UPS with AVR recommendations

[SADShooter]

I need to acquire a UPS for a co-workers PC. She is running a medical data transfer software package which requires 24/7 run time.

I'm ideally looking for 2 hours of battery backup. We can't afford a really high-end unit, but I want some protection from a daytime surge or outage. I know APC as a brand name, and not much else. My Department tech was supposed to give me specs, but I've asked him twice with no response, so I call on the APS collective wisdom.

Thanks.

[AZRedhawk44]

When you install it, do not plug the monitor into it.  That'll save you some run time in that 2 hour window.

You're getting into expensive territory for 2 hours.  Probably outside of your cost envelope.

Assuming the PC consumes 200 watts on average through the night (a low estimate, IMO), You need a stored capacity of 3.4 amps you can draw to run it for two hours. 

(200 watts, for 1 hour, at 120vAC, is a draw of 1.66 amp-hours.  You need twice that for two hours.)

APC units are given model numbers in "VA" nomenclature.  Volt-Amps, supposedly, but they are really optimistic with their estimates. An 800VA model supposedly has 800 volt-amps.  That comes out to an ability to run 6 amps @ 120vAC.  In theory, that gives your computer (@ 200watts) your 2 hour window.

I'd suggest a SmartUPS 1500VA model of some kind.  I wouldn't trust an 800VA model to stay up for 2 hours.

One other concern:

If you lose power and this PC stays on... does your ethernet switch stay on?  How about your router?  Your ISP's gear out in the street that gets you to the innernetz?  You'll need to keep all points of communication up for this interface to run.

http://www.apc.com/tools/ups_selector/index.cfm

[SADShooter]

Thanks. That's very helpful. My 2 hour WAG isn't critical, 30 minutes to an hour is more realistic. If it goes down overnight we're hosed, I just want her to have practical recovery time if she's working with data during the day.

[DustinD]

(200 watts, for 1 hour, at 120vAC, is a draw of 1.66 amp-hours.  You need twice that for two hours.)

You're mistaken there, amp hours is a measurement of storage capacity. Amps would be the correct measurement of flow. 800VA is only telling you how much of a load it can take, it is not telling you anything about its battery, or the battery's capacity. APC does have run time charts that can help you figure it out.

I would not buy anything cheaper than the Smart UPS line if you go with APC brand procucts.

[AZRedhawk44]

You're mistaken there, amp hours is a measurement of storage capacity. Amps would be the correct measurement of flow. 800VA is only telling you how much of a load it can take, it is not telling you anything about its battery, or the battery's capacity. APC does have run time charts that can help you figure it out.

I would not buy anything cheaper than the Smart UPS line if you go with APC brand procucts.

You're correct.  My bad.

The 800VA is an estimation of the total load it can take... about 650 watts on 120vAC.  A SmartUPS 3000 can provide about 2200 watts.

There are many variations on the 800VA product line, with larger and smaller batteries for longer or shorter run-times.  You need an 800VA with a large enough battery to provide 200watts @ 120vAC for 2 hours.  The 800VA model at Staples for $159 will not do that, but the one from CDW with a slightly different model number and larger batteries for $359 will do that.

The battery size determines the potential run time, along with the active load.

A lot of APC's products tend to correlate the battery capacity to the total load, though, since the typical goal of a UPS installation is to cause a server shut-down after a monitored power outage if the power does not come on in "x" minutes.

So, you may find that most of the 1500 product line will fit your needs since they come with a battery system designed for larger loads.  An inexpensive 1500 may do what you need better than an expensive 800.

[SADShooter]

I'm not fixed on APC, they're just the primary manufacturer I'm aware of. If there's a viable alternative I'm open to it.

[AZRedhawk44]

Tripp-Lite is okay, too.

[SADShooter]

Cool. I can order Tripp-Lite through the University Store. I don't think they offer APC products.

[sanglant]

one thing to look for, if the computer dosn't have a 120/240 switch. buy a true sine wave ups or be ready to replace the powersupply. when the ups switches to battery a powersupply without the switch will try to go to 240, which causes the comp to reboot. talk about mad, you should have seen the look on my face when i figured that out.

[tyme]

one thing to look for, if the computer dosn't have a 120/240 switch. buy a true sine wave ups or be ready to replace the powersupply. when the ups switches to battery a powersupply without the switch will try to go to 240, which causes the comp to reboot. talk about mad, you should have seen the look on my face when i figured that out.

My non-sine-wave cyberpower 1500avrlcd works with two corsair power supplies just fine.  We've had a ton of brown outs and spikes recently (DFW) due to transformers dying from the after effects of the snow we got.  Neither of my corsair pwr supplies has a 120/240v switch.

[sanglant]

hmm, wonder what was wrong then. was a pcpowerandcolling PS and a APC UPS. anytime it lost power it went into the reboot cycle from hell. couldn't even get through post.
edit: ahh, "On Battery Waveform : Simulated sine wave"