Questions about UPS units
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You're using a netleaflet as a server?
Software Zen:
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The power supply is a Corsair 750W (it's a bit too powerful for my config it seems, but there were no "smaller" models, so...) At any rate, I'm reading some stuff on the interwebs and it seems that power supplies with active PFC usually don't work with UPS units that generate a pseudo-sinusoidal output wave. :doh:
If you truly believe you need to pick a mobile phone that "says something" about your personality, don't bother. You don't have a personality. A mental illness, maybe - but not a personality. - Charlie Brooker My Photos/CP Flickr Group - ScrewTurn Wiki
Yes and no. The problem as I understand it, is that at startup, or following a brief interruption (eg the time your ups takes to switch to battery) causes the PSU to briefly draw its maximum power to recover and that if you've got an UPS with more output power than your PC can draw you'll be fine. Remember that your PSU is rated in terms of output power, not input power (which will be higher due to conversion losses). It's probably on the box or pamphlet somewhere but your PSU should be at least 80% efficient.
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My main concern is about compatibility with active power factor correction (PFC) PSUs. And, I'd also like to avoid UPS units with cooling fans.
If you truly believe you need to pick a mobile phone that "says something" about your personality, don't bother. You don't have a personality. A mental illness, maybe - but not a personality. - Charlie Brooker My Photos/CP Flickr Group - ScrewTurn Wiki
I've got a big 1300VA model from APC. The fan either runs silently or not at all except when its on battery power. There's not much you can do about it, once you run enough power through something passive cooling just can't keep up unless you make the device huge.
The European Way of War: Blow your own continent up. The American Way of War: Go over and help them.
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The problem with PFC PSUs is that they don't like non-sinusoidal waves and they usually shut off. Moreover, they interact with the inverter of the UPS causing heavy distortion of the generated wave, thus reducing the effective capacity of the latter down to 30%. I'd be interesting in knowing what PSUs yo have. On a side note, I also suspect that things work differently with 110V or 220V ratings (I'm in Europe, so my equipment runs at 220V/50Hz).
If you truly believe you need to pick a mobile phone that "says something" about your personality, don't bother. You don't have a personality. A mental illness, maybe - but not a personality. - Charlie Brooker My Photos/CP Flickr Group - ScrewTurn Wiki
Dario Solera wrote:
On a side note, I also suspect that things work differently with 110V or 220V ratings (I'm in Europe, so my equipment runs at 220V/50Hz).
afaik the only difference is that your PSUs run one or two percent more efficiently and can get marginally more DC out before overloading.
The European Way of War: Blow your own continent up. The American Way of War: Go over and help them.
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I recently purchased a cheapo UPS, 400W/700VA. It turned out to be undersized for my PC*, as it simply shuts off when unplugging the power cable. Also, when the PC is at full load, the UPS unit goes overloaded and the beeper starts shouting. How do I know how much power my PC uses without using a watt-meter (which I don't have)? I calculated that it should be within 400W, but I'm lost at this point. When the UPS is overloaded, the software says it's using 154% of its power rating, which would be more than 600W... *) Intel Core i7 920, nVidia GTX275, 2x WD Velociraptor, 12GB 1,333 MHz DDR3
If you truly believe you need to pick a mobile phone that "says something" about your personality, don't bother. You don't have a personality. A mental illness, maybe - but not a personality. - Charlie Brooker My Photos/CP Flickr Group - ScrewTurn Wiki
Dario Solera wrote:
cheapo UPS, 400W/700VA
Do NOT buy any unit less than 800VA or less than 22lb or 10 KG in weight. These are crap and generally not suitable for a computer. The battery is probably already worn out. The weight restriction ensures that there are 2 batteries in the unit instead of 1. I recommend powercomm 800 to 1500VA units that sell for around $100 USA. Or shopping on ebay for a used APC model. I have a dozen or so powercomm king pro units with (dual 8AH 12V batteries) at work and they last about 30 minutes for a dual core development machine. At home I have a 1250VA powercomm I bought 8 to 10 years ago. It powers my core2 quad q9550 with 5 hard disks for 1 hour. I have replaced the batteies on this 2 or 3 times with batteies bought onlone. These are generally $17 to $20 each shipped and are the same batteries that many APC models use. I recently upgraded this and got an APC smart UPS 1400 used from ebay for $185 shipped. With its 2 12V 18AH batteries and (30KG+ weight) I can get over 2 hours of power out of that.
