UPS reviews

[BassKozz]

Where can I find UPS reviews ?

I've tried tomshardware/anandtech/google...
I can't seem to find a good site for UPS reviews

After searching for good deals on UPS's, I cam across this thread on FW:
APC Back-UPS Pro 1100VA UPS $119.99 OTD At CompUSA (Also discussed on this thread was a Belkin 1500VA for $130 shipped, and a Tripplite Smart1000LCD for $99 at Costco)

I just purchased the Tripplite Smart1000LCD... I think it was a good deal, but I don't know, for all I know it could be a total POS (I haven't hooked it up to my computer yet). Truth is I haven't built the computer yet... I will be using this on a Intel P4, w/ 8+SATAII HD's in a RAID 5 config (w/ a Antec TruePower 2.0 550W Power Supply) ... so I need a solid UPS to make sure my array doesn't get screwed up in case of a power outage.

p.s. Along w/ reviews, are there any good forums dedicated to PSU discussions ?

Thanks in advance,
-BassKozz

 

[Ice Czar]

few delude themselves into thinking they can actually test a UPS
(unlike the horde of wannabe PSU reviewers)
the equipment involved in both cases generally exceeds the investment a reviwer would want to make.
a full test system easily running into tens of thousands, (you can get close for less however)
since they lack any real numbers, a UPS review would be reduced to "it worked"

example: its common for even good reviewers of power supplies to employ a variac to simulate brownout and surges (and if the reviewer does that its a mark they know what they are about) however, the skew rate isnt very controlable, iterally how fast they can turn the dial, whereas the rate a lighting strike will produce is very fast indeeed, for that they need a programable AC source and those cost.


Tripp-Lite is a well respected brand
and that looks like a good choice for a line interactive in the 1KVA range


as far as forums dedicated to PSUs, youve found one of the few
here its more a focus on power quality and the upgrade path,
another would be
silentpcreview where the focus is generally sound signiture and as lean a system as possible

 

[BassKozz]

Thanks Ice Czar, I never thought about it like that...

but really I am just looking for reviews, as far as...
How do they really hold up under Full Load, 3/4 Load, 1/2 Load, etc? (truth in advertising... you can't trust the box)
Specifically how long will the battery backup keep my computer juiced before it craps out, when the power is out.

I need to have enough time to shut down.
Any ideas?

p.s. whats the "VA" mean anyways? How does it compare w/ watts?
My Antec true power 550watt PSU, if running at FULL load would run approx... 3 mins on the tripplite UPS (according to it's advertising), I just want to make sure this is enough time for my computer to shut-down using the TrippLite software (UPS->COMPUTER via USB)...

Also for $30 extra, I could get the "Belkin 1500 VA Dual Form Factor Small Enterprise UPS - F6C1500-TW-RK "
w/ supposidly supports 1500VA and 830w...
But I have heard not so great things about Belkin...

Which should I go w/ TrippLite or Belkin?
-BassKozz

 

[Ice Czar]

well first you need to tally up what load your putting on it
factor in the inefficiency of the supply for a typical load factor adjust for the power factor of the supply then add the draw of peripherals like a monitor

VA = Volt amps

http://www.marvac.com/fun/power.aspx
http://www.mccordweb.com/newsletters/tech-notes/power-protection-computer.php

assorted cut and paste follows
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Battery Power @ Howstuffworks
Normally, when you buy a pack of batteries, the package will tell you the voltage and current rating for the battery. For example, my digital camera uses four nickel-cadmium batteries that are rated at 1.25 volts and 500 milliamp-hours for each cell. The milliamp-hour rating means, theoretically, that the cell can produce 500 milliamps for one hour. You can slice and dice the milliamp-hour rating in lots of different ways. A 500 milliamp-hour battery could produce 5 milliamps for 100 hours, or 10 milliamps for 50 hours, or 25 milliamps for 20 hours, or (theoretically) 500 milliamps for 1 hour, or even 1,000 milliamps for 30 minutes.

