Battery Backup Power - Here's What You Need to Know

Category: Hardware

A concerned reader asks: 'Can you recommend a backup power supply for computers? During the last storm, my PC crashed and we lost power for several hours. If I had a battery backup, I could have saved the document I was typing, and gotten online to check for email and weather updates. I've read about Uninterruptible Power Supply units - is that 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, I do recommend that you get 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. If you live in an area where the lights sometimes flicker, or the power drops for just a second a comes right back, your computer could be damaged. Protections against these types of electrical power hazards should be part of your UPS.

UPS battery backup

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 standby or 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 backup 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. Plug in the devices you have (desktop, laptop, monitor, and peripherals) and it will estimate the power needed to keep them running, and give suggestions for APC products that will do the job.

One of the most popular consumer-level UPS models is the APC Back-UPS 600VA ($60) which provides battery backup and surge protection for your home computer, router, and peripherals. It has 7 total outlets (5 provide both battery backup and surge protection; 2 offer surge protection only). There's also a USB charging port for your smartphone or tablet. APC says the battery in this model should last 3-5 years, and are replaceable. This model gives you about 25 minutes of battery backup with a 100-watt load. That's 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.

The APC 1500VA Back-UPS Pro ($165) is a significant step up. It has 10 outlets, and will keep your gear powered up (100-watt load) for 68 minutes. A display on the unit will tell you how many watts are in use, and the amount of battery time remaining.

Another popular UPS model to consider is the CyberPower 900VA ($99). It offers 6 battery backup & surge protected outlets, and 6 surge protected outlets. Data line protection prevents power surges that travel through telephone, coaxial and ethernet lines. CyberPower has a 3-year warranty, including the replaceable battery.

The Tripp Lite 1500VA ($171) is also highly rated, and provides up to 90 minutes of runtime for an entry level PC system. Includes user-replaceable batteries, software to enable unattended system shutdown, and 3-year warranty.

Amazon Basics also has a lineup of Standby UPS models, ranging from 400VA ($39.99), to 600VA ($59.99), to 800VA ($82.99).

Don't Forget About Your Internet and Phone and TV

During a storm or other hazard, it's quite possible that the electrical supply lines might be down, but the telephone, cable or fiber optic lines are just fine. A battery backup unit can power your landline phone's base unit, as well the modem/router for your Internet connection. Some internet service providers install an interface box with a battery backup unit. When I had Verizon FIOS service, that battery would only last about 15 minutes. So during power failures, I plugged the FIOS battery backup into a UPS so I could continue to make phone calls and exchange electrons with the Interwebs. For outages longer than a half-hour or so, a gas-powered generator will be necessary.

I've found that purchasing a gas-powered generator is a great way to ensure that you'll never need one. In 2012, Hurricane Sandy heavily damaged the power infrastructure in my area, resulting in outages that lasted for several days. The year before, Hurricane Irene also knocked out power. I assumed that we'd be seeing more of the same, so I purchased a beefy gas-powered generator. But in the past eight years, we've had no outages lasting more than a few minutes. Your mileage may vary. :-)

It's important to conserve every watt of power when running from backup power. So if you have your computer and other gear connected to a UPS, I recommend turning off the printer, speakers, external hard drives and other non-essential items unless you're actually using them. I have a dual-monitor setup, so I power one of them down, too. Laptops and tablets use a lot less power than desktop rigs, so consider moving to a smaller screen when running on auxiliary power.

But I Already Have a UPS...

I had a Tripp-Lite TE-600 UPS for many years, and there were 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 when the internal batteries died of old age. Fortunately, I only lost the document I was working on, and I've since replaced that unit with a beefier model that'll run my desktop appliances for at least 30 minutes.

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! I found a good deal on a $12 battery from BatterySharks but the shipping cost added another $10. You might want to shop locally when purchasing a UPS or replacement batteries.

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

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Most recent comments on "Battery Backup Power - Here's What You Need to Know"

(See all 29 comments for this article.)

Posted by:

12 May 2020

For many years I've had two of the APC products and never had a problem. I don't remember right off the bat which models they are, but they provide an hour or so of battery backup. It's fun when the neighborhood is all blacked out and we can still sit here and watch TV. I've got another of the same model for my computer. We also have the backup system for our FiOS system that was installed by Verizon. It's been here many years and never had a problem!

