Re: OT: UPS

On Sun, 23 Aug 2009, Andy Civil wrote:

> Charles MacDonald wrote:
>> The UPS will also have an watt-Hour rating, say your system draws 200 w, 
>> and the UPS is rated for 400Watt-hours  So it could run the computer for 2 
>> hours.
> Your math is perfect, but your hopes are a bit high. The UPSs I've seen last 
> long enough to shut things down cleanly, and that's about it. 
>
> The consumer grade UPSs are not that good. They quote the VA as though 
> they're watts. The 650VA will actually supply 390 watts. It will run at that 
> level for 4 minutes, or more realistically, 13 minutes at half load. What you 
> really care about is that after three years use, when the battery isn't so 
> good, it will still last long enough to 'shutdown now' LOL!

Lots of good discussion.

Coincidently, I tested my APC Back UPS RS 1000 just the other night. 
Here's what the linux apc tool reports on its state: 
----------------------------------------------
APC      : 001,038,0979
DATE     : Sat Aug 22 16:06:29 EDT 2009
HOSTNAME : <del>
RELEASE  : 3.14.4
VERSION  : 3.14.4 (18 May 2008) debian
UPSNAME  : <del>
CABLE    : USB Cable
MODEL    : Back-UPS RS 1000 
UPSMODE  : Stand Alone
STARTTIME: Sat Aug 22 12:45:25 EDT 2009
STATUS   : ONLINE 
LINEV    : 122.0 Volts
LOADPCT  :  17.0 Percent Load Capacity
BCHARGE  : 100.0 Percent
TIMELEFT :  50.0 Minutes
MBATTCHG : 5 Percent
MINTIMEL : 3 Minutes
MAXTIME  : 0 Seconds
SENSE    : Medium
LOTRANS  : 097.0 Volts
HITRANS  : 138.0 Volts
ALARMDEL : Always
BATTV    : 27.3 Volts
LASTXFER : Automatic or explicit self test
NUMXFERS : 0
TONBATT  : 0 seconds
CUMONBATT: 0 seconds
XOFFBATT : N/A
SELFTEST : NO
STATFLAG : 0x07000008 Status Flag
MANDATE  : 2003-11-28
SERIALNO : <del> 
BATTDATE : 2001-09-25
NOMINV   : 120 Volts
NOMBATTV :  24.0 Volts
NOMPOWER : 600 Watts
FIRMWARE : 7.g8 .D USB FW:g8 
APCMODEL : Back-UPS RS 1000 
END APC  : Sat Aug 22 16:06:30 EDT 2009
----------------------------------------

I noticed my BATTDATE was 2001-09-25, almost 8 years ago. Mind you the 
MAN(ufactured) date is 2003-11 (almost 6 years ago). So I decided to do an 
extended discharge test, keeping in mind that deep-discharging lead-acid 
cells is harmful to them.

I discharged to 50%, which is still really too much still. By the reported 
fractional discharge versus estimated time remaining I figured my battery 
had only lost <10% of its new capacity, after 6 (or 8) years on standby. I 
was surprised. But maybe it's not linear and I would find the "100%" time 
falls short.

Googling the data for my UPS, I came up with this:
http://www.apc.com/products/family/index.cfm?id=23#anchor1
It's a cute dynamic page that lets you set the load, and it shows the run 
time for various UPS. Might give you an idea, anyway.

This static table gives an idea of the run time versus load and capacity 
for various APC UPS:
http://www.apc.com/products/runtime_for_extendedruntime.cfm?upsfamily=23

My server uses 88W according to the power meter it is plugged into right 
now. (Core 2-8400 CPU, 8 GB RAM on Asus P5E mobo, 2 drives in RAID1, and a 
low end video card) I have been trying to reduce power usage, therefore 
the power meter on it this moment.

I have two of these APC UPS, which I bought at Future Shop or Best Buy, on 
sale (I think about $150 ea.). I am really impressed with their quality 
and the capabilities of the linux apcupsd software that monitors them.
For one thing, i reall like getting that huge report about their status 
:-)

Brett
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