Yesterday I had to write a script to do some initial setup on Windows and one of the steps was configuring power settings. I remembered that there were few useful options, but googling them did not help me. Luckily I found the pieces in an old script I wrote. So here are few tips for using powercfg.exe
Use Guid aliases
In many online resources you find commands like these:
powercfg.exe -SETACVALUEINDEX ` |
Using Guids is great for compatibility, but awful for readability. So if you are on Windows 7 or newer use aliases instead. You can list all the aliases by powercfg.exe -aliases which is missing from the help for some reason.
a1841308-3541-4fab-bc81-f71556f20b4a SCHEME_MAX |
It gives you are very nice hierarchical table, but it’s a bit difficult to guess what exactly the alias means. A better way to lookup the information is by powercfg.exe -query, especially if you reduce the output to only show the alias and the line before it:
powercfg.exe -query | Select-String 'GUID Alias' -context 1,0 |
Inspecting the full output we can easily figure out that the command above translates to:
powercfg.exe -SETACVALUEINDEX SCHEME_BALANCED SUB_SLEEP STANDBYIDLE 3600 |
Which is a valid powercfg.exe command and can easily be understood as “On Balanced scheme, when connected to electric outlet, sleep after 1 hour of idleness.”.
Use schema aliases
In the previous command we used SCHEME_BALANCED to change built-in Balanced scheme. And there are also SCHEME_MIN for the Maximum performance, and SCHEME_MAX for Power saver scheme. The alias names are a bit backwards, because MIN stands for minimum power saved -> Maximum performance, and vice versa for MAX.
The three aliases above are easy to discover, because they are listed on the top of the -alaises table, but there are two more that are extremely useful:
SCHEME_ALL pointing to all schemes. This one saves you ton of work when you try to make some settings consistent over all available schemes.
SCHEME_CURRENT pointing to the currently active scheme. This one is extremely useful when applying changes that require re-activation of the scheme. In that case you can simply do powercfg.exe -setactive SCHEME_CURRENT. It looks like non-sense, but without it some of the settings won’t work.
These two aliases you can discover by using -aliasesh parameter which lists all aliases, including aliases for hidden settings.
Inspect hidden settings
The tool can change way more then it seems. There is probably a good reason to hide most of the options by default, but listing them could be more obvious. Listing all the settings can be done by using an undocumented -qh switch (no -queryh does not work), which on my system yields 137 options vs. 31 options for the normal query.
powercfg.exe -qh | |
Most of the settings you should not fiddle with, but for example setting the time to turn off display on lock screen from the default 1 minute to 10 seconds can be done like this:
powercfg.exe -setacvalueindex SCHEME_CURRENT SUB_VIDEO VIDEOCONLOCK 10 |
Making the settings visible is possible via -attributes, but the settings apply even when hidden so I am not sure why you would need to do it:
# show hidden setting |
Reset to default
It is always a good idea to make backup when fiddling with important system settings, but if you didn’t and now you want to revert all your changes, simply call powercfg.exe -restoredefaultschemes to put everything to it’s initial state.