The same UPS that powers a PC only for about 20 minutes will likely run your gateway and router a good deal longer — perhaps for several hours.

by Joseph Moran

Aside from regularly backing up your hard drive, keeping your computers and network hardware plugged into a uninterruptible power supply (UPS) is another wise data protection practice. By so doing, you ensure that in the event of a power failure you’ll still have enough juice to shut down your computer normally, and prevent an abrupt shutdown from causing damage to your operating system’s configuration or the loss of open but unsaved files.

When powering an average desktop system, a typical UPS device will last anywhere from 5 to 20 minutes. (UPS devices with longer run times are available, but their large sizes and price tags make them impractical for home use.) But unlike a desktop PC that can swill electricity like Gatorade at a track meet, a DSL/cable gateway and broadband router (wired or wireless) both consume relatively small amounts of power. Therefore, the same UPS that powers a PC only for a few minutes will likely run your gateway and router a good deal longer — perhaps for several hours.

This time allowed us to use a notebook system to monitor the storm on weather-related sites, keep in touch family, and even watch live streaming video from local TV stations. Although the UPS conked out several hours before the power came back, it was nice (and immensely useful) while it lasted.With your broadband connection and home network up and running courtesy of battery power, you can remain connected and productive for quite a while during an extended power failure. I experienced this firsthand a couple of years ago when Hurricane Wilma rolled through Southwest Florida. It wasn’t long after the storm arrived that our power went out, but thanks to a UPS powering my cable modem and wireless router, the Internet access and the wireless network remained up for almost two hours.

Of course, power failures can be caused by myriad reasons other than hurricanes, so wouldn’t it be nice to know your Internet access can continue humming along for a time after the power goes out?

The best way to ensure this is to plug your broadband gateway and router into their own dedicated UPS device. This way, they won’t have to compete with more ravenous devices for limited battery power. If you absolutely need to share a UPS device with a desktop system, make sure it also connects to the desktop via USB and is running software to automatically shut the system down (or do it manually yourself as soon as the power fails).

When setting up a UPS, be mindful of which of its outlets you’re using, because some outlets provide only surge suppression and not battery backup. Needless to say — but I’ll say it anyway — avoid plugging nonessential devices like printers into battery-backed outlets.

No Magic Formula
This is the point where I’d love to provide a universal mathematical formula for calculating UPS runtime based on a power consumption, but there are so many variables to consider that there’s no way to provide one with any accuracy. (Be wary when researching this topic on the Internet, because there’s lots of misleading and contradictory information out there.) Your best bet is to find the power consumption of your gateway and router — often expressed in watts — on their power supplies (mine added up to a total of 30 watts, which should be pretty typical) and then check the UPS manufacturer’s web site for an estimated runtime chart for a particular model you’re interested in.

For example, the following chart indicates that an $80 APC BE650R will run for about an hour-and-a-half under a 50 watt load, and a conservative extrapolation suggests that it should easily last two hours when providing just 30 watts. You may notice from this chart that UPS run times generally aren’t linear (i.e., compared to full-load, a UPS at half-load will usually last not twice as long, but often three, four or five times longer).

One final caveat — even when your gateway and router are connected to a UPS, having Internet access during a power failure will ultimately depend on one variable that’s out of your control: namely, whether your cable or phone company’s remote location also has a battery backup (or generator) to keep its own equipment running during a power outage. Although this is usually the case, there’s no guarantee, so if during a blackout your devices are powered but you still can’t get to the Internet, it’s probably because there’s no power on the other end.

Joe Moran is a regular contributor to PracticallyNetworked.