Just bought an OG SE 128gb for 100$. The battery health is 94% and the guy told me it has never been repaired.
The problem I’m facing is that the battery is draining very quickly from 100% to like 80% (I can actually see it drop 1% every couple of seconds).
After 80% it starts to slow down normally.
What could be the cause for this?
Definitely replace the battery. That battery is probably original and has been in that phone for a long time. A battery replacement will make a huge difference.