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I have a Win7 x64 system connected to the UPS. The UPS is capable of maintaining the system power for about 30 minutes. After I have connected the UPS, I have verified this by disconnecting the power cord and everything has worked as expected, I was receiving low level battery notifications and the system went off once the battery has reached the critical level. Since then a long time passed. Recently I was experiencing a power loss several times, and each time the computer went to sleep in a very short time.
I can reproduce this easily any time by disconnecting the power cord from the UPS. When I do this, the system correctly shows the battery level and the remaining battery time when I disconnect the cord (the level starts at 100 % and the remaining time at 0:32 and gradually goes down). Yet, the system sleeps after a short while without any warning.
I do not have any 3rd party software installed to manage the UPS, I am using default Windows battery handling. My advanced power settings when on battery are as follows:
- Sleep after: 20 Minutes
- Critical batter action: Sleep
- Low battery level: 20 %
- Critical battery level: 10 %
- Low battery notification: On
- Low batter action: Do nothing
- Reserve battery level: 7 %
When the system sleeps, following entry is shown in the event log:
The system is entering sleep. Sleep Reason: Battery
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Microsoft-Windows-Kernel-Power" Guid="{331C3B3A-2005-44C2-AC5E-77220C37D6B4}" />
<EventID>42</EventID>
<Version>2</Version>
<Level>4</Level>
<Task>64</Task>
<Opcode>0</Opcode>
<Keywords>0x8000000000000004</Keywords>
<TimeCreated SystemTime="2012-08-01T06:55:18.358031800Z" />
<EventRecordID>325242</EventRecordID>
<Correlation />
<Execution ProcessID="4" ThreadID="48" />
<Channel>System</Channel>
<Computer>xxxxx</Computer>
<Security />
</System>
<EventData>
<Data Name="TargetState">4</Data>
<Data Name="EffectiveState">4</Data>
<Data Name="Reason">2</Data>
<Data Name="Flags">0</Data>
</EventData>
</Event>
I have found a user reporting and solving a similar problem on Microsoft Answers, in his case the cause were broken drivers for Iomega drive. While I have quite a lot of devices connected to the computer, I do not have any Iomage drive.
- Is there any systematic way how could I troubleshoot this problem or identify which particular device is malfunctioning and causing the computer to sleep?
- Does some documentation for "Microsoft-Windows-Kernel-Power", which would help me understand the exact source of the event?
I have tried setting reserve level to 0 as advised in http://superuser.com/questions/454450/windows-7-goes-into-hibernation-immediately-after-the-ups-kicks-on?rq=1. Did not see any change. I wanted to change the Critical level to 0 %, but the system does not allow me to go below 10 % with this option. I wanted to disable the Critical battery action, but system does not allow me this, it offers only "Shut down" and "Sleep", there is no "Do nothing" for Critical battery action / On battery. :(
– Suma – 2012-08-01T07:58:34.8134Testing a UPS by pulling the plug out of the wall socket is a bad idea, because you are removing earth ground while a battery source continues to provide 120VAC to the equipment. You have created a potential shock hazard. The safer method is to plug the UPS into a power strip, and use the switch on the power strip to simulate a power outage. – sawdust – 2012-08-01T08:35:48.107
How old is the battery? Sounds very much like it's unable to hold it's charge more than a short time before it reaches 'critical'. – HaydnWVN – 2012-08-01T09:45:51.000
1@HaydnWVN The battery is 6 month old, but this is not a problem. The battery does not go off. It is the system sleeping itself. The battery still contains 85 % when this happens, power outpur is not interrupted, I am able to start the system many times while still running at it, only to have it sleeping in a short moment again. – Suma – 2012-08-01T11:17:14.327
Powercfg.exe -qh will also display power related settings that are not shown within Control Panel. You might want to check if there is something odd. – Tex Hex – 2012-08-09T18:02:22.770