The first concern of most buyers looking for a UPS is how it will act in the presence of a power interruption. This can include anything from brownouts to blackouts. Brownouts are those times when the power level inside a home or business dips below normal levels but does not completely cut out. You may have experienced this before during times of peak power load on city power grids, such as this summer when half of the country is under heat advisory and everyone has their AC units running at full tilt.
The tricky thing about brownouts is that not all UPSs catch them. In the past I have used smaller more inexpensive (arguably cheaper made) UPSs. During multiple brownouts over the years said UPS would fail to register the power drop roughly 80% of the time.
The power would dip and everything would power off, essentially that UPS didn't catch the brownout as power wasn't immediately cut as it is with a blackout. The lights in my house would dim briefly for a few seconds and POOF my monitor would go black. Reboot the system and I was greeted with the usual "Windows was not shutdown properly…"
As we do not normally test UPS's our lab is not fully capable of reproducing every imaginable power anomaly. Due to this fact I had anticipated that I would not have the opportunity to test a brownout condition... I was wrong. On one of the hottest days earlier this summer while working on an unrelated review I noticed the office lights dim for a few moments which was then immediately followed with the chorus of beeps and tones that is the normal sound of many of my electrical devices powering up. Brownout.
The loudest beep I heard was from the Eaton 5PX notifying me that it had switched to battery power and an onscreen pop up from the monitoring software notifying me of a power loss, estimated remaining run time and a countdown to my preset system power down, in my case 10 minutes. Almost as quick as the unit had alerted me of the power loss it alerted me that power was restored and the system was back to running on AC power. When the 5PX switches over to battery power there is also a very distinct increase in fan noise as it spools up to keep the unit cool. In a normal situation this noise would be annoying, however in all fairness this noise is not a constant issue with the product and only produces itself during power loss, at which time most users would be more concerned with saving data than fan noise.
Unexpectedly I had not only tested the 5PX but also the 3S which was plugged into an entertainment center providing power to a 47" LG LCD 1080p HDTV and cable DVR. The TV had been on and running, playing an episode of a television show I had recent DVR'ed. Much the same as the PC/5PX, there had been no visible interruption. There was no flicker in the video and no momentary audio loss at all.
As luck would have it I got to "test" brownouts a few more times over the coming weeks and the results were the same. Had the lights not flickered or the UPS notified me of the power loss I never would have known, there was absolutely no disruption to the components that were attached to either the 5PX or the 3S.
With the unexpected brownout testing out of the way it was time to move on to blackout testing. A blackout is in essence full power loss and is generally of a longer duration than a brownout. Instead of waiting around for a blackout to occur, as entertaining as that sounds, I chose two methods to simulate a blackout condition. Method one was to simply unplug the UPS from the wall outlet and observe how the system behaved and record the runtime on battery power. Method two was the flip the circuit breaker controlling power to the outlet the UPS was using and again observe system behavior and record battery runtime.
The only thing more boring than cutting power to a UPS and timing how long it takes the battery to die is reading about someone watching a UPS' battery die, so I will spare you from that boredom and just sum it up quickly. Both units behaved identically. Once the plug was pulled from the wall I was greeted with a beep and an on screen message notifying me of the power loss, expected battery run time remaining and begin the shutdown procedure. As I mentioned previously I had set the delay time to 10 minutes, which in effect gave me 10 minutes before the UPSs would power down the system. At the end of the 10 minute period, open windows would start closing and Windows would start it's shutdown routine.
Once the Windows had safely shut the PC down the UPS would continue to run powering the other devices attached to it until the batteries were completely drained. The outcome was the same when I killed power to outlet via circuit breaker. An interesting side note and bit of advice, when cutting power via circuit breaker it is a good idea to notify anyone else that may happen to be in the building and therefore affected by the power loss…at least I know for next time.
In order to test the full runtime on battery power I turned off the power down option in the management software so that the UPS would just provide power to the PC until the batteries ran dead.
As I stated before, with these units we are really comparing them against themselves and the claims they make. The surprising fact here is that each unit actually – exceeded – the quoted runtime. Granted not by a long margin but still, I would rather have more runtime than less.
The other takeaway here is that in our specific power usage situation the 5PX appears to be overkill. As the power draw from our test bench PC, recorded at 225w peak by the 5PX, is so far below that of the maximum rating for the 5PX the efficiency of the unit is rather low and runtimes are not extended over that of the 3S to the degree you would expect. This does correlate with the statements of Mr. Amano.
In reality, with the power load of a single PC we are not even making the 5PX break a sweat, instead loading it down with the power load of multiple high end gaming PC's simultaneously would equate to a higher efficiency and battery run times not that far off those listed above.
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