Computer Backup Power

Category: Hardware

What do you recommend as a backup power supply for computers? During the last storm, we lost power for several hours. If I had a battery backup, I could have gotten online to check email and weather updates. Is an 'uninterruptible power supply' what I need?

What Kind of Backup Power Do You Need?

A sudden loss of electrical power can cause your computer to shut down or reboot. Of course, you will lose anything you were working on at the time of the power glitch. But power failures can also cause head crashes in hard drives, which can damage a disk and the data on it. To guard against power failures, get yourself an uninterruptible power supply (UPS) to provide a backup power source for your computer.

A UPS, at its core, is a battery backup power supply. It includes circuitry that instantly switches from line power to battery power in the event of a power outage. The simplest and cheapest type of UPS, called a standby UPS, does nothing more. But power outages are not the only hazards your computer faces.

Fluctuations in line power quality are much more common than blackouts. A voltage spike or its opposite, a voltage drop, can adversely affect your equipment's performance and lifespan. Protections against this type of electrical power hazard should be part of your UPS.
UPS battery backup power supply

A line-interactive UPS is also relatively inexpensive; it filters and conditions line power as well as providing battery backup. An on-line UPS provides the highest quality line power and the greatest protection against power outages. Most home computer setups require no more than a line-interactive UPS.

What Features Do You Need in a UPS?

A UPS may include other features as well. Monitoring ports on a UPS can tell attached equipment to shut down gracefully in the event of a power outage, in case no one is around to shut things down manually. Fax and modem telephone-style outlets may be provided on a UPS to give these devices surge protection. Some unprotected power outlets may exist for printers and other devices that do not need battery power but should be protected against power fluctuations.

The capacity of a UPS is measured in volt-amperes (VA). How much capacity you need in a UPS is a function of the power needs of all the components you wish to protect and the amount of time that you want to be able to run on battery power. APC, a major UPS manufacturer, has a handy calculator that can help you determine what the capacity of your next UPS should be.

One of the most popular consumer-level UPS models is the $59 APC Back-UPS ES 550, which provides battery backup and surge protection for home computers, and your phone/fax/modem/DSL line. Automatic system shutdown software is included. This model gives you just a little over 3 minutes of battery backup - enough time to save your work and shutdown, but not a good solution if you want to stay up and running during a longer power outage. Other top brands include Tripp Lite, Eaton, Liebert, CyberPower, and Minuteman.

But I Already Have a UPS...

I've had a UPS for ten years, and there have been many times when the lights flickered in the house, causing televisions and alarm clocks to shut off or reset. My computer never even flinched. Even during power outages, my trusty computer plugged away, while the rest of the house was dark. But during the winds that Hurricane Irene brought to my area, we lost power and my UPS failed me. Fortunately, I only lost the document I was working on.

A UPS contains a battery, of course; typically, a lead-acid battery much like the one in your car. Such batteries are generally good for several years, but eventually they do need to be replaced. UPS units and replacement batteries are available online, but pay close attention to shipping charges; these things are heavy and expensive to ship! It may be a better idea to shop locally, when purchasing a UPS.

Do you have a battery backup UPS? Post your comment or question below...

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Most recent comments on "Computer Backup Power "

(See all 23 comments for this article.)

Posted by:

Dr. Keshav Sharma
03 Oct 2011

Nice article. I have a number of small UPSs and also one big online and one big offline UPS for my laptops, desktops and other electronic equipment. I have seen many persons not using a good UPS for powering their desktops and some of them have lost data as well as some electronic part. I use one UPS for my laptop (this may seem to be an overkill) and a surge protector. My laptop is going strong and I find no power problem. Even sometimes I remove the battery and place it in my fridge and use UPS power only.

I agree that APC UPSs are the best and I have a number of them in my home.In India there are other good companies manufacturing good power equipment.


Posted by:

marvin alper
03 Oct 2011

How do you determine that the battery nees replacement?

Posted by:

03 Oct 2011

I live in an area of the Chicago region where we have frequent power outages, and power fluctuations. I have used APC UPS for 12 years now and it has never failed me. Usually during the summer is when I experience most power problems, however a windy winter seems to make the electricity go crazy too.

In all cases, my UPS has saved my computer. In the event of a power outage, I am able to safely power down my computer. One cool feature of my UPS is the ability to shutdown automatically in the event I am not around when the power goes out. In most cases it will automatically save any work I had open on various programs so I do not lose anything.

In addition it has a nice power management feature, if my pc becomes idle for 2 hours, my UPS will automatically power down, and turn off any devices currently using wattage (printers, external hd, speakers, etc).

If you live in an area with frequent power interuptions, I highly recommend a UPS.

Posted by:

Jay Gerard
03 Oct 2011

I've also used a UPS for many years. Just replaced one model CyberPower with another CyberPower model. When the first model failed to prevent power-induced reboot, I contacted their support staff. Turns out the model I had produced a simulated sine wave, and my Dell requires a pure sine wave! Talk about w-a-a-y out info. So I'm curious as to why your UPS failed. Something to teach me, perhaps. Thanks. I enjoy your articles very much.

Posted by:

03 Oct 2011

A UPS is a great investment...for all the reasons Bob mentioned and don't be afraid to get a little more than you need. In this case more is better. I have a UPS on all my electronics (TV, Home theater, CD/DVD players, my home wireless network, etc.) You don't need a UPS for printers (although if you have the cash go for it) but surge protection is recommended.

Posted by:

03 Oct 2011

I have a geek squad power back up, it beeps but power goes right out on my comp. Seem to have a lot of power outages, here. On main city street, in city, too. Dont matter if bad weather or not.
I think they just want us to buy their, protection generators.
Thks Bob, I love all your newsletters.

Posted by:

03 Oct 2011

I'm a huge fan of UPS'. They're not just for computers, though.

