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Practical Computer Advice
from Martin Kadansky

Volume 8 Issue 8
August 2014
The Top Three Things You Should Know About Uninterruptible Power Supplies (UPS)

Has this ever happened to you?
  • You're working on your computer and suddenly the power goes out. Your computer turns off and your screen turns black, and now you wish you had clicked Save more often while you were editing that important document or email.
  • Your power goes out, but your laptop or tablet continues to operate from its internal battery. However, all of your other devices are off and you wish that some of them would stay on for a little while, like your internet connection or your landline (or cordless) phone.
You may not know what causes any particular power outage, especially if they're infrequent. They might be due to circumstances in your town or neighborhood (equipment failure or construction), or be more likely during hot summers (more power consumption due to air conditioners and fans) or freezing winters or storms (ice and snow and wind bringing down trees and power lines).

What's a UPS?
If you're concerned about power failures, especially if you've lost work on your computer due to power outages in the past, you should buy (and properly set up) a consumer-level "uninterruptible power supply" or "battery backup" unit. A UPS combines a surge suppressor with a big battery, and has special circuitry that detects a power failure and quickly switches over to run your equipment on its battery.

Why would I get a UPS?
The sole purpose of a UPS is to give you a few minutes at the start of a power failure to do two things:
  • Save your work, and
  • Shut down your computer.
A UPS is not designed to let you continue to use your computer for hours and hours until the power comes back on. If properly chosen, a UPS will give you 5 to 10 minutes (possibly more) to Save and do an orderly Shutdown.

What should you look for in a UPS?
I've had good (not perfect) experiences with UPS units from APC (American Power Conversion Corporation), and I've also heard good things about other brands like Tripp Lite and CyberPower. Choosing the right UPS starts with adding up the power requirements, in Watts, of the equipment you want to power during an outage, choosing a unit that supplies at least that much power, and making sure you plug the UPS directly into a properly wired and grounded 3-prong power outlet (with no additional surge suppressor or extension cord).

However, your situation may include additional factors not covered here, so I suggest reading more about this online, or talking directly to APC or a good computer consultant or electrician. Expect to spend somewhere between $50 and $150, depending on your needs.

That's it. You now know the most important things about UPS units. You can stop here if that's all you want, or read on for my more detailed advice.

Should you get a UPS for your computer?
The key questions to ask yourself are:
  • If the power goes out, will that also turn off my computer (which will in turn discard my unsaved changes)?
  • If that happens and I didn't have a chance to Save my work, am I concerned about losing whatever I was working on?
If you have no concerns about losing data in the event of a power failure, then there is no point in your going to the time and expense (both short-term and long-term) of buying a UPS and maintaining it.

However, if this does concern you, here are some things to consider:
  • If you have a desktop computer (for example, a Windows "tower" or "minitower," or an iMac or PowerMac) which does not have an internal battery, then a power failure will immediately turn off your computer.
  • If you have a laptop with a working internal battery (i.e., one that still holds a charge), a power failure will simply make your laptop switch over to run on its own battery. This almost entirely eliminates the risk of losing data (with the exception of data you may be editing online), assuming that your battery is charged, and you are present to notice that the power went out and click Save.
  • Also, if you have set up your laptop to use important peripherals that need their own power (like using an external monitor with the laptop lid closed), while you won't immediately lose your work, you may not be able to fully operate the laptop during a power failure (and Save your work) until you disconnect those peripherals (and open the laptop's lid).
  • And if your laptop's internal battery is more than 3-4 years old, it's more likely that it no longer holds a charge, so a power failure will either immediately turn it off, or you may only have a very short time on the battery to react before it powers off.
If these issues concern you, you should probably buy a UPS.

