The 1 Hidden Background Setting on Android and iPhone That Drains 40% Battery
My phone started dying at four in the afternoon. Not after a heavy day: after a normal one, where I'd maybe taken two calls and looked at a map once. I did what everyone does: blamed the battery, blamed the last software update, and bought a $30 battery case that was so bulky it didn't fit in my pocket and lived in a drawer within a fortnight.
Then I actually opened the battery screen and read it properly, which I had somehow never done in years of owning smartphones. Sitting there at 14% of my entire day's battery was a weather app. I had opened it twice that week. Every bit of that 14% was background activity, and it had "Always" permission for my location, so it had been quietly waking up and pinpointing me all day, every day, for months.
I changed two settings. The phone now gets to eleven at night with about a quarter left.
What's actually going on, minus the clickbait
Let me be straight about the "one setting" framing: there isn't one magic toggle, and any specific percentage depends entirely on which apps you've installed. What is true is that on both platforms there's one category of behavior responsible for most mystery drain: apps doing things while you aren't looking at them.
That comes in two flavors. Background refresh, where an app periodically wakes up to fetch new content so it's ready when you open it. And background location, where an app asks the phone where you are even when it isn't on screen. The second is dramatically more expensive, because it fires up the GPS radio, and radios cost far more power than processing does.
The reason this stays hidden is that none of it is visible. There's no animation, no sound, nothing on screen. The only place it shows up is in the battery statistics, which almost nobody reads, and when they do, they read them wrong, which is the next section.
Step 1: Read your own battery screen before changing anything
Open your battery settings and look at the per-app breakdown over the last 24 hours and the last 10 days. On an iPhone that's Settings, then Battery; on Android it's Settings, then Battery, then battery usage: the exact wording moves around between versions and manufacturers, but every phone has it. Don't skip to the toggles below. Your list will be different from mine, and this screen tells you which two or three apps are worth touching.
My Expert Tip: Look at the split between screen-on time and background activity, not at the size of the number. The app at the top of your list is usually the one you use the most, and battery spent while you're looking at the screen isn't waste, that's just you using your phone, and restricting it only makes the app worse. The real thief is further down: the app at 5 or 6% whose usage is almost entirely background. That's an app you barely open charging you rent all day. I ignored my weather app for months precisely because it wasn't near the top of the list, while the video app at 22%, all of it screen-on: looked like the villain and was completely innocent.
Step 2: On iPhone, take control of Background App Refresh
Go to Settings, General, Background App Refresh, and either switch off the apps that don't need it or set the whole thing to Wi-Fi only. The top control has three options, Off, Wi-Fi, and Wi-Fi & Cellular, and moving off the third one alone makes a real difference, because it stops apps refreshing over mobile data when you're out and the signal is weak, which is the most expensive time for a radio to do anything. Then go down the per-app list and turn off everything you don't need updated before you open it.
Step 3: On Android, restrict the offenders individually
Open Settings, Apps, pick the app, then its Battery section, and set it to Restricted, and leave Adaptive Battery switched on. Restricted means the app essentially doesn't run in the background at all until you open it. Do this for the specific apps your battery screen flagged rather than for everything, because blanket-restricting is how people end up with messages arriving three hours late. Manufacturer skins name these things differently, but the per-app battery option is always in there somewhere.
Step 4: Fix location permissions: this is the big one
Go through your location permissions and change everything from "Always" to "While Using the App," and turn off precise location for anything that doesn't genuinely need it. This was worth more than every other change combined for me. Almost nothing needs your location while it's closed: navigation while it's running, a fitness tracker during a workout, maybe a find-my-device service. A weather app does not need to follow you around a supermarket. Do this one even if you skip the rest of the article; it's a privacy improvement as much as a battery one.
Step 5: Stop the unnecessary wake-ups
Turn off notifications for apps you don't act on, and set rarely-used mail accounts to fetch on a schedule instead of pushing. Every notification wakes the screen and the radio, and a phone that lights up forty times an hour is spending real power on things you swipe away without reading. This has the pleasant side effect of a calmer day. Keep push on for the things that matter: messages from people, calendar alerts, anything safety-related.
Step 6: Check back in two days, and don't break useful things
Look at the battery screen again after a couple of days and see what changed: then undo anything that caused a problem. If your messaging app now delivers late, take it off the restricted list; delayed messages are not worth 3% of a battery. Leave alarms, two-factor authentication apps, health monitoring and emergency features completely alone. And if your phone is several years old, check its battery health figure, because at some point the honest answer is a replacement battery rather than another setting.
What this was actually worth
My phone went from dead at 4pm to roughly 25% left at 11pm: call it six or seven extra hours on an ordinary day, from about ten minutes of tapping through settings. I stopped carrying a power bank on normal days, and the $30 battery case in my drawer remains a monument to solving a problem without diagnosing it first.
Your numbers will be different, and I'd be suspicious of anyone who promises you a specific percentage without having seen your phone. The useful part isn't the toggles, it's the battery screen: five minutes reading it tells you exactly which two apps are costing you an afternoon, and it's the same five minutes whether your phone is new or four years old.
Open your battery settings right now and find the app with the most background activity: then hit the share buttons below and send this to the friend who's always asking if you've got a charger.
