How to re enable peak performance capability

Hi there anikmatun,

Thanks for posting your question! It looks like you want to know about manually activating Performance Management on your device.

Performance management is featured that helps to prevent unexpected shutdowns on your device. If you experience a shutdown and disable Performance Management after, you would not be able to manually turn it on. This is covered in the text below, from the link titled 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."

We hope this answers your question.

Kind regards.