Should you get another UPS for other devices besides your computer?
Ask yourself:
  • Beyond my computer, are there other powered devices that I also want to keep using for a few minutes during a power failure?
For example:
  • Do you do a lot of work online that might get lost during a power failure? If so, you could put your cable or DSL internet modem and router on a UPS which (assuming your ISP is still functioning during the outage) would give you a few more minutes of online time to save your work. (This is known as "internet by candlelight.") If you also use a VoIP phone (voice over IP telephone interface, e.g., your "Vonage box"), you could put that on a UPS as well.
  • Does your landline (or cordless) phone base unit need power to operate? Putting it on a UPS would give you a few minutes to make an emergency call or two, assuming your phone service was still active during the outage.
  • Would losing power to your cable TV box (or DVR, VCR, etc.) create a big inconvenience when power is restored (e.g., waiting hours for it to download your TV schedule)? Put it (or any low-power device where losing power will be inconvenient or annoying) on a UPS and hopefully save yourself that trouble.
  • While keeping a battery-powered flashlight nearby is best, consider putting your desk lamp on the UPS to provide a little emergency lighting.
What you should know about setting up a UPS
Setting up a UPS usually involves the following:
  • Connecting the battery wires
  • Plugging the UPS directly into a properly wired and grounded 3-prong power outlet (with no additional surge suppressor or extension cord)
  • Deciding which critically important devices to plug into the "battery" outlets, so they'll get power during an outage: Computer, external monitor, USB hub, external hard drives, etc. Just remember that the more devices you plug into the battery outlets, the fewer minutes of operation you'll have during a power failure. If you also want to power your modem, router, phone, lamp, or other equipment, depending on the additional wattage, consider getting a separate UPS for them.
  • Deciding which non-critical devices to put into the "surge protected" outlets (and won't be powered during an outage): Printer, scanner, speakers, cell phone charger, etc.
  • It may sound counterintuitive, but don't plug the UPS into an extension cord, a surge suppressor, or a surge suppressor into the UPS (or a surge suppressor into another surge suppressor). My research indicates that daisy-chaining surge suppressors may decrease the response time of the surge suppression, increasing the risk of damage to your equipment from power surges.
  • Just as you would with a power strip or surge suppressor, don't plug in more equipment (amperage) than your power circuit can handle. Some units can also surge-suppress a telephone line and a coaxial (cable TV/internet) connection.
  • The UPS may also include software and a special cable that can put an alert on your computer screen when the power goes out, and if you don't respond within a few minutes, it will shut down your computer in an orderly fashion. The software can also let you adjust the UPS' settings and see how many estimated minutes of "run time" you'll get, the health of the battery, etc.
What you should know about using a UPS
Here are the important things you should know about using a UPS, based on my experience with APC units:
  • A UPS draws a little power all the time to keep its battery charged.
  • When the power goes out and it switches over to battery power, your UPS will beep loudly every 30 seconds. This is your cue to save your work and do a Shutdown right away. It can also be disconcerting if this happens in the middle of the night.
  • Using the software and special cable, you can adjust when the beeping occurs (for example, not to beep during the night), but I don't recommend turning it off entirely.
  • The battery will wear out and need to be replaced about every 3 years, and it will show a red light and make a "chirping" sound to let you know. Since it's probably a lead-acid battery, you should dispose of it properly. If you buy a new battery directly from APC, if you're in the US you can mail back the old battery for free.
  • The UPS unit itself will wear out and need to be replaced about every 4-5 years.
Additional things to consider
  • Weight: In part because they usually use lead-acid batteries, UPS units are heavy. Mine weighs about 19 pounds.
  • Battery-powered devices: A UPS won't help directly with tablets, smartphones, etc. It can help indirectly if you put your internet modem and router on a UPS. Also, after turning off your computer, in an emergency you could plug your cell phone charger into a battery outlet of your UPS to charge up your phone, but I wouldn't leave your charger plugged into the UPS all the time.
  • Brown-outs vs. power failures: If you experience frequent voltage drops or "brown-outs" (instead of complete power outages) you may also need a power line conditioner or an automatic voltage regulator (AVR), both of which are beyond the scope of this discussion. If you're shopping for a UPS you might look for additional features like these, but I also suggest talking to your local power company.
  • Computer damage: While you may lose your unsaved changes to a document or email, power failures usually don't damage your computer, so you're not likely to lose your existing (already-saved) data. In any case, you should also have a thorough, scheduled backup system for your computer just in case.
  • Save early, Save often: Some programs (like Microsoft Word, Excel, PowerPoint) have features (like "autorecovery") that can help recover your unsaved document changes in the event of a power failure or computer crash. A UPS can also help, but you can avoid such problems entirely if you simply get into the habit of clicking Save, especially before you step away from your computer.
  • Should you unplug your equipment? What about lightning? I don't think there's anything wrong with unplugging your equipment, and doing so will certainly isolate it from surges. As I wrote in my newsletter last month, lightning can randomly destroy your equipment whether it's plugged in or not. Thus, only you can decide whether the inconvenience of unplugging reduces your risk enough to be worth the trouble.
  • You should buy a separate UPS for each computer.
  • Keep a flashlight and spare batteries handy.
Where to go from here
How to contact me:
email: martin@kadansky.com
phone: (617) 484-6657
web: http://www.kadansky.com

On a regular basis I write about real issues faced by typical computer users. To subscribe to this newsletter, please send an email to martin@kadansky.com and I'll add you to the list, or visit http://www.kadansky.com/newsletter

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I love helping people learn how to use their computers better! Like a "computer driving instructor," I work 1-on-1 with small business owners and individuals to help them find a more productive and successful relationship with their computers and other high-tech gadgets.

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