UPS Information Please.

neiljung · 7 Feb 2008 at 13:36

Am I right in thinking that for a system with a large PSU (say 600W) this product would be no good when actually drawing anything near that?

http://www.overclockers.co.uk/showproduct.php?prodid=UP-022-AP&groupid=702&catid=55&subcat=

I thought that the VA rating was to do with the back-up time that the battery gives, but after reading around I'm still a little confused. Some people seem to be claiming to run 450W PSU systems on 500VA UPS boxes.

Is it actually the fact that I'll need to get a box with a higher VA such as this one?

http://www.overclockers.co.uk/showproduct.php?prodid=UP-015-BE&groupid=702&catid=55&subcat=

Don't want to spend the extra cash only to find out that VA just affects how long the battery runs for.

Thanks for any clarifications.

EDIT: Would the box with the lower VA rating run ok up till the power went off? I thought off-line UPS units only really passed through mains power unless the power goes out? Thanks again for any help on this.

badbob · 7 Feb 2008 at 13:51

650VA isn't much if you're going to connect a gaming rig, monitor etc. But it'll be enough for a low end system, but you only get 4 minutes of run time at 100% load. You don't want to have connected equipment that's over the VA rating of the UPS, I believe it'll trip the unit. I'm using a 1500VA APC and with two computers, phone, switcher, router and two displays I get about 25 minutes, with one 45 minutes

neiljung · 7 Feb 2008 at 14:20

Hm. I was intending to connect up a gaming rig and monitor. So if I actually started gaming and my system tries to pull more than 450W from that UPS then basically it will trip it out?

I'll need something that can throughput more watts then I guess. Seems they are more than just a big battery back-up then. Oh well.

One more UPS question; are these things much heavier on power consumption than just plugging into the mains/a surge protector? I mean if you've got a high efficiency PSU, and "green" components would running through a UPS kind of negate that power efficiency?

Amonlym · 7 Feb 2008 at 15:50

the VA rating isnt really related whatsoever to the actual battery capacity of any given unit (upto a point) the VA rating is showing you how much power the inverter can provide. the small powerstrip sized ups's are for the most part useless for anything more than a few seconds downtime.

your pc will be very unlikely to draw anything like 600w - a good start may be to get a cheap plugin power meter. im willing to bet your clsoer to 250w loaded in games for the pc and another 50 or so for a screen.

Its usually important for your psu to be a fully actve pfc unit if you plan to be using the ups anything more than once a blue moon, as these units (usually) behave much better and dont stress the ups as much.

a ups should not draw anything more than 5w for itself once the battery is charged, and you can guestimate the power it will consume charging the battery by doubling the battery capacity in watts and adding a bit (10% say) but this isnt goign to be an accurate value by any measure - but it will be a low number. a 12AH 12V battery has 140watt/hrs give or take in capacity. and most up's have lower capacity batterys. 140*2 = 280 + 10% = ~300watt hrs or 0.3kw/hr to charge

you can always add extra capacity to a ups. but there are 2 things to be aware of - unless the charge controler is able to limit the charge current to the safe limit for the charging hardware, adding more or bigger batteries could cause the charge system to eb damaged. also, be aware that small/enclosed ups's like the powerstrip one will only expect to be on for say 4 mins at full load and are thermally designed with this in mind - the max temps for various components are calculated based on this run time - so if you double the capacity (and more than double the run time - check the SLA discharge curves - the harder you push the less you get) passively cooled ups's, and tose fully enclosed WILL overheat.
this can often be fixed with the addition of a small fan in an appropriate place. if you got a high output ups it will likely be actively cooled already with a fan, and you can add batterys without fear (so long as the charger is ok!) - be sure to observe the rules and recomendations if you create a long string of parallel batterys as if they arent balanced befor you hook them up you will have a lot of current flowing about thru the conectors and this could cause trouble.

if you do add more battery capacity by using aditional cells make sure you use good quality cable (with a low AWG number, eg dont use 24awg wire from that cheapo £10 psu you got free with a case!) to connect them all, and ensure you use either high current rated conenctors to wire them up, or solder (well)

a 300w ups running at 12v is pulling 25 amps, if its 100% efficient. but most are closer to 80% efficient, AND the battery will be sagging to closer to 11.6v under that load meaning upwards of 32 amps thru the connectors and cabling.

thefishdude · 7 Feb 2008 at 16:10

think i got same unit as bad bob the apc 1500.. on my current rig i have in me sig it will run it for 50 mins at idle or dektop usage like i am doing now. and also my pc including monitor while at desktop cosumes 145watts.

the 1500 can put 865 watts max its ratted. obviously when gaming pc uses more power.

neiljung · 7 Feb 2008 at 19:31

Thanks for the info. So would this model with 800VA/540W be any good?

http://www.overclockers.co.uk/showproduct.php?prodid=UP-012-AP&groupid=702&catid=55&subcat=

My problem is that the electricity supply here seems to be prone to brownouts often several times an hour in the evenings (the light slightly dims for a half-second) so I'm pretty sure it's doing my pc no good. It also trips out now and again, about once a month, some months are fine but then it will happen several times in another.

