Important battery usage : why?

[aibd]

You can get clues from

Settings > Battery > Battery usage,

@aibd

If the phone is “wasting energy” somewhere then study of Battery usage can pinpoint trouble. Compare especially in a typical time slot

• View by apps vs
• View by systems.

In your case you might look for any evidence of inappropriate mobile data switching (common) or mobile data vs Wi-Fi.

Usually the comparison would probably reflect your guess. System apps, or mobile data coming to the top would tend to point to a culprit.