Direct answer
Overnight drain is usually revealed by Battery usage: background activity, weak cellular signal, navigation, syncing or battery condition. Measure one night before disabling broad features.
What this covers
- The observed symptom matches this record
- Customer-accessible settings, connections and external components
- Diagnosis before reset, deletion or component replacement
What it does not cover
- ×A model-specific error code with a different documented meaning
- ×Internal electrical, battery-cell, gas, refrigeration or sealed-component repair
- ×A guarantee that every model exposes the same control label
Capture the exact symptom
ReversibleOpen Settings › Battery after the drop and note the apps, screen-off activity and cellular signal period.
Run the smallest isolation test
ReversibleRepeat one night on known Wi-Fi with charging accessories disconnected and one suspect background feature limited.
Correct only the proven cause
ReversibleUpdate or reconfigure the app/service proven active; review battery health if the phone also shuts down under load.
Verify before changing anything else
ReversibleCompare percentage loss over two similar nights after the narrow change.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Exact questions
Common follow-ups
What should I check before resetting anything?+
Open Settings › Battery after the drop and note the apps, screen-off activity and cellular signal period.
What is the safest isolation test?+
Repeat one night on known Wi-Fi with charging accessories disconnected and one suspect background feature limited.
When should I stop troubleshooting?+
Service a swollen, unusually hot or physically damaged battery immediately.
Answer for the exact device and software version shown above.