I updated to Android 15 two weeks ago, and now the battery drains in half a day with normal use. It used to last two days. I checked the settings - no new apps, no background processes either. Is this normal after an update or did something break on my end?
Most likely it's not a malfunction, but the system re-indexing itself after the update. When Android gets flashed, it rescans all the files, rebuilds the databases, updates search indexes - all of this runs in the background and drains the battery for several days. On the surface it might not show up in your app list, but there's serious stuff happening in the background. Try leaving your phone on the charger overnight and let it just do its thing - often after 3-7 days the battery consumption normalizes.
If nothing's improved after a week, check what's actually eating your battery. Open up the battery usage history by app and process (in Android this is usually Settings → Battery or Battery → Usage history). See which app is the biggest culprit. Sometimes after an update one of the built-in apps starts glitching and draining the battery constantly - like Google Play Services or the system search.
Last thing to try - clear the system cache. It's safe and often helps. Either through the app settings or through recovery mode (usually Volume Down + Power). If nothing works, you're left with a factory reset, but that's a last resort.
Don't rush to roll back - this is actually a temporary thing :) My phone drained the battery like crazy for a week after the update, then everything went back to normal. The system reindexes caches, recalibrates sensors, and there can be increased GPS and sync activity in the background. Try leaving your phone alone overnight or two with Wi-Fi on - if it's still reconfiguring itself, you'll see. If nothing's changed after a week, then start looking at a specific app that might be glitching after the update.
What both already said about reindexing is true. But there are a few other things. First, after an update a bunch of services often get turned on that were disabled in the old version. Go into battery settings and check which apps are eating the most power. Look not just at percentages but at how long they're active in the background. Sometimes you find unexpected stuff there.
Second, try rebooting and checking again. Once I updated my phone and the battery was jumping all over the place for like three days, then after a reboot everything got back to normal. The system just doesn't fully initialize right away, even if it looks like it loaded fine.
If nothing normalizes over a week or two, then it makes sense to dig deeper - clear the cache for system apps in settings, or worst case do a rollback. But don't rush it, give the system at least a week or so.
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