Investigate battery drain by comparing activity, not just the remaining percentage. Check what the phone was doing during the affected period, note anything unusual, and change one setting at a time.
Read the activity breakdown
The iPhone Battery screen separates onscreen activity from background work. Background activity can explain usage even when an app was not visibly open. Consult the activity details rather than assuming the first app in the list is faulty. Understand your iPhone battery usage and health
On a Pixel, open Battery and review Battery usage. Google provides per-app controls and recommends keeping optimization enabled. These Pixel instructions are not a guarantee that another Android maker uses the same menu. Get the most life from your Pixel phone battery
Make a comparison you can interpret
Record the starting charge, charging periods, and the activities you remember. Compare a quiet day with another quiet day, not with a day of navigation and video. In a simple troubleshooting note, separate observations from guesses: an app used power in the background is an observation; that app is broken is a hypothesis.
Choose one nonessential behavior to test. For example, postpone a discretionary background task rather than disabling every communication tool. Keep a record of the original setting so you can undo the experiment if an important function stops behaving as expected.
Decide what to do next
If the same unexplained pattern repeats, collect screenshots of the battery breakdown and the device and operating-system version for the maker's support team. Avoid treating an online list of toggles as a universal repair.
This checklist helps organize evidence; it cannot diagnose a damaged battery. Physical damage or a device safety warning belongs with the manufacturer's safety and repair guidance, not a software experiment.