Battery health issue

Try this:

How iPhone battery recalibration works in iOS 14.5

1. Once you install the iOS 14.5 on an iPhone 11, the battery recalibration process starts automatically. ... 
2. To check the status, head to Settings > Battery > Battery Health.
3. You'll see the new “Important Message” about the recalibration at the top.

please note it can take up to 15 days for this process to complete, after it is complete your battery health will be shown more accurately, chances are its health will increase. There was a software problem which reported inaccurate battery health in iphone 11, but the good thing is, this latest update will fix it. Be patient!

good luck

Hi, which iphone and ios version are you using? Don’t worry you don’t have to change the battery at 85, you can consider when it falls below 80. I had a 6s plus and my battery was 74 percent and i would still be ok with it. I just recently sold it.

Hi, nothing to worry about. As long as your battery is above the 80 percent mark your battery is supporting peak performance.