August 24, 2010, 7:48 AM — by Daniel P. Dern - A (good) surge protector can protect electronic devices that can tolerate losing power, whether for a fraction of a second, or a few hours, like printers, scanners, or a television. (Unless it's being used for something that you can't afford to have be stopped or interrupted.)
But to ensure your computer, external hard drive/file server/media center, cable box/DTR, router, answering machine and other devices not only are protected but also don't stop, you need an Uninterruptible Power Supply (UPS).
UPSs fall into the same categories as backups: 1) things that desktop computer users need, and 2) things that are far easier and less expensive to get ahead of time than to discover you should have. For desktop/SOHO users, UPSs are available for anywhere from $50 to $200. Because getting the wrong one may be as bad as not having one at all, here are 5 tips for selecting a desktop UPS.
[ See also: What to look for in online backups ]
1. ENOUGH POWER
One of the two ways that UPSs are sized is the amount of power they deliver, usually stated in Volt-Amps (VA).
If the computer, monitor and whatever else you plug into the UPS' Battery Backup outlets call for more power than the UPS can deliver, the UPS won't work when there's no power; they're not set to prioritize based on outlet or whatever.
A good UPS will sense that you've plugged in more stuff than it can provide backup power for, and fail or alert instantly to let you know you've plugged too much in. But some won't, so be sure to try it out, with everything powered up, but no unsaved files open, by removing the UPS plug from the wall, and see what happens.
Higher-power UPSs cost more than lower-power ones, so you need to strike a balance between power and price. Also, vendors can calculate how much power a device uses in different ways, so you can't simply add device power numbers up. Plus, some devices draw more when starting up, or in heavy use.
2. RUN TIME
How long will the UPS supply power?
That UPS battery isn't a Green Lantern Corps Power Ring that's good for 24 hours. Desktop UPSs are typically good for five to twenty minutes of power, depending on how big the battery is, and how much/little stuff you're powering.