iPhone 16 Pro Max overheating and requiring frequent charging after the iOS 27.0 update

• How many Charge Cycles are on your phone?
• When did you update?
• Are you seeing the Siri & Search Optimization has finished? If that is still being optimized in the background there will be a message just under your user name after opening Settings.
• Post the screenshot of the 2 battery graphs and the top 5 apps consuming your battery at Settings > Battery > View All Usage. Choose yesterday on the top daily graph, so the data for app usage show a full day instead of only the current day.

Welcome and thank you for reaching out. 🤗

It is normal for an iPhone to run warmer than usual for a day or two after a major iOS update due to background processes like indexing.

However, if the issue persists, there are several steps you can take to resolve it:

• Wait it out — Background tasks like photo indexing and data syncing can cause the phone to heat up temporarily after an update.
• Update your apps — Third-party apps may need updates to run efficiently on the new iOS version. Check the App Store for any available updates.
• Check your charger — Using a high-wattage charger can cause the phone to heat up. Try using a standard 20W charger or a different power source.
• Remove the case — Some cases can trap heat and prevent the phone from cooling down properly.
• Enable Low Power Mode — This reduces background activity and can help lower the phone's temperature.

If your iPhone continues to overheat, you may want to contact Apple Support for further assistance.

Good Luck! 👋🏼😉

Smiliñ 😎 Brian | Community Volunteer

Why is my iPhone overheating? - Apple Community

A further consideration is iOS 27 made major changes to iOS data structures, so all of the system data must be reorganized and the search tree must be rebuilt. This can take several days. It only runs when you are not actively using your phone, so most of that processing will run in background and potentially use a lot of energy.

For 93%, go to Settings/Battery/Battery Health. Note the cycle count. Now divide the cycle count by 50, and subtract the result from 100, and that should be close to your maximum capacity.