Your phone lasted all day last month and now it is begging for a charger by mid-afternoon. Fast drain almost always has a findable cause: an app, a setting, the signal or the battery itself. Here is how to work out which one, in order of how often each is to blame.

The usual suspects

Battery drain on Android comes from four places. Go through them in this order, because the first ones are the most common and the quickest to fix.

1. The screen

On most phones the display is the single biggest power user. High brightness, a long screen timeout, a high refresh rate and an always-on display all add up. If your drain started after you turned brightness up for summer or switched off adaptive brightness, that may be the whole story.

2. An app working too hard

A new app, or a new version of an old one, can start syncing, tracking location or holding the phone awake in the background. Social media, video, navigation, games and some shopping apps are frequent offenders. One misbehaving app can easily double your drain.

3. Signal and radios

A weak mobile signal makes the modem work much harder, so a day in a basement office or on a rural train can drain the battery fast. GPS left on by a navigation app, a mobile hotspot, or constant Bluetooth and Wi-Fi scanning add to it.

4. A worn battery

If nothing else has changed and the phone is two or more years old, the battery may simply hold less than it did. A battery at 75% of its original capacity gives you a quarter less screen time from the same 100%. See when to replace a phone battery for the signs.

How to find what is draining your battery

  1. Open Android's battery usage page. On most phones it is under Settings > Battery, then Battery usage or App battery usage. The exact names vary by brand and Android version.
  2. Look at the top of the list. An app you barely opened that sits near the top is your prime suspect. Note whether its usage is mostly in the background.
  3. Compare screen time. If your screen time has gone up, the drain may just be more use. Settings > Digital Wellbeing (or Screen time) shows this on many phones.
  4. Check what changed. A recent app install, system update, new watch or earbuds, or a new place you spend the day are all clues.
  5. Watch it for a day. Charge to full, use the phone normally and check again in the evening. One snapshot can mislead; a pattern does not.

Android's own page resets after every full charge and often lumps activity into "Screen" or "Android system", so a bad day can vanish before you look. bCare's apps draining battery view ranks your apps by their share of screen time over the last 7 days and sends a fast-drain alert when the battery falls noticeably faster than your usual rate.

How to fix fast battery drain

Fix a draining app

  1. Open Settings > Apps, then the app.
  2. Open its battery setting and choose the restricted or optimised option, so Android limits its background activity. The label depends on your phone.
  3. Turn off notifications and background location if the app does not need them.
  4. Update the app. If the drain started after an update, check whether a fix is out.
  5. If you rarely use it, uninstall it. Many apps work just as well in a browser.

Fix the settings

  • Turn on adaptive or auto brightness and lower the slider a notch.
  • Shorten the screen timeout to 30 seconds or 1 minute.
  • Use dark mode if your phone has an OLED screen.
  • Turn off the always-on display if you do not need it.
  • Switch off hotspot, GPS and Bluetooth when you are not using them.
  • On a weak signal all day, use Wi-Fi calling or turn on airplane mode with Wi-Fi when you can.
  • Turn on battery saver when you need the phone to last; it limits background work and visual effects.

Restart and update

A restart clears stuck processes, and system updates often fix drain bugs. If drain started right after a major Android update, give it a day or two: phones re-index files and re-optimise apps after updates, which uses extra power temporarily.

When the battery itself is the problem

If the screen, apps and signal all look normal and the phone still empties quickly, check the battery's health. Some brands show it in Settings: see our guides for Samsung, Pixel and other brands. Many phones show little or nothing, which is where bCare's battery health check helps: it measures the real capacity in mAh during normal charges and compares it with the design capacity. A big gap means no setting will bring back the old battery life.

How bCare helps

bCare looks at drain from three sides at once: apps ranked by share of screen time, alerts when one app uses a lot of power or the battery drains faster than usual, and a "draining your battery now" list of settings such as brightness and screen timeout with a quick fix for each. The live monitor shows the discharge current in mA, so you can see the effect of closing an app straight away. A low battery alarm reminds you to plug in before a deep drain.