Posted by:

Wild Bill
12 May 2020

Sarah, while you may not NEED a UPS, there is no reason I can think of why your house wiring or its vintage would make one of no benefit. The UPS will keep you running for a bit when any power interruption occurs, whether from home wiring issues or loss of utility power due to whatever reason. The only reason you might not benefit is if you do not do anything that cannot be easily redone or seldom have your computer on, especially in bad weather. Or if you use a laptop, which contains a battery of its own and thus has a built-in UPS.

Posted by:

12 May 2020

I've used APC backup power supplies for years. Never had a problem with them (although when I tried a different brand I had a problem with that!) and am currently using a 1500 with my PC. The APC units have saved the day for me on many occasions. And no, I don't work for them, but I will recommend their products from now till doomsday because they've done the job consistently.

Posted by:

12 May 2020

I too cannot imagine why the age of the house wiring should matter. We live in a house that was built in 1953 and it has never been a problem. Mind you, the service panel has been upgraded twice and we have a number of circuits that were added later. We also have a UPS that backs up the settings for the PVR but nothing for our computers because they are both laptops.

Posted by:

12 May 2020

It would really be nice if there was a way to check the health of your UPS battery periodically, and then--based on the health check--replace it before it goes dead, yet not so early (trying to predict its life) that you waste money by too-early/too-frequent replacements. I have a gizmo that plugs into my car's cigarette lighter and it gives me info about the battery and its charge. It would be cool to have a tester sort of like this that you could just plug into the unplugged UPS and get an idea about the UPS's battery. Does something like this already exist? You could use a voltmeter, but interpretation of the readout may be tricky.

Posted by:

Dave Blevins
12 May 2020

Don't forget other "smart" devices such as expensive sewing machines (probably computer driven)

Posted by:

12 May 2020

These UPS have replaceable batteries but surge protector needs replacement every few years anyway (due to MOV -metal oxide varistor - degration). So UPS needs to be replaced every few years?

Posted by:

Frank Cizek
12 May 2020

I'm on my 2nd APC 660 unit & will never be without one!
Re: "It would really be nice if there was a way to check the health of your UPS battery periodically,..." I'd be interested in the answer to that question, too!

Posted by:

12 May 2020

Re "It would really be nice if there was a way to check the health of your UPS battery periodically": On my unit there is a display which shows the strength of the battery. The software should check that too, but sometimes that has glitches. When I start noticing the battery life indicator going seriously down (which I didn't think to do last time!), I'm going to treat it like I treat my gas gauge - fill 'er up, i.e., get a new battery and replace the existing one.

Posted by:

12 May 2020

Two comments for previous responders:
Sarah - as long as the wiring in your house is up to code, and you have 3-prong (grounded) outlets, go ahead and get that UPS. If you do not have grounded outlets, my advice would be to spend your money to update your wiring, and then get the UPS.
Nigel (and everyone) - Try to recycle UPS batteries at your local auto parts store. They take them in my area, and it seems likely it would be the same nation-wide.

Posted by:

12 May 2020

A stand-by generator may still require a UPS. There may is a generator startup period and a switchover from street power to generator power lag which can be approximately one minute. Our Generac generator does not supply power fast enough to prevent the computer from shutting down.

Posted by:

12 May 2020

Been using APC products forever. I have two so that everything is plugged in. When one bites the dust, I drive over to Staples and get a new one. It's a must-have, especially for desktop users.
APC battery Back-UPS, 9 outlets (6 for battery, 3 for surge) $100
They last three or four years.

Posted by:

Robert A.
13 May 2020

I happen to live in an area that has a retail chain called Batteries+Bulbs, which, I believe, is a franchise operation, and sells exactly what their name implies - batteries and light bulbs. This firm sells all sorts of batteries for cars, trucks, hi-lows down to your basic alkaline AAs, AAAs and 9 volt types. They carry a huge selection of batteries that will fit most UPS boxes.

The store near my home also will remove and install UPS batteries, as they have a tech bench in the back of the store, where the guys there can do a swap-out in about 15 minutes, or so. Since the store is a very specialized retailer, they usually only have a few customers inside at any one time, and can offer service very quickly.

The replacement batteries generally cost between 20 to 50 dollars, each, depending on the quantity, physical size and amperage capability that your box needs. I've had the batteries in my once APC 1000 unit replaced twice, from B+B, and my now APC 1500 works just fine, without any issues, for about half the price of a new tower, including a size upgrade, than those sold at Costco, Sam's Club or Best Buy.

