PC hibernating immediately after power fluctuation

[Anonymous user]

I've got an NS 1250 Back UPS supplying a power-hungry gaming machine running Vista x64. It's got an 800w PS that draws about 240w at average use/idle (which is usually when the power goes, or when I've run tests). The UPS is getting old, verging on about 3-4 years, if I remember correctly. I'm aware that the battery might be going south on me, but from the looks of PowerChute it isn't there yet.

When any power fluctuation, brownout, black out, pulled plug, etc., occurs, my computer immediately hibernates until the power is restored. I've checked Vista's power settings, and turned off all sleep/hibernate functions for all instances. I've set PowerChute to hibernate my machine when there's 5 minutes left on the battery. According to PowerChute, the battery still has (more or less) the estimated running time that should be left when it wakes up, so I'm fairly sure that the battery is at least functioning. When self-testing it does the same thing, immediately hibernating my computer. When running a manual test (i.e. pulling the plug) it does the same thing. No lights other than "On Battery" are lit. Whenever my computer wakes up from hibernation, PowerChute says first that it can't find the UPS for a couple seconds and then finds it. Also all operating history data, including self-tests, is missing.

For all intents and purposes it appears that PowerChute, or my computer at least, doesn't seem to know how much battery life is left, so it immediately hibernates. Does anybody have any idea what is causing this, and if there's any sort of solution? Is it really just a bad battery?

[BillP · Accepted solution]

the runtime reported by the UPS while it is online is an estimate. if its an older UPS, it could be off a little bit. what i would do is disconnect any non critical load from the UPS and then remove the data cable from the computer to prevent any shutdowns. i would then pull the plug from the UPS with a non critical load, like a lamp, and see how long it actually runs on battery. make sure to let it turn till it turns off. then lets compare that to what the software says. this will do somewhat of a calibration on the UPS.

also, when the computer resumes from hibernate, it is normal to lose communication with the UPS for a minute or so because in hibernate, the USB ports on the computer power down.