Display dims on battery - despite not using the respective setting

[BanjoDudeAhoy]

Hello. Whenever I unplug my M1 MBA and go from wall power to battery, the display dims.
That's despite the "Slightly dim the display on battery" setting being deactivated.

Any ideas why this is happening/what I can do to restore the correct behavior?

 

[bogdanw]

Have you tried turning it on and off again? I'm referring to the "Slightly dim the display on battery" toggle. Enable it, close System Settings, disable it.

 

[BanjoDudeAhoy]

Have you tried turning it on and off again? I'm referring to the "Slightly dim the display on battery" toggle. Enable it, close System Settings, disable it.

I felt stupid for not having tried it but I did it now - still the same: I pull the plug and the display gets noticeably dimmer

 

[bogdanw]

The setting is saved in /Library/Preferences/com.apple.PowerManagement.plist
To read the plist from Terminal

defaults read /Library/Preferences/com.apple.PowerManagement.plist

In Battery Power, ReduceBrightness = 0
If it's not, probably System Settings is not saving it correctly.
In any case, you could try to delete /Library/Preferences/com.apple.PowerManagement.plist and redo the settings from System Settings.

 

[adrianlondon]

Check the "low power" settings. If it switches to low power at any point, that dims the display. it's annoying, as I'd otherwise enable the low power when on battery.

 

[BanjoDudeAhoy]

The setting is saved in /Library/Preferences/com.apple.PowerManagement.plist
To read the plist from Terminal

defaults read /Library/Preferences/com.apple.PowerManagement.plist

In Battery Power, ReduceBrightness = 0
If it's not, probably System Settings is not saving it correctly.
In any case, you could try to delete /Library/Preferences/com.apple.PowerManagement.plist and redo the settings from System Settings.

That is 0, indeed.

But...

Check the "low power" settings. If it switches to low power at any point, that dims the display. it's annoying, as I'd otherwise enable the low power when on battery.

This is what it says for me.
Setting it to "Never" worked.

Now I'm not sure if this should be considered a bug. I think I'll check it on Sonoma later and if it does the same thing I might report it.

Either way, thanks to both of you

 

[adrianlondon]

Now I'm not sure if this should be considered a bug. I think I'll check it on Sonoma later and if it does the same thing I might report it.

I'm running Sonoma, and it does the same. I assumed it was deliberate.

 

[BanjoDudeAhoy]

I'm running Sonoma, and it does the same. I assumed it was deliberate.

It might be.
The reason I feel it might be a bug is that this the Low Power mode essentially cancels out another setting without that fact being mentioned. If using Low Power mode were to gray out the display dimming option with a note that you need to disable Low Power mode to be able to use display dimming on/off, that'd be a bit more transparent.

But I may be crossing over into UI/UX nitpicking mode here