However, batteries are not quite that linear. For one thing, all batteries have a maximum current they can produce -- a 500 milliamp-hour battery cannot produce 30,000 milliamps for 1 second, because there is no way for the battery's chemical reactions to happen that quickly. And at higher current levels, batteries can produce a lot of heat, which wastes some of their power. Also, many battery chemistries have longer or shorter than expected lives at very low current levels. But milliamp-hour ratings are somewhat linear over a normal range of use. Using the amp-hour rating, you can roughly estimate how long the battery will last under a given load.

If you arrange four of these 1.25-volt, 500 milliamp-hour batteries in a serial arrangement, you get 5 volts (1.25 x 4) at 500 milliamp-hours. If you arrange them in parallel, you get 1.25 volts at 2,000 (500 x 4) milliamp-hours.

Power Supply System Integration Part 2: Battery Backup @ Power Electronics Technology

UPS Nonlinear Loads

Most end users are oblivious to the problems encountered when an online UPS interacts with nonlinear load, such as a switchmode power supply. Fig. 3, on page 42, illustrates the interface between an online UPS and a switchmode power supply. The switchmode supply within the host system consumes its current in high amplitude pulses, and as a result overloads the UPS, distorts its output and degrades in performance. This isn't the case if the SMPS has power factor correction (PFC); and in the United States most SMPS don't have PFC.

Repeated measurements under practical conditions show that in non-PFC SMPS, the current peak to rms ratio reaches a crest factor in the range of 2.5 to 3.5. This high crest factor imposes a difficult load for the UPS.

Manufacturers specify UPS capacity in volt-amperes, and set the UPS current limit with resistive loading. This affects the user in two ways: first, the actual power (in watts) that the online UPS can deliver is 75% to 80% of its VA rating. Second, the UPS cannot support a nonlinear load like a SMPS to full power capacity. In fact, it can support an SMPS only rated to 30% to 40% of its capacity. A 1kVA online UPS will only be suitable for backing up a system energized by a 300W to 400W (non-PFC) switchmode power supply. Attempts to draw higher power by the SMPS will severely distort the output of the UPS and may result in shutdown. Some UPSs support nonlinear loads to various degrees, but the above rule is safe to use as a guideline.

The whole idea of generating a high-purity sinewave within the UPS, and then rectifying it within the SMPS is wasteful. A UPS may be deployed to run non-electronic loads, such as lights or motors. However, this is a minor portion of the market for online UPS. Many applications back up computers and telecom devices, as well as instrumentation systems used for critical applications. In all of these applications, the immediate load for the UPS is the SMPS within the systems. Peak current and inrush current are associated with this load at startup. This current of 40A to 80A per SMPS will cause the UPS to shutdown due to overloading, or the UPS must transfer the load to utility to draw its inrush.

Im "upgrading" the importance of active PFC in purchasing, as it does seem to have a great deal to do with not abusing and effectively employing the capacity of an online UPS (and by extention Id assume a line interactive UPS \ SPS when its on batteries, a far more common UPS scheme)


for greater accuracy
use the Calculator in the How to buy a PSU thread to figure up your worse case senerio realworld draw
and then guess at an average or set a threshold you feel comfortable with
then factor in the efficiency of a given supply for the average load on it
(example 250W DC = 244W AC)
then factor in PFC (if you have it dont worry if not decrease the UPS to say 50% of peak draw, which isnt the same as the amp hours, it the total it can supply rather than the length of time)
and finally with a rough estimate of the Voltage AC draw in Watts Convert Watts to VA
then shop for SPS in that KVA range


additional linkage
http://hardforum.com/showthread.php?t=953143&highlight=nonlinear

 

[RainofTerra]

As for the question of whether to go with Tripplite or Belkin, I've never used Tripplite, I almost always use APC, but 4 years ago I got a great deal on a 1400VA Belkin UPS and other than replacing the battery a few months ago I could not be happier. Especially since i got the replacement battery with a 50% off coupon on Belkin's website

-Jeff

 

[BassKozz]

Ice Czar,

Thank you for your detailed and very informative post...
I did my best to get thru it all (very technical, but helpful), and I am still a little lost when it comes to actually calculating the length of time my new TrippLite Smart1000LCD will last under full load, in the event of a power loss...