John
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Yes and no. The problem as I understand it, is that at startup, or following a brief interruption (eg the time your ups takes to switch to battery) causes the PSU to briefly draw its maximum power to recover and that if you've got an UPS with more output power than your PC can draw you'll be fine. Remember that your PSU is rated in terms of output power, not input power (which will be higher due to conversion losses). It's probably on the box or pamphlet somewhere but your PSU should be at least 80% efficient.
The European Way of War: Blow your own continent up. The American Way of War: Go over and help them.
dan neely wrote:
Remember that your PSU is rated in terms of output power, not input power (which will be higher due to conversion losses). It's probably on the box or pamphlet somewhere but your PSU should be at least 80% efficient.
Now, I have to admit that I completely forgot about that aspect. The efficiency should be 87%.
If you truly believe you need to pick a mobile phone that "says something" about your personality, don't bother. You don't have a personality. A mental illness, maybe - but not a personality. - Charlie Brooker My Photos/CP Flickr Group - ScrewTurn Wiki
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I recently purchased a cheapo UPS, 400W/700VA. It turned out to be undersized for my PC*, as it simply shuts off when unplugging the power cable. Also, when the PC is at full load, the UPS unit goes overloaded and the beeper starts shouting. How do I know how much power my PC uses without using a watt-meter (which I don't have)? I calculated that it should be within 400W, but I'm lost at this point. When the UPS is overloaded, the software says it's using 154% of its power rating, which would be more than 600W... *) Intel Core i7 920, nVidia GTX275, 2x WD Velociraptor, 12GB 1,333 MHz DDR3
If you truly believe you need to pick a mobile phone that "says something" about your personality, don't bother. You don't have a personality. A mental illness, maybe - but not a personality. - Charlie Brooker My Photos/CP Flickr Group - ScrewTurn Wiki
I've used several from here Eaton UPS[^], including data centre, rack & personal models - they cost a bit more, but they're ultra reliable and support's good too. My rule of thumb for personal stuff is to get a UPS that exceeds requirements by at least 50% - ie if you're drawing 500W then get a 750W UPS at minimum
Multi famam, conscientiam pauci verentur.(Pliny)
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The thing runs off 12V. Get an old car battery, hook a battery trickle charger up to it, and run the thing off that. It will probably run for several days off that. Heck - go green, buy a 40W solar panel and hook that to the battery, and go off grid! :wtf: :^)
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The power supply is a Corsair 750W (it's a bit too powerful for my config it seems, but there were no "smaller" models, so...) At any rate, I'm reading some stuff on the interwebs and it seems that power supplies with active PFC usually don't work with UPS units that generate a pseudo-sinusoidal output wave. :doh:
If you truly believe you need to pick a mobile phone that "says something" about your personality, don't bother. You don't have a personality. A mental illness, maybe - but not a personality. - Charlie Brooker My Photos/CP Flickr Group - ScrewTurn Wiki
So assuming your 750W supply is heavily loaded divide by 0.65 to get the rating on the UPS (to correct for the way they are overrated). Also, never plug a laser printer into a normal UPS, they can't handle the fusion heater load unless they are specifically rated for a laser printer (VERY few are). As a general rule, get everything running and pull the UPS plug from the wall, if nothing reboots or dies you may be ok, if anything fails or reboots you just have a surge suppressor. Most (aka cheapP UPSs that people buy are offline and switch online when needed. The problem with this that they also have slow switchover times, often 8ms or longer so many glitches in your power will result in the UPS doing nothing. If you really want, APC has some nice white papers on sizing and the types of UPSs (online and standby). Jay