Battery Drain Overnight when airplane mode is off.

Hey,

A little while back I went through the process of restoring a 2020 iPhone SE, replacing its housing and replacing the screen. Although everything works well I have kept it in the closet and haven’t sold it due to a battery drain issue.

Regarding day to day use the battery life appears to be on par with most other 2020 SE’s, and has 89% Battery Health (genuine apple battery original to this iPhone). However, it continues to loose charge when the phone is off/‘stand-bye’. It is not irregular for it to loose 20ish percent from full, and even up to 30% overnight. Within three days even without use I wouldn’t the surprised if it has completely drained.

However, I tried turning Airplane mode on and the battery drain significantly reduced, to I think like within 10% (acceptable) in one night. Besides WiFi and my iCloud Account it is a running a clean version of iOS 14.4.2 and has no SIM Card or any apps/links running in the background. The screen itself was replaced, however it was with a genuine refurbished 8/SE Panel (so is an Apple LCD).

Just seeing if anyone has any ideas in what could be causing the issue before I sell it as is/consider opening it up again and investigating, just as I have sealed it down and don’t want to open it if it is an easy fix 🤪

Thanks (: