[ale] OT: APC wattage

[Dow Hurst]

My experience has shown me that if you expect to run off your batteries 
for long enough to start really heating the battery that you should get 
a large enough UPS to not use more than 50% of the available wattage.  
So, a 450VA APC SmartUPS will certainly keep my SGI O2 with external 
SCSI CDburner alive for ten minutes, maybe 15 minutes.  However, the 
batteries will have overheated and started to degrade.  When I had 90% 
of an APC capacity used in one situation, the battery literally melted 
it's case and deformed significantly.  So I always try to ride around 
50% of UPS capacity for my load when on battery.  The batteries will 
last longer that way too!

At home I got a CyberPower 1500VA for two Athlon PCs, three 17" 
monitors, a Pentium firewall, switch and DSL modem, and a HP OfficeJet.  
I am at 40% capacity when everything is running.  It has a builtin fan 
to help cool the batteries during blackouts.  It also adjusts voltages 
on the fly like a APC Smart UPS.  I just couldn't afford the APC 1400 
size so went with this brand.  It is holding up so far but hasn't been 
in service for a whole year yet.
Dow


John Wells wrote:

>I'm in the market as well, but I'm a bit shaky on what APC wattage
>actually indicates.  For example, I have four pcs running 24/7, and the
>power supplies break down to:
>
>1 350W
>1 300W
>2 250W
>
>Totaling 1150W if all were to *max* their wattage at a given time.  Now, a
>cursory look at APCs show they are across the board regarding
>wattage...but I'm not sure there's a direct correlation to the apc's
>wattage and the pc powersupplies it can support (if there were, you'd be
>spending megabucks in a multi-pc household).
>
>So, how do I get a fairly good idea of how much APC muscle I need?  I
>don't think I need more than 20 minutes or so of battery power (and even
>that seems a bit much).  More interested in dodging hiccups and the like,
>and the occasional blown fuse.
>
>Thanks for the insight.
>
>John
>
>
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-- 
__________________________________________________________
Dow Hurst                  Office: 770-499-3428
Systems Support Specialist    Fax: 770-423-6744
1000 Chastain Rd. Bldg. 12
Chemistry Department SC428  Email:   dhurst at kennesaw.edu
Kennesaw State University         Dow.Hurst at mindspring.com
Kennesaw, GA 30144
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