Android battery drains overnight even when not in use

Symptoms

• Battery drops 10% or more overnight without any use
• Phone is warm in the morning despite sitting untouched
• Standby drain is worse in one location, like the bedroom, than others
• Battery usage stats show high overnight activity from a specific app

Likely causes

• CommonAn app running background tasks or syncing overnightSome apps schedule syncing or refresh tasks during typical low-usage hours.
• CommonPoor cell or Wi-Fi signal overnight causing constant reconnection attemptsWeak signal in a bedroom, especially in a basement or far from a router, forces the radio to work harder even while idle.
• PossibleNotifications or alarms triggering brief wake-ups repeatedlyFrequent overnight notifications, like from group chats in different time zones, add up.
• PossibleA stuck app or process consuming CPU overnightOccasionally an app fails to go fully idle and keeps using resources.
• PossibleDegraded battery amplifying otherwise normal overnight drainA weaker battery shows a larger percentage drop for the same actual power draw.

What to do

1. Check Settings > Battery the next morning and look at the overnight breakdown by app.
2. Identify any app with unusually high background activity relative to typical overnight standby.
3. Check Wi-Fi and cell signal strength in the room where the phone charges overnight.
4. Turn on Airplane Mode with Wi-Fi enabled overnight as a test to see if drain improves significantly.
5. Turn off notifications or set a Do Not Disturb schedule overnight to reduce wake-ups from alerts.
6. Update or reinstall any app showing consistently high overnight usage.
7. Restart the phone before bed occasionally to clear stuck background processes.
8. If drain remains high with no clear app or signal cause, check battery health for reduced capacity.

When to call a pro

If overnight drain stays high after ruling out apps and signal, and battery health is reduced, a replacement is the most direct fix.

Safety