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DC Forum: Need some advice on Uninterruptible Power Supplies

Smoke

Smoke

Distributed Computing Elite Member
Here?s the problem.

I?ve got the Crazee Crack Rack running 13 computers ? all 1800+ XPs.

I keep getting these momentary power outages that last only a couple of seconds. Only 4 of the 13 computers have settings in their BIOS to ?Run after Power Failure? (or words to that effect). The rest just sit there until I discover that they are not running and then I have to manually start them up. These are all caseless computers and I have to switch the KB and Mouse and monitor as I start each one up. It takes quite a while to get all of them up and running.

Now I know the answer is to get enough UPSs to handle these momentary power outages. But what I need help on is what would be the most economical way to go? BTW, these computers are not on the generator circuit so any extended power outage will still have me re-starting them manually. But that?s not the problem that I?m trying to fix ? just avoiding the momentary outages would be good enough.

There were approximately six-hours of wasted time today resulting in the loss of around 27 Seti WUs. 🙁

Crazee Crack Rack

Work Bench with troublesome "Crazee06" and "Smoke08 - The TeAm's SetiQueue"
 
I've had good luck with APC UPSes, but they can be expensive. Belkin makes good UPSes, and by some accounts (fortunately I've not had to worry about this personally), they honor their warranty / insurance more willfully than APC does. IIRC, Belkin should be a little cheaper. I'd stay away from the lesser-well-known cheapo brands, FWIW. BTW, I'm sure that some who frequent ATHD can get you a link to a low-cost APC or Belkin unit that has tons of rebates at Staples or somewhere. 🙂
 
The question is, how much wattage are you using in a steady-state condition?

If you guess and say 100 watts per unit, that is 1300 watts that the UPS would need to be able to carry for a few minutes.

A UPS will also have a maximum current value that it can carry, but that is mostly for starting things, not steady state. It also comes into play if you try to plug too many things into an underpowered UPS.

If you say 150 watts, then that is almost 2000 watts capacity you need, even though you only need it for less than a minute.

I'd guess that a 2000 watt UPS would handle it pretty easily. If you had a clamp on ammeter, that could take out the guess work. Multiply the current by 110 or 115 and you get wattage. I've got one, but it's very old and I have no clue if it works.

What is your budget? (I was tempted to say "watt is your budget" but I restrained myself. 😉
 
Links to some good deals would be really appreciated. I would like to know how many of these computers could a UPS of ???? size handle?

There would be at least 14 computers all demanding voltage at the same time. I don't know how to figure what wattage each would need. I don't think each would need the full rating of their power supplies ... would they?

Edit: I see Jon answered part of the above at about the same time as I posted. 😛

Guess I'll get my son to come over and do that (the ammeter test) for me ... he is an electrician. 😀
 
Originally posted by: JonB
The question is, how much wattage are you using in a steady-state condition?

If you guess and say 100 watts per unit, that is 1300 watts that the UPS would need to be able to carry for a few minutes.

A UPS will also have a maximum current value that it can carry, but that is mostly for starting things, not steady state. It also comes into play if you try to plug too many things into an underpowered UPS.

If you say 150 watts, then that is almost 2000 watts capacity you need, even though you only need it for less than a minute.

I'd guess that a 2000 watt UPS would handle it pretty easily. If you had a clamp on ammeter, that could take out the guess work. Multiply the current by 110 or 115 and you get wattage. I've got one, but it's very old and I have no clue if it works.

What is your budget? (I was tempted to say "watt is your budget" but I restrained myself. 😉
Click to expand...
A 2000 watt UPS is going to be expen$iv?. This UPS provides 980 watts, and costs over US$500. I'd recommend smaller capacity UPSes in larger quantities. 🙂
 
To provide adequate power to those machines (13 of them) you'll need a pretty massive UPS. That's the equivalent of a full rack of servers. It's important to remember that UPS are measured in kva which is not watts. Assuming a load of 2000 watts, in order to have 10 minutes of run time you'd need a APC Smart-UPS 5000VA (MSRP 3,075) or a Symmetra (well over 8,000 dollars).

It's going to be costly to do it. Alternatively, you can get a Back-UPS ES 500 per blade at 59.99 each (MSRP), but then again, multiply that by 13 and you're talking a large investment.

A standard sized UPS just won't cut if for you if you want to protect all 13 blades.
 
Engineer,

That link returns a page informing me that "my cookies are not enabled"? But they are ??? so give me the search parameters you used and I'll try it that way.
 
The link works now? Wonder why it didn't work the first time?

I think I need a cheaper solution. / cheap cheap cheap / 😛 😉

Do you think three of those would do it?
 
Originally posted by: Smokeball
The link works now? Wonder why it didn't work the first time?

I think I need a cheaper solution. / cheap cheap cheap / 😛 😉

Do you think three of those would do it?
Click to expand...


Two might do it...not sure. This model was on sale at CompUSA for $149.xx + tax a few weeks ago.....Sales come and go....if you wait a week or two, you might find a great deal on individual UPS'
 
You are not likely to find a single UPS that:

1) will support the entire load

and

2) is not expensive

and

3) does not require at least a 20 A outlet

and

4) is not very, very heavy
 
Yeah, there probably isn't a really cost-effective answer. 🙁

It's not so bad when I'm around but if I go on a trip it really causes problems.

If only all of the computers had the option in their BIOS to RUN AFTER POWER FAILURE, there wouldn't really be a problem. Is there a possible solution going down that road?