In the den my TV, theatre amp/stereo, Wii, and cable box are on an APC SmartUPS 1400 and there's an APC SmartUPS 1000 tucked between the recliners for laptops and cordless phone base.

Upstairs, the cable/VOIP modem, bastion host, wireless AP, switches and monitors, speakerphone, etc. are on another APC SmartUPS 1400 with monitoring and automatic shutdown and restart on power restore. Each desk in the home office has its own APC 1000VA UPS as well.

Several times in hurricane season we've just kept watching Netflix and surfing the web when the neighborhood's gone dark--both DSL and cable typically keep running during outages.

Best part is, I have bought each for $1-$5 at local thrift stores. Folks seem to just throw them away rather than replace the batteries.

Posted by:

Nat Gildersleeve
03 Oct 2011

Please see my note above. That is the way UPS/Computer behaved until I changed to a pure sine wave UPS.

Posted by:

Wendell Rothgeb
04 Oct 2011

Yes, the UPS is great to have but during power outages it will not keep your computer running indefinitely unless you get one of the big commercial units at a humongous price. Most are designed to give you a shutdown time while the power is out. If you use a modem and the power goes so goes your modem because the modem is supplied by local power. The modem is what gives you the internet connection even though the ISP area may not be affected by the power outage. How do you know when the battery needs replacement? Most UPS units come with a cable that ties into the UPS and your computer plus a software disk. Once the software is loaded on your computer it monitors the voltage and gives a warning when the battery is low. The UPS unit has a charging circuit inside and when the battery gets into such a low state and will no longer charge the software will tell you. Read the UPS instructions thoroughly and you will be OK. Hope this answers some questions.

Posted by:

Herb McChesney
04 Oct 2011

Who sells affordable UPSs with a true sine wave output? My PC power supply requires this.

Posted by:

Mike Budwey
04 Oct 2011

You added an editors note to my earlier comment about the OP's ISP could very well be operational in a power failure.

I know for a fact that with my FIOS setup, the interface box (where the fiber enters the house) has an internal battery that keeps the internet alive for only 15 minutes. (It keeps the phone line up for about 2 hours with a 15 minute emergency reserve at the push of a button.) So, unless I ame willing to modify the interface box, I'll have only 15 minutes of internet connectivity in a power failure.

I would imagine (but don't know for certain) that cable providers have a similar setup. DSL may be more likely to work, but keep in mind that any routers or switches will also need to be powered by the UPS.

Posted by:

04 Oct 2011

To marvin alper:

My APC UPS comes with optional software you can install (or just use MS power management in control panel), and the expected life period of your battery is approximately 3 years (depending on usage). I have never upgraded my UPS because of an aging battery, I have upgraded due to the power requirements of my PC. APC has a decent calculator on their website which can help you select an appropriate model.

Posted by:

04 Oct 2011

In the past APC's pure sinewave UPS's were pretty pricey. I found one that fit my needs for a lot cheaper from Cyberpower. I bought a Cyberpower PT1500T.

Posted by:

05 Oct 2011

A UPS is fine as far as it goes. I live in a rural area and have had many power outages lasting several hours and even (in one case) almost 2 days. I have a generator to run such equipment as my pellet stove (for heat) the refrigerator and microwave. It will power my TV, DVD player, computer and some lights too.

However ... since I have cable for TV and internet, and the cable runs above ground with the power lines, it usually goes out with the electricity. I rarely have TV and internet when the power is out. If you live in an area like mine, don't count on your cable staying on when the power is out.

Posted by:

12 Oct 2011

I have had the APC Back-UPS ES 350 for 6 years. My deaktop, router, printers, etc have been attached. We live on a mountain in a remote corner of Cherokee County Alabama where we have frequent fluctuations UP and DOWN, and then some complete outages...from 2 secs to 2 hours! In March 2011, on a beautiful clear day, we had a power outage for exactly 1 hour. When it came back, my (older 2004 HP w/XP) PC would not boot up Windows. I lost everything, all data, lots of family photos, etc! (I now have a 2 TB ext hard drive as backup!!) But I'm guessing my UPS was not working properly then. I should have tested it earlier. Then came the 2011 Alabama tornados, we were without power for 4 days, even up here in the remote corner of the state. What a learning experience for both maintaining "back-ups" and providing some temporary power sources, like a working UPS!!

Posted by:

22 Jun 2012

I replaced my APC UPS last year when it begin squealing all the time, but I think that was the signal it just needed a new battery.

I gives the user time to close all work and gracefully shut down (be sure the cable modem and network get power), but I hesitate to do anything else after the power fails.

Posted by:

22 Jun 2012

I have found that not only are replacement batteries heavy, they cost almost the same as a new UPS unit.

Posted by:

23 Jun 2012

An easy way to load test any ups is to first determine the wattage of your load (you can use the nameplate rating on your devices) then substitute a table lamp in place of the load equipment, with a lamp of similar wattage. When the lamp dims or the low power alert sounds, you have the max run time. Figure to use no more than 2/3rds of the time, to allow for a reserve.
A bad battery will die very quickly, often in seconds.

Posted by:

23 Jun 2012

I suggest Bob Rankin writes an article on 'Connecting a car battery to a UPS'
There is a lot to look into. One that comes to mind is the charging circuit within the UPS. If that is taken care of, I should think one would get a lot more HOURS of operation. But I haven't ever found the time to investigate this. If a car battery is hooked up to the UPS without any modifications to the internal circuitry, there is a chance that the battery would fail prematurely.

Posted by:

24 Jun 2012

I have a Cyberpower UPS that doesn't work. I changed the battery in it a few months ago and, as before, when the power goes off, my computer instantly does a hard shut down. So, for me, a ups is a waste of time and money.

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