windows 7 - System connected to UPS goes to sleep short time after power is lost

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

   
  42 
  2 
  4 
  64 
  0 
  0x8000000000000004 
   
  325242 
   
   
  System 
  xxxxx 
   


  4 
  4 
  2 
  0 
  

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?

Answer

I was not able to solve the issue despite of my efforts. I was not even able to get any more information on the "Microsoft-Windows-Kernel-Power" so far.

The best I could do was a workaround: instead of using native Windows battery management I have installed APCUPSD software and I can no longer observer the issue. With this sotware Windows are not aware of the battery, the APCUPSD controls shutdown directly and I have verified it is not doing so prematurely.

I guess using APC provided PowerChute might work as well, but I did not like the sofware much when I installed it, sounds too much cluttered and obtrusive to me.