Computer shuts done Immediately at lose of power

[Anonymous user]

when losing power my computer shuts down immediately. Then I can turn computer back while still on battery backup and it says I have 90%+ battery left. I have another computer and it stays on and all the settings are the same......it's set to leave computer on until there's 5 mins left

any ideas?

[Anonymous user · Accepted solution]

To make a long story short, the most common cause of this problem is a computer power supply that is incompatible with the modified sine wave output provided by many uninterruptible  power supplies when the power has failed. (The only fixes are to either replace the computer's power supply with a unit that can tolerate the output of your UPS, or to utilize a UPS having a true sine wave output.)

There is also the possibility that your UPS is overloaded. It would be helpful to know which APC  UPS you have, and what kind of system you are using it with. (I personally do not recommend any UPS smaller than 750 VA or so for *any* computer power backup application.)