7 Signs Your Phone Battery Needs Replacing

Every phone battery is a lithium-ion cell that slowly loses capacity each time it’s charged and drained. After a couple of years of daily use, it’s normal for a phone that once lasted all day to struggle to make it to the afternoon. Here’s how to tell when it’s time for a new one.

1. It drains much faster than it used to

If you’re charging twice a day when you used to charge once, and you haven’t changed how you use your phone, the battery has probably lost a good chunk of its capacity.

2. It shuts down with charge left

A worn battery can’t always deliver the power the phone asks for, especially in the cold or when the camera or a game is running. The result: the phone suddenly turns off at 15%, 20% or even higher, then shows a higher percentage once it’s plugged back in.

3. Battery Health says so

On iPhone, go to Settings → Battery → Battery Health (called Battery Health & Charging on some versions). Apple says batteries in most models are designed to keep about 80% of their original capacity at 500 full charge cycles, and iPhone 15 and later models at 1,000 cycles. If Maximum Capacity is around 80% or lower — or you see a “Service” message — replacement is worth considering.

On Android, it depends on the brand. Some newer phones show battery health in Settings → Battery, and Samsung phones can run a battery check in the Samsung Members app under Diagnostics.

4. The phone feels slow

Some phones reduce peak performance to avoid unexpected shutdowns when the battery is worn. If apps open slowly and everything feels sluggish, an ageing battery can be part of the reason.

5. It gets hot during normal use

A little warmth while charging or gaming is normal. A phone that runs hot while doing very little can point to a battery (or charging) problem worth checking.

6. The percentage jumps around

Dropping from 40% to 10% in a few minutes, or jumping up the moment you plug in, suggests the battery can no longer hold a steady charge.

7. The battery is swelling — stop using it

A swollen battery can push the screen up, open a gap along the edge or make the back of the phone bulge. If you see this, stop charging the phone, don’t press on it or try to open it, keep it away from heat, and bring it in to be looked at as soon as possible.

How to make a battery last longer

• Avoid heat. Don’t leave your phone in a hot car or charge it under your pillow.
• Use optimized charging. iPhone and many Android phones can hold the charge at 80% overnight and finish just before you wake up.
• Don’t run it to 0% all the time. Lithium-ion batteries are happiest in the middle of their range.
• Use a decent charger and cable. Poor-quality chargers can deliver unstable power. Browse our chargers and cables.

Not sure it’s the battery?

Sometimes a phone that won’t charge properly actually has a dirty or damaged charging port. If you’re unsure, describe what’s happening in a quote request and we’ll help you figure it out.