Android Battery Drains Overnight While You Sleep
Short answer
Healthy overnight standby drain is 1-3% over eight hours on Wi-Fi, and up to 5-8% on mobile data with weak signal. Anything above 10% means something is holding the phone awake. Check Settings → Battery → Battery usage in the morning, switch to full device usage, and look for an app with high consumption and near-zero screen time — or for "Mobile network standby" at the top, which means poor signal rather than any app.
On this page
You charge the phone to 100%, put it on the nightstand, and pick it up eight hours later at 68%. Nothing was running. The screen was off the whole time.
Standby drain is the easiest battery problem to diagnose precisely, because there is only one variable: the phone was idle, and something was not. Eight hours of nothing is a clean experiment, and the battery statistics from an overnight period are far more readable than a day’s worth of mixed use.
What normal actually looks like
Before diagnosing anything, decide whether you have a problem.
| Conditions | Expected loss over 8 hours |
|---|---|
| Wi-Fi, no always-on display, few sync accounts | 1-3% |
| Wi-Fi, always-on display enabled | 6-12% |
| Mobile data, good signal | 3-5% |
| Mobile data, weak signal | 5-10% |
| Any of the above, battery over two years old | Add a few points |
Below 3% on Wi-Fi is a well-behaved phone. Between 5% and 10% is worth a look if you did not enable the always-on display. Above 15% means something was genuinely running, and above 25% means something ran the entire night.
One thing to rule out first: the percentage readout itself. A worn cell reports charge non-linearly, so a phone that shows 100% at bedtime may have been at an effective 92% and simply caught up overnight. If your phone also drops in sudden 10-point steps during the day, that is the shape of a tired battery rather than a rogue app.
Read the overnight statistics
Do this in the morning, before you have used the phone for much, while the overnight period is still most of the recorded history.
Open Settings → Battery → Battery usage. On both stock Android and Samsung there is a three-dot menu that switches to the complete view — labelled Show full device usage on Pixel and Show system apps on One UI. The default view hides exactly the entries that explain standby drain.
Then read it this way:
| What is at the top | What it means |
|---|---|
| An app, with near-zero screen time | That app ran all night. Act on it. |
| Mobile network standby | Weak signal. The modem was transmitting hard. |
| Android OS or Android System | Usually a stuck wakelock or sync loop. |
| Screen | Something woke the display, or always-on is enabled. |
| Nothing stands out, loss is spread evenly | Battery wear, not software. |
The split between foreground and background time is the whole diagnosis. An app that used 12% with three hours of screen time is doing its job. An app that used 12% with ninety seconds of foreground time, overnight, is the problem. The full method for reading that screen goes deeper on the day-to-day version of this.
The four causes that explain most cases
A sync account that cannot authenticate
This is the most common and the most satisfying to fix, because the effect is immediate. An email, calendar or cloud account whose password has changed, whose server moved, or whose token expired will retry its sync indefinitely. Each attempt wakes the CPU and the radio. A single broken corporate email account can cost 15% a night on its own.
Go to Settings → Accounts (Settings → Accounts and backup → Manage accounts on Samsung) and look for any account showing a sync error or a warning badge. Remove it and add it back. If you no longer use it, remove it and stop there.
Poor cellular signal
Not an app, and nothing you install will help. When signal is weak the modem raises transmit power and re-scans for towers continually. “Mobile network standby” or “Cell standby” high in the full-device view is the signature, and it is extremely common in bedrooms at the back of a house or in basement flats.
The fix is to stop the radio working so hard overnight:
- Turn on Wi-Fi calling if your carrier supports it, so calls route over broadband and the phone stops fighting for cellular.
- Leave Wi-Fi on. A phone on Wi-Fi uses dramatically less power than one on mobile data, which is the opposite of what most people assume.
- If you genuinely have no signal at home, airplane mode with Wi-Fi re-enabled is a reasonable nightly habit.
The always-on display
Typically 5-10% across a night, sometimes more on larger panels. Most implementations use a motion or proximity sensor to switch off in a pocket, but a phone sitting face-up on a nightstand has no reason to think it is unseen.
Turn it off, or set it to a schedule that excludes your sleeping hours. On both stock Android and One UI it lives in the lock screen section of settings, where the scheduling option is next to the on/off switch.
A single misbehaving app holding a wakelock
An app can request that the CPU stay awake. Done correctly this lasts a few seconds while work completes. Done badly, or triggered by a bug, the request is never released and the phone cannot enter deep sleep for the entire night.
Fitness trackers, delivery apps, smart-home apps and anything with a persistent location permission are the frequent offenders. The telltale is a warm phone in the morning.
To act on a suspect: Settings → Apps → [app] → Battery on stock Android, or the equivalently placed battery section of app info on One UI, and set it to Restricted. That stops it running in the background entirely.
Restricting an app delays or kills its notifications. That is the right trade for a shopping app or a game and the wrong one for your messaging app, so do not apply it indiscriminately. If alerts later stop arriving and you have forgotten why, delayed Android notifications covers the reverse problem.
Test it properly in one night
Guessing is slower than measuring. Do this instead.
- Charge to 100% and note the exact time.
- Put the phone in airplane mode with Wi-Fi off, screen off, face down.
- Check the percentage in the morning.
A phone with everything disabled should lose under 1% across eight hours. If it still loses 10%, no app is responsible and the battery itself is the answer — run through the wear symptoms rather than hunting software.
If airplane mode is clean, repeat the next night with Wi-Fi only, then the night after on mobile data. Two nights of patience identifies the layer precisely.
Tighten the settings that matter overnight
Worth doing on any phone, and these are the ones with real effect rather than folklore.
- Adaptive Battery on. It learns which apps you never open overnight and stops scheduling them.
- Location permissions set to Allow only while using the app for everything except navigation. A persistent location permission is the single most expensive one to grant.
- Background data off for apps you do not need live: Settings → Apps → [app] → Mobile data and Wi-Fi.
- Wi-Fi scanning and Bluetooth scanning off under the location settings. Both wake the radios periodically even when Wi-Fi and Bluetooth are “off”.
- Remove unused accounts. Every account syncs on a schedule whether you read it or not.
Samsung users have one additional lever worth knowing about: the background usage limits section of the battery settings lets you put specific apps into a deep sleep list, where they never run in the background at all. It is more aggressive than Restricted and breaks notifications completely for those apps, which is fine for the right apps.
What does not help
- Battery saver apps. They cannot hold the system permissions needed to control other apps, so they kill processes Android then restarts, at a net loss, while running constantly themselves.
- Closing every app before bed. Android has already suspended them. A suspended app is free; a cold start in the morning is not.
- Turning off Wi-Fi overnight. Counterproductive. The phone falls back to mobile data, which costs more power, and it keeps scanning for networks anyway unless you disable Wi-Fi scanning separately.
- Lowering screen brightness. Irrelevant to a screen that is off.
Realistic expectations
A phone with one broken sync account typically goes from 25-30% overnight loss to 2-3% the same night the account is removed. Switching off the always-on display is worth most of a tenth of the battery on its own.
If you have done all of it and still lose 10% a night with nothing in the statistics to blame, you are looking at cell wear. A battery past roughly 500 full charge cycles — year two for most people — holds less and reports what it holds less accurately. Replacement is the fix, and no setting substitutes for it.