Understanding UPSs and recommendations

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berrys

225 posts

Master Geek

# 78795 8-Mar-2011 11:48

Hi,

Looking at getting a UPS or 2 for my office. Essentially I want my workstation PC, a couple of NAS devices and WHS to be connected.

What I am unsure of is how long the batteries last for when the power goes off - my workstation has a 1200watt power supply I think (does this matter...?) Ideally the longer the better obviously.

I've heard that batteries need to be replaced every 2 years - is this true?

Any advice much appreciated

Shane

Ragnor

8035 posts

Uber Geek

Trusted

# 446614 8-Mar-2011 12:24

Best way to size the UPS is to grab one of those cheap Elto power meters (<$25 from bunning, mitre 10 or the supermarket). Measure the power used by each device you are going to connect to the UPS to get a rough watts total then convert to VA (see below).

Remember to put the device under load to get a more representative value, ie: don't measure your PC while it's idle crank some programs/games/benchmarks.

UPS's are typically quoted in VA (volt amps), as a general rule of thumb: watts used / 0.6 gives you an safe approximate VA value to aim for.

A good 2000VA UPS is going to cost you quite a bit, probably around $1k+

So definitely measure with a power meter.

I suspect even though your PSU is 1200w it won't be using near that amount.

APC have a UPS calculator online too:
http://www.apc.com/tools/ups_selector/index.cfm

gzt

10982 posts

Uber Geek

# 446658 8-Mar-2011 14:31

I will mention soft factors. It is worth giving thought about other things which happen when power is not available.

Light can be a problem, especially if maintenance or hardware reconfiguration is required in those conditions, or just to see where all the plugs are going.

Also, consider creating power profiles to enable in the event, speedstep/powernow to minimum use, disabling scheduled scans/tasks etc.

Some apps/services do not behave well with speedstep/pn enabled, some verification ahead of time is a good idea to ensure efficiency.

A second smaller efficient monitor may be worth considering if available.

Also, when it happens, you can find yourself shutting down some systems and peripheral devices to keep the rest running longer, even moving data between systems.

Having a clear idea of the required configuration, and what the fallback positions are, saves a lot of time in the event.

jjnz1

1135 posts

Uber Geek

Subscriber

# 446667 8-Mar-2011 14:50

Instead of one big UPS, look at getting a few smaller ones. Might cost you the same at the start, but replacing the batteries will end up cheaper.
And yes, changing a battery every two years is about what you would expect, but the UPS device should perform monthly automated self-tests and notify you when its time to replace the battery.

Also, using maybe 1 small UPS per PC might be an idea as each PC can then administer its own power supply and shut down accordingly.

Another downside to using 1 big UPS; some UPS's cannot be managed by more than one PC, so if the power goes, the other PC's will not shut down when needed (without serious scripting from a programmer anyway).

APC are a good brand in terms reliability and performance. I recommend them. In my office I have 3 of the 500VA APC models.

berrys

225 posts

Master Geek

# 446669 8-Mar-2011 15:07

This is great info guys - Big thanks!

Niel

3267 posts

Uber Geek

Trusted

# 446841 9-Mar-2011 06:14

Typical desktop with low cost UPS (like from DSE etc.) you are looking at a run time of about 15 minutes if you quit your heavy load game when the power goes out.

The night I installed a UPS for my in-laws the power went out. It was great having the monitor light up the room and took us a while to understand why the PC is running but everything else is off ;-).

You can never have enough Volvos!

Regs

Cloud Guru
4060 posts

Uber Geek

Trusted

Snowflake

Subscriber

# 447038 9-Mar-2011 18:03

i always buy APC ups's. They inetgrate nicely into windows and show up as a battery. You can then use the windows power settings to control sleep, shutdown settings etc.

i havent found another brand that integrates as well - usually you have to deploy crappy 3rd party software

you can usually egt replacement batteries for APC too.

therefore, i only recommend APC :-)

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Snowflake
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