Battery health

Hello Bassem-B,

Thanks for posting in the Apple Support Communities. We're happy to look into this with you. We understand that you've seen a drop in the iPhone battery health since the iOS update. The change you saw with the Maximum Capacity, could be due to recalibration under the new iOS. However, since it's recommended that batteries be replaced once they drop below 80% maximum capacity, it would be best to have it checked out.

iPhone Battery and Performance - Apple Support

Your battery's maximum capacity

The Battery Health screen includes information on maximum battery capacity and peak performance capability. 

Maximum battery capacity measures the device battery capacity relative to when it was new. A battery will have lower capacity as the battery chemically ages which may result in fewer hours of usage between charges. Depending upon the length of time between when the iPhone was made and when it is activated, your battery capacity may show as slightly less than 100%.

A normal battery is designed to retain up to 80% of its original capacity at 500 complete charge cycles when operating under normal conditions. The one-year warranty includes service coverage for a defective battery. If it is out of warranty, Apple offers battery service for a charge. Learn more about charge cycles.

As your battery health degrades, so can its ability to deliver peak performance. The Battery Health screen includes a section for Peak Performance Capability where the following messages may appear.

If you'd like to look into your options for an inspection, and possible battery replacement you can review your options here: iPhone Service & Repair - Apple Support.

Best regards.