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 Post subject: UPS and power consumption
PostPosted: Tue Jun 20, 2006 9:23 am 
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Joined: Tue Jun 20, 2006 9:15 am
Posts: 2
Hi All,

I have access to a couple of UPS units being "decommisioned" at work and have set aside a few to take home.

One is a server level APC 1000VA and a couple others are smaller desktop style.

My question is, recognizing the 1000VA is overkill for my gaming PC but at the same time given there is no purchase cost associated, does anyone know if the current draw of the larger UPS is significant even when the load is somewhat small?

I mean, I don't care to double my bill by plugging in a monster but if the difference is minimal based on load, I'd enjoy knowing I can stay powered up for that extra amount of time.

None of the manufacture websites specify idle current load (at least that I could find).

Thanks for reading and thanks in advance for any advice.


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 Post subject:
PostPosted: Tue Jun 20, 2006 9:45 am 
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Joined: Thu Dec 16, 2004 8:49 am
Posts: 3011
Location: Suomi Finland Perkele
First of all, Welcome to SPCR!!

An UPS by itself should not comsume almost any power, unless there is some kind of transformer constantly under load. And it should only be at laod when its charging. I should know these things, damnit... :lol:

I suggest you buy a Seasonic "something"-Angel, a Kill-A-Watt or something similar and check the power consumption yourself. Since the UPSs are basically free there´s nothing to lose :)

Btw do you know when the batteries have been changed the last time? IIRC they should be changed every few years.


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 Post subject: Thanks for the welcome and advice.
PostPosted: Tue Jun 20, 2006 9:51 am 
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Joined: Tue Jun 20, 2006 9:15 am
Posts: 2
I had thought about the Kila-watt idea and you're right, handy device to have around regardless...

As to the batteries, I also thought about that. I can't be sure when/if they were replaced but I can tell the UPS are a couple of years old.

From the little research I've done, I have found replacements for around $75 (for the APC 1000 that is). Can't speak as to the quality of these cheap replacements (maybe you could) but you can barely buy a small UPS for that much.

Will investigate further.


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 Post subject:
PostPosted: Tue Jun 20, 2006 10:27 am 
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Joined: Thu Dec 16, 2004 8:49 am
Posts: 3011
Location: Suomi Finland Perkele
I can´t really say if a battery is good or not just based on price, especially since i don´t have anything to compare to. What´s the price of original spare batteries from APC? If the cheapos are like half the price with similar specs i would probaly go for them.

And yes a kill-a-watt is a handy device to ahve around :)


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 Post subject:
PostPosted: Tue Jun 20, 2006 2:29 pm 
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Joined: Tue Jun 20, 2006 12:45 pm
Posts: 16
Location: UK
I am also interested in the power efficiency of UPS's as I wish to purchase one for my server running 24/7.

I have looked into the following line-interactive rackmount UPS's:
Liebert PowerSure Line Interactive 2 1000VA 2U
APC SUA750RMI2U 750VA 2U
MGE Evolution 800VA 1U

The only manufacturer specs I've found relating to power consumption/efficiency is for the Liebert:
http://www.liebert.com/products/english ... _23291.rtf

On page 4, section H, it lists the following:

Efficiency: >95% (Normal mode)
>90% (Buck/Boost mode)
>70% (Battery mode)

However, i have not found efficiency specs for the 240VAC 50Hz (UK) version, but I presume it would be very similar.

scapkey, if you do get a Kill-A-Watt, then I would be interested to hear your findings. :)


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 Post subject:
PostPosted: Thu Jul 06, 2006 12:49 am 
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Joined: Tue Jun 20, 2006 12:45 pm
Posts: 16
Location: UK
Ok, I've now got the Liebert PowerSure PSI 1000VA UPS and have conducted some quick tests regarding UPS power consumption at varous loads:

Code:
Load (W)  Total Power Consumption (W)  UPS Consumption (W)  Efficiency
--------- ---------------------------- -------------------- ------------
0         16                           16                   -
55        73                           18                   75.3%
126       146                          20                   86.3%
501       529                          28                   94.7%
885       905                          20                   97.8%

Ambient Temperature: 25 C


As this is SPCR afterall, the Liebert UPS is silent and is cooled passively under "normal" conditions. When running on batteries or charging, the unit is cooled by a single 80mm fan (Delta AFB0812SH) at the rear. The fan spins at a constant high speed, 4000rpm pushing 42CFM according to the fan specs and is very noisy (around 40dBA)!


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 Post subject: UPS Efficiency/power consumption
PostPosted: Fri Jan 26, 2007 9:58 am 
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Joined: Thu Oct 06, 2005 4:36 am
Posts: 4542
Location: Monterey Bay, CA
Resurrecting an old thread.....

It seems like Uninterruptable Power Supply manufacturers aren't interested in posting the efficiency vs. load curves for their products. At best, they just post one point of data.

Any other links out there for the current APS or other brands of UPS?

Anyone with a Kill-A-Watt and a UPS that cares to share their data?


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 Post subject:
PostPosted: Fri Jan 26, 2007 11:22 am 
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SPCR News Editor

Joined: Thu Feb 10, 2005 11:20 am
Posts: 2174
Location: TN, USA
I have a kill a watt and a 185W UPS and a 500W UPS but none of my Windows PCs draw more than 150W at full load. I'd have to plug in multiple PCs to try and get some varied load points.

I suppose I could do the old lamp with incandescant light bulbs trick to get some static loads of varying wattage but even then I'd have to round up light bulbs.

It's a shame load testers are such expensive, cumbersome devices...

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