Optimise energy settings for a Mac notebook
If you have a Mac notebook, you can optimise your computer’s energy use to get the longest battery life when it’s not plugged into a power point or to get the best performance when it’s plugged in.
On your Mac, choose Apple menu > System Preferences, then click Battery.
You can set the computer or display to sleep at different times when you’re using the battery or connected to power.
Set sleep times for battery use: Click Battery, then drag the “Turn display off after” slider.
Set sleep times for power adapter use: Click Power Adapter, then drag the “Turn display off after” slider.
To save energy, click the Battery or Power Adapter pane, then select “Put hard disks to sleep when possible”.
To keep your display dimmed while using your battery, click Battery, then select “Slightly dim the display while on battery power”.