by   May 01 2012   
When you start shopping for your new computer and it's not a laptop with a battery you might also take some sound advice and calculate the type of backup power supply you will need. Unless you never experience brownouts, blackouts or complete power grid failures for hours, days or weeks then this wouldn't apply to you. But, wait, what about spikes, surges and dirty power sources? Now it applies to everyone.

Backup Power Supplies, UPS Equipment

Power outage leaving your computer in the dark? Learn how to select your backup power

We have people asking what type of power backup system they need for equipment after the storm has hit. And many that have power backups say it does not last long. Here is a simple guide to make your backup work for you.

Top Searched Questions and Asked Questions:

  1. Will a UPS run on a modified sinewave inverter?
    1. Technically No, a quality UPS will identify a modified sinewave as dirty power source and will switch over to battery power every time.
    2. This also is the same for generators that are not designed for electronics.
    3. Just say NO to DIRTY Power sources and your equipment will live longer.
  2. Can I run my Computer from any inverter?
    1. In most cases yes, but be warned, newer equipment might not last very long running on a bad power source. This goes back nearly 20 years when backup switching power sources were replaced with UPS which is uninterrupted power supply. That means when you have your computer connected to your UPS it is only taking regulated pure sinewave power. It's the cleanest power you're going to get and it will make your equipment last for years and run cooler even.
    2. Connect a dirty power source (spikes, dips, overvoltages, static) you'll be pushing your equipment which doesn't filter power and regulates to a degree.
    3. Remember, your computer might run from a dirty power source but your UPS will not charge from that type of source.

Because this is the time of year everyone looks for the perfect solutions to the hours, days, weeks of no power I'll start a section about some serious emergency power backup systems that are more homemade than commercial due to the costs.

If you search "Modify APS UPS for 18+ hours" you'll find a electronics group that really pushes things to the limits. I would suggest if you do any modifications to your UPS keep them external modifications only. Add cooling fans when you push the hours past 2 under 40% load. If you need 80% load be sure you have some cool air flowing.

I'll get into the electronics more in another post. I'm guessing some of you might really need to keep your systems running.

  1. Do Laptops charge with Modified Sinewave inverters, YES. You might even get it to charge with just about any type of inverter. I'd recommend at least a modified sinewave which might keep your AC adapter cooler or at least lasting longer. Your AC adapter has a wattage rating on it, go above by 20% and you'll be fine. I run 50% or higher on all UPS which means if my laptop requires 100 watts of power I get an inverter of at least 200W. The idea is to keep things running longer and cooler.

Car Alternators and your Stair Climber, I'll dig up my modification to a standard car alternator to see how fast you have to make your stair climber go to get a good charge output. You never know, power outages could be healthy and you'll still have your Google+ fix!

When the power goes out and you need to keep working you have 2 configuration choices.

  1. Backup Computer System Only
  2. Backup Computer System and Network

Most people choose to backup only their computer system but for those that need to stay connected we need to make sure your cable modem, DSL modem, network router and network switches are all powered during a power outage.

We we design a power backup system we first take a look at the peak watt draw of each piece of equipment that will be connected to the battery backup.

Terms to understand before we go on.

  • Battery backup. This is a switching backup you can think of it as a light switch. When the unit detects the power outage it will switch over to the battery side and start running. This works OK for radios and printers but not computers and newer electronics like your HDTV. You don't see many of these on the market because of the time delay they have when they switch over to battery power.
  • UPS (Uninterrupted Power Supply) the UPS is normally the best choice in that your equipment runs off the UPS full time so when the power goes off their is no switching from current to battery time. Hence the word Uninterrupted power supply. Highly recommended.

We are going to talk only about UPS backup systems due to the 3 protective stages they offer.

  • Brown Out or Low Power (When your power drops below 105 volts on average the UPS will kick in and maintain the 110vac that you need.
  • Black Out or Power Outage (When the power drops to 0vac the UPS is full-time battery at that point)
  • Power Flux or Surge: The UPS filters the power so your equipment does have over or under voltage.
  • Dirty Power Source: I'll try this example: It's like a hum on the line that you can see with an oscilloscope but can't hear or see with your eyes. Electronics that have internal clocks and other components that need to read the Hz (Hertz) to operate might have problems with dirty power sources.

