Can’t Change Critical Battery Level in Windows 7

battery So with the heavy rainstorms we’ve been getting these pass few days, I’ve been having quite a few brown outs. Everything’s fine though since my computers are all backed by UPSes. However I do noticed that my HTPC always seems to hibernate whenever these brown outs occur. I checked the battery and it was at 99-100%. So I went into the power settings and noticed that the critical battery level action was set to hibernate and the critical battery level was set to 98%. I tried changing it to 10%, but the setting would revert back to 98% immediately after trying to apply changes.

I did a search and found the following 2 threads:

I tried to do what a few suggested such as changing my group policy for reserve battery notification, changing my permissions settings for power schemes in the registry, and a few others, but they all failed to work. The only thing that worked was running the powercfg.exe tool.

powercfg.exe -setdcvalueindex 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c e73a048d-bf27-4f12-9731-8b2076e8891f 9a66d8d7-4ff7-4ef9-b5a2-5a326ca2a469 20

The 2 things you need to change are 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c (power scheme GUID) and 20 (what percentage to set it to). To locate your power scheme GUIDs, open registry editor (regedit.exe) and go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\User\PowerSchemes. The keys (i.e. folders) underneath that location are your GUIDs. I believe the GUID above is for the High Performance power scheme.

Here’s the command to set the Balanced power scheme to have a critical battery level of 10%:
powercfg.exe -setdcvalueindex 381b4222-f694-41f0-9685-ff5bb260df2e e73a048d-bf27-4f12-9731-8b2076e8891f 9a66d8d7-4ff7-4ef9-b5a2-5a326ca2a469 10

6 thoughts on “Can’t Change Critical Battery Level in Windows 7

  1. Oh man, EXACTLY my problem and EXACTLY what I needed…. thanks. WHY is this so stupid in Win 7?? Why make the GUI for advanced power settings and then not let someone change the setting via the GUI?

  2. Thanks for writing this up. This was sooo pissing me off. Get a brown out, computer goes to hibernate despite my UPS being fully charged. Now at least it shouldn’t kill me while I’m playing poker…lol

  3. The GUID’s seem to be the same across systems, (except for custom ones you create) so the power saver one is here:
    C:\Windows\system32>powercfg -l

    Existing Power Schemes (* Active)
    Power Scheme GUID: 381b4222-f694-41f0-9685-ff5bb260df2e (Balanced) *
    Power Scheme GUID: 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c (High performance)
    Power Scheme GUID: a1841308-3541-4fab-bc81-f71556f20b4a (Power saver)

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