Windows 7 goes into hibernation immediately after the UPS kicks on

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.)

UPDATE

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

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.