Alter (auto) Power settings when plugged in or on Battery Power?

I'm running a laptop and would love for the power settings to automatically
change from high performance when plugged in to Ballanced or Power Saver when
running on Batteries. Does the system do this....?

What I just did about five seconds ago was reset the power saver optio
to default, then set the computer on high performance before unpluggin
it to make sure it worked. sure enough, the battery performance change
when I both unplugged it and plugged it back in. I hope this helps

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Darkingfire