A FYI handy tip is that APC and Cyber Power towers are usually sold in three to four power sizes such as 800, 1000 ,1200 and, maybe 1500 VA ratings. but the several models from the same manufacturer often use the same tower box, with just different labels to indicate the power rating. When replacing the UPS batteries, one can actually "move up" in VA ratings. from, say, a 1000 VA to a 1500 VA, by buying a larger capacity battery/batteries, for, usually, just a few dollars more, which will fit into the UPS tower, perfectly, and will allow a somewhat longer run time than the batteries of a lower VA rating.

Regarding homes that have whole-house generator systems, that switch the power over to the unit when the local power utility feed dies during a severe storm, one would still need to have a UPC unit hooked up to one's computer(s), because, as stated above, by Bobo, it can take anywhere from 10 to 30 seconds for the generator to start up and the transfer switch to kick in and begin feeding the house with juice for the generator.

I have a 35 KW Kohler unit that can pretty much keep my whole hose running - lights, HVAC, refrigeration, etc., but, just to keep my TVs, cable and video recorder boxes running without fail, I have those items plugged into a smaller capacity UPS unit, about 600 VA, to maintain power during the brief switchover.

Even with the lights going out for a few seconds, I am still able to watch TV, albeit, in the dark, until the Kohler unit is up and running.

Posted by:

David Horsfall
13 May 2020

My position in Spain is pretty similar to that of Bob H above. I have four UPS units in constant use and also a diesel generator. However I did find that one UPS was useless when supporting two NAS units. Couldn't understand why....the unit was quite expensive and had a new battery. Every time the power failed momentarily, the NAS units objected and took hours to sort themselves out. We found out that could be solved by have one UPS per NAS which was unfortunate & not mentioned in any manuals. I've found that many people give them up when they find the unit no longer works as expected when the batteries get older. So more time, cost and vigilance is needed to run the darned things.

Posted by:

Mike Nease
13 May 2020

Sarah, Converting your older model house to a three-wire grounded system can be quite expensive as you can imagine as all the wiring inside the walls must be replaced. There is another solution that provides surge protection. There is still some cost involved, but nowhere near the cost of rewiring your whole house. Most utilities can provide you with whole-house surge protection by installing a protection unit at your meter. This has the added advantage of protecting all electronics within the house. You can contact your local utility for cost and availability.

Posted by:

Steve B
14 May 2020

The easiest way I can think of to test the battery in your UPS is to have the computer turned on, but not running any critical apps. Then simply unplug the UPS from the wall. If the battery is in good shape, the computer will remain operating for however long the VA rating of the UPS allows. If the battery is bad or failing then the computer will crash in a very short time. BTW, your monitor is probably the biggest drain on the UPS of all the components in your system. Rate your UPS by how long you want the monitor to stay alive after house power has failed.

Posted by:

14 May 2020

Had two of the big APC 1500 and both started flashing the F04 death message their second year.

I don't spend this kind of money to have to start diagnosing their stuff, making calls, getting replacements and all that hassle. Not at all impressed with their software either. This was on new, maintained, updated and bug free computers.

Going with Cyber Power next time and just deal with the limited powered shutdown time.

Posted by:

Phillip Jeck
15 May 2020

I have a genarac 20 KW natural gas generator for my house. It powers both air conditioners 2 refrigs, a freezer, and everything else in the house. It test it self every Sat. at noon. I have APC UPS on all five tv's amd two computers. None of the electronics ever blink. Been running this way for over 10 years, Have had to replace some of the UPS after 5 - 6 years, could have probably saved some by replacing the Batt's. Just had a APC 1500 AC screen go bad, I had purchased a Square Trade warr. and they had me send it to them at their cost, and sent back it could not be fixed and were sending me a check. I will buy another this week. UPS is the only way to go.

Posted by:

18 Mar 2021

Choosing an UPS inverter is a tough and complex task. I used Power Calculator by MSP Web Store and it helped me a lot in selecting correct UPS inverter for my home

Posted by:

22 Feb 2024

I want to emphasize what a few commenters have said. You can get whole house surge protectors which go on the main electrical panel. I can't remember what ours cost but it wasn't enough to break the bank. Considering that most of us have several electronic devices besides computers that could be damaged by a power surge, it would be money well spent.

And about the two-wire house, my house is a two-wire house. Some years ago, the provincial regulator decided that GFI's could be used in two-wire houses so we had them installed on the most important sockets. Anyone who would like to have GFI's in a two-wire house should consult a licenced electrician to find out what is allowed where you live. (I live in Ontario, Canada.)

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