PDA

View Full Version : UPS's



Thebananamonkey
17-06-2008, 10:20 AM
Having just spent a small fortune on my comp, I thought I'd be wise to put some sort of protection in line before it. But I've got one niggling question.

The PSU I'm looking at has a maximum rated output of 500W... If my comp has a 620W PSU, does that mean I'm starving it of 120W? And then whatever else I decide to plug into it.

A 500W looks like my only option, as PSU's jump from ~$180 to about ~$1000 after this point. Any advice?

wratterus
17-06-2008, 01:39 PM
Ae?

Sorry, I'm confused.


Did you mean UPS those 2nd two times?

password
17-06-2008, 01:43 PM
the ups is 500 and the psu is 620watt.... dont worry, i get muddled myself

Graham L
17-06-2008, 01:54 PM
The computer is unlikely to be using the full nameplate power. At the most you might plug some network equipment into the UPS as well as the computer. You do not plug a laser printer (or a heater) into a "domestic" UPS.

Apart from a bit of extra surge protection, the purpose of the UPS is to give you time ( a few minutes) to do an orderly shutdown of the computer if the power goes off. The more power you pull, the fewer minutes you get. Life's like that. A 500W (or VA) UPS is likely to have a 7AH gel battery. At 500 W, it will draw about 40A from the battery. You don't get 7/40 ths of an hour; you would get a very few minutes.

password
17-06-2008, 01:55 PM
What about something like this for a lil bit more?

http://www.madkiwi.com/product_info.php?products_id=49

Thebananamonkey
17-06-2008, 02:58 PM
Basically, my comps PSU is 620W. I'm not sure how much of that it's drawing at the moment. But if I buy a UPS rated at 500W, then I'm effectively losing 120W immediately.

I don't want to do that. Plus screens, stereo equipment, it's going to get unpowerful fairly quickly. That's assuming I'm looking at this the right way.

So will my comp be able to draw any more than 500W when the UPS is just humming away normally?

Regarding the madkiwi one. Do va's translate into wattage? Or do I have to find that another way?

Or should I just get a good surge protector and save myself the hassle?

wainuitech
17-06-2008, 03:16 PM
Remember One thing - when a UPS is running normally, its actually running off the mains power, The battery only kicks in when there is a power problem, So if you have a brownout (power Drop) the battery kicks in for a few seconds, or as long as the brown out is occurring.

In a power cut, apart from the obvious, that the lights have gone out :) the battery is not meant to keep the PC / Equipment going indefinitely, only long enough to save any work, and shut the PC down in a safe manner instead of a sudden crash, a standard PC on a Liebert Powersure Assistant 650 UPS, which is the ones I use lasts around 30-45 minutes easily with the PC doing nothing (if you can put up with the no power alarm beeping) Obviously you cant carry on as if nothing has happened.

While a surge protector will stop a power surge, in a power drop / outage it wont do any thing at all, the PC will suddenly crash due to no power.

gary67
17-06-2008, 06:31 PM
Would one of those be able to run more than one comp I'm looking to get something and need to power 2 comps at least

wainuitech
17-06-2008, 06:42 PM
Would one of those be able to run more than one comp I'm looking to get something and need to power 2 comps at least Not the one I mentioned above :groan: Have tried myself in the workshop on 2 PC's, Thought I may be able to save a few $$ But the load is to much for it - 2 PC's & 1 17" CRT.

A larger one may work OK, but for the price I just brought a 2nd one.

tweak'e
17-06-2008, 08:58 PM
a couple of things.....

a pc often uses max power on startup. CRT's also use large amounts to startup.
you really need a UPS that far more than what the power supply is. ie if PSU is 620w then 700w UPS is minimum. i would go more due to adding an LCD monitor. for CRT you will need a LOT more.
my old pc had 1000w ups mainly because the CRT monitor wouldn't fire up on smaller ones.
no point having a ups and when there is a power cut you have no screen so you can't save anything and shut the pc down.

the other thing... basic UPS don't do much when there isn't a power cut. however interactive ones fully regulate the power, they run all the time. the only thing that changes in a power cut is where the power comes from. downside is if you run one thats a bit small you will over work it and it won't last long.

paulw
18-06-2008, 08:30 AM
Remember One thing - when a UPS is running normally, its actually running off the mains power, The battery only kicks in when there is a power problem, So if you have a brownout (power Drop) the battery kicks in for a few seconds, or as long as the brown out is occurring.



As he said. Also there is another type of UPS but will cost more a AC > DC > AC version. This way the power is being filtered before your PC and spikes , sages and surges should not be as much of a problem..

Thebananamonkey
18-06-2008, 08:49 AM
Sages have never been an issue for me. :p

So if there's no brownout/power cut, is it possible for my comp to still get the full 620W while connected to the UPS? And it only goes down to 500W when there's actually a problem?

If that's the case, then I don't think I actually have a problem.

Agent_24
18-06-2008, 04:57 PM
Remember One thing - when a UPS is running normally, its actually running off the mains power, The battery only kicks in when there is a power problem, So if you have a brownout (power Drop) the battery kicks in for a few seconds, or as long as the brown out is occurring.

In a power cut, apart from the obvious, that the lights have gone out :) the battery is not meant to keep the PC / Equipment going indefinitely, only long enough to save any work, and shut the PC down in a safe manner instead of a sudden crash, a standard PC on a Liebert Powersure Assistant 650 UPS, which is the ones I use lasts around 30-45 minutes easily with the PC doing nothing (if you can put up with the no power alarm beeping) Obviously you cant carry on as if nothing has happened.

While a surge protector will stop a power surge, in a power drop / outage it wont do any thing at all, the PC will suddenly crash due to no power.

Not if you're running an on-line or 'true' UPS: you'll be running off the battery all the time... But most UPS designed for home use are either offline or line-interactive

williamF
18-06-2008, 05:15 PM
the 620W rating is the OUTPUT power of the 3.3,5 and 12 volts combined, the input power is usually and generally alot less so any reasonable UPS should operate the supply

tweak'e
18-06-2008, 07:45 PM
Sages have never been an issue for me. :p

So if there's no brownout/power cut, is it possible for my comp to still get the full 620W while connected to the UPS? And it only goes down to 500W when there's actually a problem?

If that's the case, then I don't think I actually have a problem.
with the BASIC ups thats basicly right, but if your monitor is off when there is a power cut you may not be able to get to turn on. also pc may have problems if you do something very intensive.

pc will certainly run at less wattage most of the time, but not all the time.