Uninterruptible Power Supply APC Back-UPS BE-850VA:We would not wish it on our worst enemy. A power outage minutes before you saved that important document. Almost all your work has vanished, and you have to start again from nothing. Similar heart-stopping situations can be averted by the APC Back-UPS BE-850VA backup power supply. This is just another name for a large battery that powers all appliances needing electricity. The APC Back-UPS BE-850VA UPS has the Off-line design approach. Off-line is seen as the most basic form because it switches to the internal battery for electric power when power fails. APC Back-UPS BE-850VA Backup Power Supply Key Features Type of backup power supply: Off-line Actual performance: 520 W At a 100% load, the UPC will work for 2,3 min An important attribute is the battery run time. This is governed by the power consumption of the connected devices – for example, at half-load (50%), the UPS power time lasts much longer. The load of the UPS determines the operating time, which at full load is 2,3 min and at half-load, its 9,8 min. It is therefore necessary to calculate the power consumption of the connected appliances and it is a good idea to have a bit of energy extra left. The APC Back-UPS BE-850VA measures the apparent power as 850, but realistically, the actual power usage is 520 W.