Phone battery draining fast

Find out what is using the power before changing settings at random. The battery screen names the culprit.

What you seeThe battery falls 20 to 30 per cent in an hour of light use, or drains overnight

1. Read the battery screen

• Android: Settings › Battery › Battery usage. It shows use since the last full charge, by app and by system.
• iPhone: Settings › Battery. Tap "Show Activity" to see time on screen and in the background for each app, over the last 24 hours or 10 days.

Look for:

• An app high on the list that you barely used. It is running in the background. See step 3.
• Screen at the top: normal. The display is the biggest consumer; see step 4.
• Mobile network or "No service" high up: weak signal makes the radio work at full power. See step 5.
• A drain that began on a particular day: think of what you installed or updated then.

2. The quick fixes

1. Restart the phone. A stuck process can drain a battery in hours.
2. Update the system and apps. Drain bugs are common after updates and are usually fixed in the next one.
3. Just after a big system update, heavy drain for a day or two is normal while the phone re-indexes. Wait before worrying.

3. Tame background apps

• Android: Settings › Apps › the app › App battery usage › choose Restricted for apps that have no need to run in the background (games, shopping apps). Do not restrict messaging, email or alarm apps, or their notifications will be late. See notifications not coming.
• iPhone: Settings › General › Background App Refresh: turn it off for apps that need not update unseen.
• Uninstall apps you do not use.
• Location: Android Settings › Location › App location permissions; iPhone Settings › Privacy & Security › Location Services. Change "Always" (Android: "Allow all the time") to "While Using" for everything except navigation and safety apps.

4. The screen

• Lower the brightness, or leave adaptive (auto) brightness on.
• Shorten the screen timeout to 30 seconds or a minute: Android Settings › Display › Screen timeout; iPhone Settings › Display & Brightness › Auto-Lock.
• Use dark mode on phones with OLED screens, where black pixels use almost no power.
• Turn off Always-on display if you do not need it.
• On phones with 90 or 120 Hz screens, choosing the standard 60 Hz setting saves a noticeable amount.

5. Signal and radios

• In a weak-signal area (basements, trains, villages), the phone hunts for signal constantly. Use Wi-Fi where you can, or flight mode when you do not need calls.
• On a 5G phone where 5G is patchy, setting the preferred network to 4G/LTE can help: Android Settings › Network & internet › SIMs › Preferred network type; iPhone Settings › Mobile Service › Mobile Data Options › Voice & Data.
• Hotspot drains fast; switch it off after use.
• Leaving Bluetooth and Wi-Fi on costs very little. There is no need to toggle them all day.

6. Use the power-saving mode

• Android: Settings › Battery › Battery Saver (Samsung: Power saving). Set it to turn on by itself at 20 or 30 per cent.
• iPhone: Settings › Battery › Low Power Mode.

These limit background work, visual effects and screen refresh.

7. Is the battery worn out?

Batteries are consumable. After two to three years of daily charging, capacity falls noticeably.

• iPhone: Settings › Battery › Battery Health & Charging › Maximum Capacity. Below 80 per cent, a replacement is worth it.
• Android: some phones show it under Settings › Battery › Battery health or Settings › About phone › Battery information, or in the maker's support app (Samsung Members › Support › Phone diagnostics).

Signs of a failing battery: the percentage drops in jumps, the phone switches off at 20 or 30 per cent, it runs hot while idle, or the back is bulging. A swollen battery is dangerous: stop charging and using the phone and take it to a service centre.

Charging habits that help the battery last

Avoid heat above all: do not charge under a pillow or on a car dashboard. Use the optimised or adaptive charging setting (Android: Settings › Battery › Adaptive charging or "Protect battery"; iPhone: Battery Health & Charging › Optimised Battery Charging, and the 80% limit on recent models). Topping up through the day is fine; you need not run the battery flat.

For Android phones and iPhones. Written in November 2026 for Android 13 to 15 and iOS 17 and 18. Phone makers rename menus; use the search box in Settings if a name differs. Back up before any reset. This is an independent guide, not connected with Google, Apple, Samsung or any phone maker or operator.