To determine what size of UPS we need we have to add up all the Peak Wattages of the equipment we plan on powering.

If you look on the back of your equipment or near the UL listing you should find watts or wattage.

  • Monitors: Sleep 25 to 40W On 100 to 140W
  • Computers: 250 to 450W On
  • Printers: 40 to 150W Printing
  • Network Switch: 0.5 to 25W
  • Network Cable Modem: 10 to 50W
  • Wireless Router: 0.5 to 10W
  • 40W Light bulb (Coil versions work best)

APC offers a UPS Selector form that might help you even more. APC UPS Selector Click Here for New Window.

Once you add up the actual wattage from each device you would like to have protected you have your Minimum Peak. Be sure to add your 40W light bulb so you can see while you are running your computer.

Let's work with a 500W system that will allow you to stay connected online and operate your computer.

UPS manufacturers always show "Best Levels" when they say 20 minutes at 850 watts. You might see the terms VA or mAH and I'll get into that but for the most part you should find watts on the side of the UPS box if not then you will need to do a little math mAH calculation.

If you only need the computer to have enough time to shut down you can match the peak watts to the UPS watts offered.

If you need to work like we do you need to increase the power levels and maybe even add battery packs to make sure you keep the power flowing.

We use APC 1200 and 1500 systems with expansion battery packs. (battery pack is the same size as the unit.)

Our 650 Dual Xeon workstations run for about 3.5 hours before we start shutting them down. The longest recorded work time was 6 hours with one monitor. But this is very power hungry equipment and your typical office or home computer will not draw as much as a server. Well, it shouldn't.

If you are like us and work rain or shine or have a service that using a slogan or motto "Inspections Rain or Shine" you should have enough power to run your office for at least 3 hours but best for 6 hours. If you walk into your office and find the power has already gone out your UPS unit (the nice ones) will have a manual startup which means you can run off your office UPS to keep the office working. Remember the low voltage lightbulb which we forget so many times.

UPS units are not very cheap when you start looking for something to actually power your system to continue work instead of offering 5 minutes to close out of your programs and shut down.

UPS units also use pure sine wave power sources which means your generator that doesn't show pure sine wave or your car inverter that shows modified sine wave will not charge the UPS batteries or work normally from these types of power sources. We have had a few people try to make the cheaper modified sine wave car power inverters run UPS devices but the UPS sees this power as a none standard power source and switches over to battery.

You can find out if your generator has clean power out by looking at the specifications. Pure Sine Wave or a picture that looks like a radio wave (rounded top and bottom.) If the specifications say Modified Sine Wave or Simulated and shows a digital wave (kind of square looking) that will not charge most UPS systems.

Equipment Recommendation:

Because we are a technical service provider and not a retail store we can make recommendations based on our experience. You don't have to take our word and you can purchase anything you would like from any place in town or online. The key is to read our recommendations and match product specifications. You might find something we want to see so post up your favorites.

Our APC 1500VA XS is no longer on the market and cost new $249.00 for the UPS and about $150.00 for the extended battery. The scales showed 300 minutes at about 200W and we found that to be a bit longer. Under full load and without overloading the thing we typically had 30 minutes like any good UPS but that's a full load so we had room lights, printers, modems, routers, two monitors, two light duty servers running and we had time to get a cup of coffee before shutting down.

Here are a few links to equipment that we use or to newer models of what we have.

  • APC Back-up Pro 1500
  • APC Pro 1500 Extra external battery (Replacement batteries are about $75.00 and these will charge off of a Solar 24vdc system or wind turbine.)

APC link to the group of Pro Back-up UPS.

Always check with the Manufacturers website for specials. From what I saw today it's cheaper to order from APC than any retail or online reseller.



When you start shopping for your new computer and it's not a laptop with a battery you might also take some sound advice and calculate the type of backup power supply you will need. Unless you never experience brownouts, blackouts or complete power grid failures for hours, days or weeks then this wouldn't apply to you. But, wait, what about spikes, surges and dirty power sources? Now it applies to everyone.