I'm moving from an Air to iMac soon. I've been using the Air as my alarm clock: it wakes from sleep off battery power till I get up, and turn my power on. Since I turn the power off at night, would it be possible to use a UPS battery backup to keep the iMac in sleep mode all night then wake in the morning for a couple minutes, till I turn the power on? How much power does an iMac in sleep mode need? Should a UPS be sufficient to last all night, plus a couple minutes awake in the morning? Would this might work: http://www.amazon.com/APC-BE550G-Back-UPS-Outlet-550VA/dp/B0019804U8 Thanks for any advice or info!