iPhone battery draining fast? What to check
10 November 2026 · Mac guides
If your iPhone used to last all day and now needs charging by mid-afternoon, the battery is not always the culprit. An app stuck in the background, a recent update or the cold can all drain it faster than usual. This guide walks through the checks worth doing at home, how to read your battery's health, and when a new battery is the sensible fix.
First, look at what is using the power
Open Settings > Battery. The chart shows your battery level over the last 24 hours and the last 10 days, and the list underneath shows which apps used the most power. Tap an app's entry to see how much of that was on screen and how much was in the background.
Things to look out for:
- One app using far more than the others, especially in the background. Close it, check the App Store for an update, and if it keeps happening, delete and reinstall it.
- A steep drop overnight while the phone was not being used. That usually points to something running in the background, such as a sync, a backup or an app using your location.
- Weak signal or "No Service" in the list. Your phone works harder when the mobile signal is poor, so a basement flat or office with bad reception can drain the battery noticeably.
Just updated iOS? Give it a couple of days
After a major iOS update, your iPhone does a lot of work behind the scenes, such as re-indexing photos, messages and files. During that time the battery can drain faster and the phone may feel warm. This normally settles down by itself within a day or two, so it is worth waiting before deciding the battery has gone. Keep the phone on charge overnight on Wi-Fi to help it finish.
Cold weather makes batteries look worse
Lithium-ion batteries do not like the cold. Apple says iPhones work best at ambient temperatures between 0 and 35°C. On a cold winter's day outdoors, an older battery can drop sharply or the phone can even switch off with charge still showing. That loss is usually temporary and the charge comes back once the phone warms up. If the drain only happens outside in the cold, the battery may simply be ageing rather than faulty.
Settings that genuinely help
- Low Power Mode (Settings > Battery) cuts back background activity and visual effects. It is a good stopgap on a long day.
- Background App Refresh (Settings > General > Background App Refresh) can be turned off for apps that do not need to update while you are not using them.
- Location Services (Settings > Privacy & Security > Location Services): set apps to "While Using" or "Never" unless they really need your location all the time.
- Screen brightness: the display is one of the biggest power users. Auto-Brightness and a slightly lower level make a real difference.
A simple restart is also worth trying. It clears out processes that have got stuck, which is sometimes all it takes.
How to check your battery's health
Go to Settings > Battery > Battery Health (called Battery Health & Charging on some versions of iOS). You will see a Maximum Capacity figure, which compares your battery now with when it was new.
Apple says batteries in iPhone 14 and earlier models are designed to keep up to 80% of their original capacity at 500 full charge cycles, and those in iPhone 15 and later models up to 80% at 1,000 cycles. On iPhone 15 and later you can also see the cycle count in Settings, under General > About or in Battery Health, depending on your iOS version.
As a rough guide:
- Above 80%: the battery itself is probably fine, and the drain is more likely to be an app, a setting or signal.
- Around 80% or below: you will notice shorter battery life, and a replacement starts to make sense.
- A "Service" message in Battery Health means iOS has detected that the battery is significantly worn. Apple recommends having it serviced.
- A note about peak performance means your iPhone has shut down unexpectedly and is now slowing itself slightly to stop it happening again. A new battery normally removes that limit.
If you see a message saying the battery cannot be verified as a genuine Apple part, the battery has probably been replaced at some point with a non-Apple part.
Signs it is more than a tired battery
Some symptoms are not caused by normal wear and need a closer look:
- The screen lifting or the back bulging. This can be a swollen battery. Stop using and charging the phone, do not press on it, and get it checked.
- The phone getting hot when idle or while charging, even with nothing open.
- Shutting down at 20% or 30%, or the percentage jumping around.
- Not charging at all, or only charging with the cable held at an angle. This is more often the charging port, which can fill with pocket fluff, than the battery itself.
- Drain that started after a drop or a spill. Damage to the phone's board can cause power to leak away even when the phone is asleep.
Repair or replace the phone?
A new battery is one of the simplest ways to give an iPhone a longer life. If the phone otherwise works well, is still getting iOS updates and you are happy with it, replacing the battery is usually far more sensible than buying a new phone, especially at a time when new devices are expensive. If the phone has several other faults, such as a cracked screen, a failing camera and a worn battery all at once, or it no longer receives updates, it may be time to compare that with replacing the phone.
You can read more about the faults we look at on our iPhone repairs page.
Keep your photos and messages safe first
Before any repair, back up your iPhone. Check that iCloud Backup has run recently (Settings > your name > iCloud > iCloud Backup) or back it up to a Mac or PC. A battery replacement should not affect your data, but a backup means nothing is lost if anything unexpected turns up. If the phone is swollen or getting hot, back up only if you can do it quickly and safely, then stop using it.
Get a quote
Call 020 7394 2525, or bring your iPhone to 80 Willow Walk, London SE1 5SY. We are open 9am to 6pm, Monday to Saturday, with bike collection in London and courier collection across the UK. You can also send us a message.