The motherboards in question are:

PcChips M841LR
Elite Group K7S5A (I think this one has the option in the BIOS)
Elite Group K7VMM+ Rev. 3.1
Elite Group L7SOM
BioStar M7VIG

I need to double-check each of the above and see which ones need a "special" bios. And then to find that "special" bios.
rolleye.gif
 
Greg,

You could wait until Sunday and order a few APC 725VA units from OfficeMax.com. They are going to be $79.xx on sale (Starting 9/21/03) and you could use one of the coupons from here...If they aren't on the website or not at that price on the website, then all bets are off.
.


3 of them would be around $207.xx + tax after the $30.00 off $150 coupon and Free SHIPPING! 🙂

Not bad for 3 725VA supplies! 🙂
 
Originally posted by: Engineer
Originally posted by: Smokeball
The link works now? Wonder why it didn't work the first time?

I think I need a cheaper solution. / cheap cheap cheap / 😛 😉

Do you think three of those would do it?
Click to expand...


Two might do it...not sure. This model was on sale at CompUSA for $149.xx + tax a few weeks ago.....Sales come and go....if you wait a week or two, you might find a great deal on individual UPS'
Click to expand...

JW saw my UPS. It is somewhat similar to the 1500 APC you posted Engineer but it is only 1,100 Watts (but has long back up time with 80 Amps of battery on board). It runs 7 PC's with no problem so I am confident you could just use 2 of those 1,500 Watters for your 14 machines. Just have to put the UPS units on two different circuit breakers.



 
You only need the UPS for those mobo's that don't restart, so that helps some.

Also, as far as wattage goes, I have to follow up on B52GUNR's comment about KVA versus wattage.

If your load is purely resistive (and computer power supplies are not) then KVA would be exactly equal to KW.

Since computer power supplies use transformers, they have a reactive phase shift with makes their KVA demand higher than their Wattage, but not by much, and for short term loading, can be mostly ignored. The power factor of a modern high frequency switching power supply is probably 0.85 or 0.90 lag. The older ones (non-switching) are nearer to 0.60 lag and would have a drastically different KVA load profile. The affect of the lag on wattage is not linear, such that 0.95 is much better than 0.90 which is much much better than 0.60. (if you must know, it is sinusoidal instead of linear)

What does that mean in real terms for Smokeball? It means, put the newest switching power supplies on the motherboards that need UPS's. Put any older ones on the motherboards that auto restart.

Anybody in information overload yet?
 
ha ha

I'm sure glad for that last line for I was getting a little "glazy". lol
 
Thanks for the links, Engineer. I have an OfficeMax nearby so I'll have to think about those 725W models.

I'm just torn between spending $200+ on UPSs or building some more crunchers with that same money. Priorities Priorities. lol
 
This is what we used for a full rack of servers and routers. You can add external batteries to increase the run time. As others have mentioned you need to look more at VA to determine your actual run time. It would be best if you could clamp meter a single wire at the breaker and see what the actual draw is. BTW you can run that model on a 15A breaker but it is a considerable investment until you compare it to the cost of renewing all the batteries in a bunch of smaller ups units.

<edit> should have read down the thread more I was thinking a small UPS on each blade not the three larger units Engineer is talking about.
 
I have an old UPS I will give ya if you pay for shipping. It was what I was running all my servers and stuff on when I was doing web hosting. It is a Tripplite BC750A that weighs about 30 lbs without battery, and is 18" deep, 8" tall, 7" wide. (or about 1/2 the size of my computer case.) It is suppsidly only 750 watts, but that is bull. I was pulling over 1500 from it. (but it would only hold 1500 for about 20 minutes) The battery has since died. You would have to modify the wires to hook up a car battery, or you could by a replacement for the unit, but it was $200. A car battery will more than cover it, but I reccomemnd a dry cell such as an Ultima so no outgassing will occur.

It is rated at 750 watts for 1 hour with the standard 60AH battery.

I can not guarrantee it works because it has been in my attic for about a year. If something is wrong with it any competent electricion should be able to fix it for cheap. It was working when I put it away. I have a copy of the manual around somewhere as well.

 
Ahhh... This is what I am looking into buying ...

What size P/S are you using your system? What kind of Motherboards/CPU? Hard Drives? CD ROM? Floppy?

Best Bang for the dollar UPS? I think Belkin Is.... I got the 800VA... I can run 5 Computers on it and still get around 10 mins of up time. 🙂

I am going to get a 1200VA as I too am looking at buying another one. You can get one shipped for about 120 bucks.

Belkin Review 800VA

The 800 looks just like the 1200... This Belkin UPS is rated at 1200VA (670W) for up to 100 minutes of backup time. It has 6 outlets (4 battery backup and 2 surge protected). Features serial and USB ports, and a 3 year product warranty. 670Watts for 100 minutes... That is awsome for 100 bucks!!! 🙂

If you don't know or really want to know more then you really need to know about UPS's...



Go Here.... Excellent read!!!

 
ICXRa, that is a little more than I wanted to spend. /a little? Boy, is that an understatement!/ 😛 😀

Evadman, thanks for that generous offer but that too seems to be over my budget. /read "cheap sob"/ 😛

ericlp, thanks for that link. The Belkin is a possibility but I don't think I want to go the "Ghetto UPS" route. lol

It all boils down to priorities. The occasional lost production and aggravation vs $$$ that could be used to purchase new crunchers. I'm only talking about SETI crunchers ... not some critical function. /I can't believe I just said that ... must go seek counseling/ :Q 😀

 
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