I'd be running the UPS pretty much all the time, or that's the idea. I guess my system draws around 300W at maximum when gaming, but want to factor in for future upgrades.

Having done a little more reading it seems like an on-line UPS would be a possible solution, but these are pricier and it appears not very efficient as they're converting the input to battery power and running you off that constantly.

My psu is passive pfc unfortunately. If you could elaborate further on how this effects the ups then I'll have a better idea whether to prioritize a PSU upgrade first. I'm using the coolermaster eXtreme Power Plus 460W. Specs seemed ok from what I could tell and seemed to have ok reviews as well as being ATX 2.3 which I needed....

PSU Stats said:
1. Compliance with the newest Intel standard ATX 12V V2.3
2. More than 70% efficiency at typical load operation
3. High reliability (MTBF > 100,000 hrs)
4. Green power design to meet Energy Star and Blue Angel requirements
5. Silent operation with intelligent fan speed control
6. Multiple protection design(OVP/OCP/OPP/SCP)
7. Support dual +12V1 and +12V2 outputs for higher power usage
8. Two-year warranty

Model RS-460-PCAP-A3
Type Intel Form Factor ATX 12V V2.3
Dimension (W / H / D) Intel Form Factor ATX 12V V2.3
Input Voltage 180~264 V
Input Current 10 A @ 115Vac / 6 A @ 230Vac
Input Frequency Range 47 ~ 63 Hz
PFC Passive PFC
Power Good Signal 100 ~ 500 ms
Hold Up Time > 17 ms
Efficiency >70% Typically
MTBF >100,000 hrs
Protection OVP / OCP / OPP / SCP
Max. Output Capacity 460 Watts
Operation Temperature 0~40 Nominal Input Voltage

+ 3.3v ::: 22A
+5v ::: 25A
+12v(1) ::: 18A
+12v(2) ::: 18A
-12V ::: 0.5A
+5vSB ::: 2.5A

Max Output for 3.3v and 5v is 165 watts combined*
Max Output for 12v(1) and 12v(2) is 36A combined*
* Assuming normal operation temperature of 0-40c

20+4pin Motherboard Connector x1
4+4pin+12V CPU Connector x1
6 Pin PCI-e Connector x1
S-ATA Connector x4
4 pin Peripheral Connector x5

Also, to clarify, if I go for a higher VA UPS then it's not going to actually use more electricity in general use once charged than a lower one. Is that right? Does this apply to PSU's as well, as in a 600W unit can be as economical as a 450W depending on what power is actually drawn from it?

Sorry if that seems like a dumb question. I can see that it might.

Thanks for the help so far. Any further advice or info much appreciated.

badbob · 7 Feb 2008 at 20:11

If you want to correct for brown outs, you'll need the "smart" line which constantly monitor and correct for surges and brown outs. The back ups and other "dumb" ups's don't, just kick in during a total power failure.

800VA should be enought.

neiljung · 7 Feb 2008 at 21:18

badbob said:
If you want to correct for brown outs, you'll need the "smart" line which constantly monitor and correct for surges and brown outs. The back ups and other "dumb" ups's don't, just kick in during a total power failure.

800VA should be enought.

Are those the "line-interactive" models, or something else like a particular product range or whatever? I've seen off-line models that claim to have automatic voltage regulation and surge protection but I guess these aren't really very good?

I know the "on-line" ones are meant to be the best, but seem a bit overkill for home use as well as converting AC-DC-AC constantly so not very energy efficient as well as being pretty expensive.

Line-interactive are a decent mid-ground solution then? Man, this just get's more expensive the more I find out...heh. That always seems to be the way.

EDIT: When I was googling "smart line ups" I found this article. http://www.pcguide.com/ref/power/ext/ups/index.htm
I did GTFG earlier before posting, but didn't know what to search for and this article was a lucky find! Seriously comprehensive. Thanks to everyone who chipped in some info and helped me get off in the right direction. Hopefully this thread will be of use to the next person in need of help regarding UPS advice.