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I have a UPS that will power my desktop computer for 50 minutes. The idea was that if the power when out I could save/make notes on what I'm working on and then shutdown or hibernate the desktop. But when the UPS looses power from the grid Windows 7 on my desktop goes into hibernate almost immediately.

I have the following settings:

Critical battery action: hibernate 
Critical battery level : 30%
Low battery level      : 40%
Reserve battery level  : 20%

It's also INCREDIBLY annoying to have to dive 17 miles to the office and back to just press the power button so I can fix an after hours issue that I could otherwise fix from home. All because there was a 30 second power outage.

I would use the APC's PoiuerChute but it doesn't support hibernation. Just shutting down. :S

More info: The Windows power utility is reporting the battery level correctly. (I'm doing the test again just to double check.)


After getting things working, a Windows update killed it again. So I just unplugged the cable. It was more trouble then it was worth.

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maybe it's similar to this question and could be worth to be watched, although this question seems to be about a desktop with an UPS and not a laptop. – wullxz Jul 27 '12 at 16:36
How about you just take the laptop home with you, so you don't have to worry about it being affected by a power outage at work? – Iszi Jul 27 '12 at 17:37
@Iszi I seriously doubt this is about a laptop. Since they already have their own battery power it is all but pointless to attach a UPS as well. – techturtle Jul 27 '12 at 18:21
@Iszi - I said nothing about a laptop. I could take my computer home every night. But hauling desktop tower home on my motorcycle wouldn't be very fun. – NitroxDM Jul 27 '12 at 18:22
@Iszi - If you attach a UPS that Windows is happy with, Windows will show the same battery icons you get on a laptop. – NitroxDM Jul 27 '12 at 18:26
up vote 1 down vote accepted

Have you tried changing your critical battery level to something far lower, like 5% or less? It's possible that under load the UPS is instantly telling Windows that it is below 30% (even if it stays there the full 50 mins) and thus triggers your machine to hibernate. You may want to turn down (or off) the reserve power level as well. Since you plan to hibernate the machine, not keep it in suspend, you should not need any power left in the UPS. I'm not sure how the "reserve" setting works in Windows, but if it calibrates that as 0% battery for the other settings, then the hibernate would actually be triggering at 50%.

Two other options to consider for your setup: First is to go into your computer's BIOS/UEFI and locate the State after power loss setting and change it to ON. If the power outage is serious enough to actually drain the UPS, this should allow the computer to come back on automatically once power is restored. Second, while still in the BIOS, set up wake timers (if yours supports them). If you set it to wake up every hour or two, this should attempt to resume it from hibernation periodically in the event that the computer goes into hibernation incorrectly.

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I unplugged the data from the UPS and ran it down to 45% and then restored grid power and then reconnected the data. Windows then showed the battery at 45%. So I don't think it's a communication issue. I'll monkey with the things you suggested. – NitroxDM Jul 27 '12 at 21:07
It's not so much that it's communicating wrong, but batteries measure differently under load than they do "at rest" or in a charging state. You might try disabling Hibernate and Suspend and then disconnect the grid power and see what Windows says the battery percentage is. My guess would be that, at least briefly, it will register below 30%. – techturtle Jul 27 '12 at 21:16
The reserve was the kicker. Setting it to 0% fixed the issue... so far. Now to run on the battery and see if it actually hibernates. – NitroxDM Jul 27 '12 at 21:36
Windows updated.... now I have the issue again. I'm thinking it's time to ditch the flawed OS's power management system. – NitroxDM Sep 25 '12 at 14:51
You could always just use the UPS w/o the management cable plugged in. Windows would be ignorant of the UPS then, so short outages would be unnoticed. You wouldn't be able to use hibernation still, but if you do what I suggested in the 2nd paragraph, you might come out the same. – techturtle Sep 25 '12 at 15:39

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