How to disable peak performance capability?

Hello Olaf52.

Thanks for reaching out to Apple Support Communities. We understand that your iPhone has been experiencing unexpected shutdowns and you would like to know if it is possible to disabled peak performance. We will be glad to assist.

Please see the information below from the following resource: iPhone Battery and Performance

Performance management applied

When the performance management features have been applied, you'll see this message:

This iPhone has experienced an unexpected shutdown because the battery was unable to deliver the necessary peak power. Performance management has been applied to help prevent this from happening again. Disable…

Note that if you disable performance management, you can’t turn it back on. It will be turned on again automatically if an unexpected shutdown occurs. The option to disable will also be available.

Cheers.

In Settings>Battery>Battery Health, what's listed for Maximum Capacity?

If it's 80% or less, you need a new battery.

~Lyssa

Hi Olaf52.

Thanks for following up. Take a look at this resource as well, which can help:

If your iOS or iPadOS device restarts or displays the Apple logo or a spinning gear unexpectedly 

Take care.

Once the health dips below 80%, you MAY start to see odd behavior. It sounds like your phone is showing that behavior, which means you should get the battery replaced.

~Lyssa