The phone may have activated its temperature protection. Stop using it, remove the case and let it cool down.

Wireless charging is slow or keeps stopping
Heat or poor alignment can interfere with charging. Reposition the phone on the pad or switch to a cable.

The cable feels loose or charging cuts in and out
Lint or dust may be packed into the charging port. Turn the phone off and gently clean the port with a dry, soft brush or wooden toothpick.

The phone feels warm and loses battery even when you're not using it
An app or background process could be consuming too much power. Check Settings > Battery, then restart the phone.

The battery stops around 80% and stays there
A battery-protection feature may be limiting the charge. Check your charging or battery settings before assuming something is wrong.

The battery drains quickly whether you're using the phone or not
The battery itself may be ageing. Check your phone's battery health and consider getting it serviced if its capacity is significantly reduced.