5 Signs Your iPhone Battery Needs Replacing

Not sure if it's the battery or the phone? These are the warning signs we look for, and what to do about each one.

By Mike, Bristol iPhone Repair, repairing iPhones since 2007

Every iPhone battery wears out eventually. Each time you charge it, the battery loses a tiny bit of the charge it can hold. Two or three years in, most people notice their iPhone doesn't last like it used to. Knowing when a tired battery has become one that needs replacing is the tricky part.

These are the five signs we come across most often when customers call us out.

1. Your iPhone battery runs out much sooner than it used to

This is usually the first thing people notice. Your iPhone once got you to bedtime with charge to spare. Now you're hunting for a charger by mid-afternoon. That's a battery losing capacity.

You can check it in a few seconds. Go to Settings → Battery → Battery Health & Charging and look at Maximum Capacity. When it drops below 80%, Apple says the battery is due for replacement. You may also see a "Service" message on that screen.

2. It switches off with battery still left

Your iPhone says 25%, then the screen goes black and it won't come back on until you plug it in. A worn battery can't deliver enough power at lower charge levels, so the phone shuts down to protect itself. It's often worse on cold days, which is why winter is when a lot of tired batteries finally give up.

Your iPhone may also start to feel sluggish. After an unexpected shutdown, iOS can slow the phone down to stop it happening again. A new battery removes that slowdown.

3. The battery percentage jumps around

If your iPhone goes from 50% to 18% in a few minutes, or leaps up the moment you plug it in, the battery can't report its charge accurately any more. You can't trust the number on screen, so you never know how long you've really got.

4. Your iPhone gets hot doing everyday things

Any iPhone warms up during gaming, video calls or a long navigation trip. If it feels warm while you're just scrolling or texting, something's working harder than it should. A failing battery is a common cause, but an app or software problem can do the same thing. We test the battery health before suggesting a replacement.

5. The screen is lifting or the back is bulging

This one needs dealing with straight away. When a lithium battery breaks down it can produce gas and swell up. Inside an iPhone that pushes the screen away from the frame. You might see a gap down one side, or the phone may rock when you lay it flat.

What to do if your iPhone battery needs replacing

The good news is that an iPhone battery replacement is one of the quickest, cheapest repairs there is, and it can make an older iPhone feel new again. At Bristol iPhone Repair, battery replacements start from £59. If we're already replacing your screen, the battery is just £25 extra.

We're a fully mobile service. We drive to your home or workplace anywhere in Bristol and the surrounding areas, and fit your new battery in our repair van while you wait. Every battery comes with a 12-month warranty, and if we can't fix it, you don't pay.

Want your current battery to last longer in the meantime? Have a read of our guide on how to extend your battery life.

Frequently asked questions

How long does an iPhone battery last?

Most iPhone batteries start to noticeably fade after two to three years, depending on how heavily the phone is used and how often it's charged.

How long does an iPhone battery replacement take?

Usually well under an hour. We do it on the spot in our van, so you don't have to be without your phone.

Will I lose my data?

No. A battery replacement doesn't touch your data. It's always sensible to have an up-to-date iCloud backup before any repair, just in case.