Alvin, there is a simple way to dispel the doubts and I do not have the meters now but here's an idea on how we used to do it. I had 2 meters, both were inline DC/AC. I'd test the loads on AC and comeup with total wattages. Same for the DC side.  If the servers are green mode, then on very minimal load they are powering down to some mode which I think IBM is big on. I checked the IBM specs on the server you listed but they have very few details. Maybe you can share the Power specs and consumption of the servers and whether the servers support any green modes? I've used APC from 10KVA to 1.5KVA before moving to tripplite, practically never seen the scenario you describe below. Lets go a bit deep into this matter, am sure we may learn newer things. For now, I'd still stick to the official APC graph. Asante. :-)

On Tue, Dec 7, 2010 at 9:43 AM, Alvin Jason Ochieng <ajochola@gmail.com> wrote:
@Aki - I agree with you on this atleast on paper.


We are APC Partners. I have been trained by APC and have all the
certs. On this case I found this out
when the client could not afford the 3KVA SMART for their servers.
They opted for that 1.5 kva smart and one of their techies
told me it withstood 3+ hours. I also did not believe till when I was
to supply another server we tested it in the office and it
maintained it !!! from last year I have supplied 50+ factories with
the same SUA1500i. They have frequent blackouts upcountry too
so they always rely on the battery power.

On APC batteries I assure you the genuine ones RBC last btw 3-5 years
!!! But they will cost a pretty penny to replace!!

Me facts !!

Alvin