What I have done is configured my system on takaman's Power Supply Calculator, and here is a link to the output w/ devices selected:
http://takaman.jp/D/?M=PcQEQbdXFSCgHRhXUTbUXk@enHrqHFrHBYbZAZavXHwXAxHAMZ&english

Now just to let you know I have added in some "fluff" to factor in possible future upgrades, but essentially this is what my new Personal File Server will contain.

I was wondering if you could do me a favor and either provide me w/ the formula, or do the calculations on what the estimated duration of time will be in the event of a power loss, using the PSU calculator results above, and this spec sheet for my TrippLite Smart1000LCD.

p.s. I will not be connecting a Monitor to this UPS, I will be using a KVM switch to switch KVM between my current desktop, and this new server.

Thanks, for all the help!!!
-BassKozz

 

[Ice Czar]

I get kind of busy on the weekdays, so this is very guesswork
for starters everything that spins drops to 1\4 of the amps
the full rating is to overcome inertia and spinup,
next its unlikely youd ever be pegging all that is left at the same time

realistically Id say your working wattage will be 100W > 270W
add in inefficiency cof converting from AC to DC and the VAC (Volts AC) would be around
say 150 > 325?
(absolute worse case peak draw for the high end)

I assume your not in Europe, ergo you dont have PFC on that Antec
meaning you likely have a full capacity you can draw with its of near the peak above.
and we havent addded a monitor yet (it however would be a resistive load I think)

a LCD would be say 20 > 50W whereas a big CRT could be 125 > 150W plus


the amp hours on the batteries are expressed as
Full load runtime: > 4 minutes (1000VA / 500w)
Half load runtime: > 14 minutes (500VA / 250w)

what your doing greatly impacts the time you have,
Id say youd have plenty of time to shutdown safely (or automatically if there is software)
but you wont be laughing at hurricanes while your playing the latest games during a bloackout.

Since you have the unit, a little judicious testing is likely in order

 

[BassKozz]

Ice Czar,

Thanks for clearing this up for me !!!

the amp hours on the batteries are expressed as
Full load runtime: > 4 minutes (1000VA / 500w)
Half load runtime: > 14 minutes (500VA / 250w)

Is that including a monitor? As I stated in the lasst post I won't be using a monitor on this UPS, I will have a KVM switch that will switch between this new personal file server and my desktop (which is also backed up via a APC UPS)...

If these figures do Include a monitor how much time could I gain w/o one ?

Since you have the unit, a little judicious testing is likely in order

Once all the parts come in and I build this bad boy, I will do multiple tests to find out an estimate time... but that won't likely be untill 2006 (I am waiting for deals on 4x320gb WD SATA HD's), so I wanted to get a feel for my time limits now, so I know whether or not I should keep shopping for a better UPS.

Id say youd have plenty of time to shutdown safely (or automatically if there is software)

That's all I am really looking for, and there is software for this unit, so looks like I am home free

Thanks again for all your help,
-BassKozz

 

[Ice Czar]

Is that including a monitor?

thats just how they are expressing the amp hours,. so any combination of components that will get you to those wattage figures, but since the PSU isnt Power Factor Corrected its going to place a nonlinear load on the batteries.

Id say the lower range will be likely say 200W then add a monitor, those vary alot do you have an LCD or CRT?
what type and size?

as far as HDDs go they are only going to be drawing about 0.5A +12V
(or expressed another way 12 x 0.5 = 6 watts each) after they have spun up
(24 watts per to spinup) average