Standby battery drain on iPhone 7 Plus after iOS 15.8.5 update

Question

Hadidehaghin Author

Level 1

4 points

Standby battery drain on iPhone 7 Plus after iOS 15.8.5 update

Hello Apple Support,

I am experiencing excessive battery drain on my iPhone 7 Plus after updating to iOS 15.8.5.

Even when the phone is idle (standby), the battery percentage drops rapidly.

I have tried all recommended steps such as:

- Disabling Background App Refresh

- Turning off Location Services for unnecessary apps

- Disabling Siri & Search Suggestions

- Pausing iCloud Photos sync

- Using Low Power Mode

- Resetting all settings

but the issue persists.

Device details:

- Model: iPhone 7 Plus

- iOS Version: 15.8.5

- Battery Health: 92%

This appears to be a software-related issue affecting standby battery drain.

Please advise on any further steps or upcoming software updates to fix this problem.

Thank you.

[Re-Titled by Moderator]

Original Title: IOS 15.8.5 battery problem

Earlier iPhone models

Posted on Oct 24, 2025 4:27 PM

Reply

Answer 1

Kurtosis12

Level 9

79,190 points

Oct 24, 2025 4:36 PM in response to Hadidehaghin

Is the original battery in the phone?

If so, you are getting a false reading of 92%.

If it was replaced, who replaced it?

Batteries degrade over time with usage due to chemical aging.

You can expect about a 1% drop per 50 charging cycles (25 charging cycles for IPhone 14 and older) with average use on an iPhone. This is an approximation, that is why it may be plus or minus a few percent on a month to month basis.

Apple recommends replacing it when it reaches 80%. To check your battery health, go to Settings > Battery > Battery Health.

iPhone Battery Replacement.

iPhone Battery Replacement - Apple Support

About Lithium Ion Batteries

iPhone battery and performance - Apple Support (IN)

Reply

Standby battery drain on iPhone 7 Plus after iOS 15.8.5 update

Similar questions