Need help with choosing an UPS!!

[Philib]

Hi guys, I spoke to one of my friends (an electrical engineer) on the phone earlier and after a short conversation he advised me to get a UPS for my computer. I have been getting extremely bad computer issues recently and would like to rule out a bad power supply as the cause. Also I think if this isnt the reason for my issues its going to be a brill investment anyway.

So anyway. I head on to amazon and type in UPS's in the search bar and am greeted with a mine field of choice all with different amps, volts and watts. Would you guys be able to help me choose what one is best for me. I am definitely not an electrical engineer and this is all quiet daunting for a simple locksmith.

At the moment I use a 10 sockets extensions cable but only use about 4 for my computer, but, if I was to get an UPS I think I would have a lot more plugs into it as I could run my home cinema system of it as well.

Many thanks guys.

 

[nex-s]

Philib, sorry for getting into your thread like this, but I also have a question for the guys which no-one has answered yet and it may be of interest to you as well.

See if my PC draws say ~450W what UPS I need if I don't care about the run-time in case of power outage? Is a 400W UPS able to only output those 400W and nothing above that or is that more like the capacity of the battery?

I too want to get clean power to my PC, but totally don't care if it shuts down as soon as the power goes out in the house or whatever. I assume this may be the same case for you Philib. I don't want to spend tons of money to run my system 5 mins after power cut, but would rather prefer something that just delivers the clean power. By this I mean a decent brand, but say not the most powerful of UPS's in a specific line, but rather one that's just enough.

 

[jimbo32]

I did a little research on this recently, and found a good guide here.

Tl;dr answer is that you want to measure the power draw in watts of your system under load. Once you have that figure, multiply by 1.6 to get the VA requirements and add 20-25% for wiggle room.

So a system that draws 700w from the wall under load would need:
700 x 1.6 + 20% = A UPS rated at 1344 VA

(According to the dude who wrote the guide, the VA rating of a UPS is usually more reliable than it's wattage rating)

You also want to avoid UPS's which use simulated sine-wave output. Apparently, they don't play nice with active PFC psu's (ie: all decent modern psu's).

EDIT:
@nex-s
I was thinking along the same lines, and I found something that offers just surge protection and voltage regulation while being considerably cheaper than a full-on UPS. The Opti-Ups SS2000 is rated at 2000VA (~1000w). I'm not sure what the company's rep for reliability is, but this unit has some nice customer reviews on some of the major North American e-retailer sites (NCIX, Newegg). NCIX has it for $40, which is obviously a lot cheaper than a UPS with a similar VA/w rating.

 

[Philib]

Tl;dr answer is that you want to measure the power draw in watts of your system under load.

Is this what your system draws or the maximum your psu can do? For example my PSU is rated at 750 but obviously my system doesnt draw anywhere near that.

Also I think I may be in the same boat as nex-s. I dont really need a battery backup I just need my electricity supply cleaned up. Now after speaking to the guys at APC he managed to (almost) convince me I needed a "APC Power-Saving Back-UPS Pro 900, 230V" and after listening to his advice I have to admit the features sounded tasty even if it is £160. But if you say you can get a semi-ups with a voltage regulator and serge protector for around the £30 mark then I have to admit its hard to justify the price for the full on ups-pro.

 

[tinytomlogan]

VA rating x 0.6 = wattage rating. Id always aim for a little above what you need though.

Cyberpower make good units, I have 3..........

 

[jimbo32]

Yeah, it's just the max draw under load. Although I think you may end up starving your psu should you upgrade your PC later on and increase the VA/wattage beyond what the UPS/AVR is capable of handling. I've no idea what the consequences of that would be, though I imagine it probably wouldn't be good.

If you're not worried about losing progress on open documents (or whatever) in the event of a power failure, it seems to me that the £30 option would be perfectly fine. However, I don't know the ins and outs of how these things work, so maybe there's an electrical engineer kicking around OC3D who could chime in with some advice?

From reading through some of the customer reviews, I can tell you that there were a few people who mentioned having problems with voltage fluctuations (or somesuch). The problems could've been caused by "dirty" power from the utility or crappy wiring in the house, but the issues were apparently cured by the Opti-UPS unit. Those are obviously anecdotal reviews rather than scientific testing results, so I suppose they should be taken with a grain of salt. But it certainly seems worth taking a shot and saving £100 or so.

EDIT:
As Tom implied (I think), rather than measuring load wattage, you could just take your psu wattage and multiply by 1.6 to get your VA requirements. Then add ~20% just to be safe. Although if you'll be adding your home theatre gear (or PC peripherals) as well, you'll need to add the manufacturers wattage rating for each device to the rating of your psu before doing the calculation.

 

[tinytomlogan]

Id go with load + a bit fella. the Cyberpower ones go high enough for most rigs considering my 4way Crossfire rig on maxichat only pulled 1250w most normal rigs will be perfectly fine

 

[jimbo32]

Id go with load + a bit fella. the Cyberpower ones go high enough for most rigs considering my 4way Crossfire rig on maxichat only pulled 1250w most normal rigs will be perfectly fine

Good lord. I guess that's a good indication of how much overkill people usually have with their psu's. It's not uncommon to see builds with 1000w+ psu's with a single gpu and air cooling.

But yeah, if Tom recommends Cyberpower, I imagine you should be safe with one. A quick look shows a 1350VA Cyberpower going for around $115 (£73 before taxes). That's still a decent savings over the quote you were given for the APC model.

 

[Philib]

What one are you referring to? I cant find anything near that price.

This one is a bit cheaper then the APC version but its still not as cheap as that.

 

[jimbo32]

That's the one. A few places here have it on sale for ~$115. Considering the large price difference, it might be worth your while to import it from Canada and pay the fees.

Here and here

NCIX carries it as well, though it isn't on sale. They do have price-matching though, in case those others don't ship internationally.

 

[Philib]

Tbh I think I will just buy it from the UK although the difference is vast, if it does break, its got to go a long way back lol.