ups

At home I have an APC Back-UPS CS500 UPS (BK500) to ensure my systems have just enough time to power down gracefully when a poweroutage occurs (or keep working until the battery runs out). It includes a USB cable which you can connect to a machine (works perfectly with apcupsd) so the Operating System knows that the power is gone and you are running on battery power. CS500 - picture from APC