UPS and power consumption

PSUs: The source of DC power for all components in the PC & often a big noise source.

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scapkey
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Joined: Tue Jun 20, 2006 9:15 am

UPS and power consumption

Post by scapkey » Tue Jun 20, 2006 9:23 am

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.

nici
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Joined: Thu Dec 16, 2004 8:49 am
Location: Suomi Finland Perkele

Post by nici » Tue Jun 20, 2006 9:45 am

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.

scapkey
Posts: 2
Joined: Tue Jun 20, 2006 9:15 am

Thanks for the welcome and advice.

Post by scapkey » Tue Jun 20, 2006 9:51 am

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.

nici
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Joined: Thu Dec 16, 2004 8:49 am
Location: Suomi Finland Perkele

Post by nici » Tue Jun 20, 2006 10:27 am

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 :)

el-tel
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Joined: Tue Jun 20, 2006 12:45 pm
Location: UK

Post by el-tel » Tue Jun 20, 2006 2:29 pm

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. :)

el-tel
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Location: UK

Post by el-tel » Thu Jul 06, 2006 12:49 am

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: Select all

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)!

CA_Steve
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Location: St. Louis, MO

UPS Efficiency/power consumption

Post by CA_Steve » Fri Jan 26, 2007 9:58 am

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?

dhanson865
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Location: TN, USA

Post by dhanson865 » Fri Jan 26, 2007 11:22 am

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...

BrianF
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Re: UPS and power consumption

Post by BrianF » Mon Jan 05, 2015 9:34 am

Resurrecting again....

I recently posed this question and found, as el-tel did many years ago, that UPS have a not-insignificant overhead. Even a brand new "EnergyStar" rated unit I just looked at draws 20 watts....with NOTHING connected to it...all day everyday, with additional loss according to load.

While 20 additional watts may be insignificant for a server running 24/7, for home PC use, this represents a tremendous waste since for at least 2/3 of the day the PC is turned off and the UPS is essentially unneeded. I realize that the battery needs to be kept "topped up", but there has to be a better topology.

In this day and age of energy consciousness I would have thought someone would have come up with a more "adaptive" design where when the battery is at 100% the trickle charge gets cut for a certain amount of time, then cycles back on etc, with perhaps an even longer off interval when the load is nil.

CA_Steve
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Re: UPS and power consumption

Post by CA_Steve » Mon Jan 05, 2015 11:15 am

Hello frequent necro-poster.

Not sure where you are getting this 20W stuff from. I have a couple APC BE750's. They draw 5W from the wall at idle/no load. While I'd like to see it down in the few watts range, this is a small price to pay for the frequent power events I have in my area.

xan_user
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Re: UPS and power consumption

Post by xan_user » Tue Jan 06, 2015 1:05 pm

my ups are about 5-10w with no load.

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