Hi. Actually if it is a device for you you should buy something of quality. Generics usually give problems in a short time. Use of the TRV brand of different powers and they work very well years ago. They come with soft programming of power off, charging and battery status, etc. You have to have two issues present before choosing it. One is its power. With 800W or 800VA you will be well powered for the consumption you mention. The other parameter is autonomy. The more amperes hour A / h the backup battery has, the more autonomy the device will have. An internal battery of 7 A / h like the ones you usually bring, for the charge you mention it will last a maximum of 5 minutes. If you want to be with the PC working at the time of cutting you can buy a UPSW with external battery and place a deep cycling of the capacity you want. In the workshop I have one of 400W with a battery of 12V 75 A / h and we operate a 26 "fan for about 8 hours. A greater capacity greater autonomy but verifying (by the manufacturer or seller) what maximum capacity you can place. This is so that the internal charger charges efficiently and to the maximum the battery. You can use a car battery without problems but these are not usually of deep cycling. This means that they are not prepared for a deep discharge.