[Tfug] UPS sizing

[Bexley Hall]

Hi, John,

--- On Thu, 1/1/09, johngalt1 <johngalt1 at uswest.net> wrote:

> From: "Bexley Hall" <bexley401>
>
> > When I lived in the midwest, power outages were a
> > frequent occurrence (e.g., sometimes twice a month).
> > As such, I relied on a *big* UPS (3.5KVA with just
> > about an hour uptime at full load) since it would
> > allow me to keep working *through* the outage.
> 
> Did you need 3.5 kva?

No!  I had complained to a friend about all the (long)
power outages I was experiencing.  He said he had the
*perfect* UPS for me (I didn't have one, at the time).

[As an aside, I should state that I have a certain class of
friends that seems to *delight* in trying to "overwhelm" me.
E.g., asking for a spare telephone got me my first PBX;
asking for a flashlight got me a Thor-X (google it); asking
for a *light* (cigarette) nearly cost me my eyebrows from
the oxy-acetylene torch!  :-(  ]

I showed up at his place.  He went away for a minute -- and
came back driving a back-hoe with this monster tucked in the
bucket!  And a grin that started from *behind* one ear and
wrapped all around to behind the *other* ear.  :-/  I had
to disassemble the damn thing to get it off truck and into
my basement  :-/

> If someone else said that, I might think there is confusion
> between power requirement and uptime requirement. Unless you
> have little consumer grade units, it is pretty easy to add
> more packs for longer uptime.

The advantage of this unit was the size of the built in battery
pack -- the primary for the inverter ran at 120VDC (i.e., *ten*
12V batteries in series).  The *secondaries* were wound with
#8 AWG!

> > That monster (it was almost the size of a washing
> > machine) is no longer with me (it would have cost
> > an arm and a leg to ship it!) -- and I probably have
> > no place to *keep* it (since the garage would beat
> > the hell out of it in the summer).
> 
> Sounds like old technology.

Well, it's been 15 years or more... :>

It was an amazing UPS, though!  I could run the refrigerator
off of it!  You could even run a circular saw directly off
the output (I suspect this would fry most new UPS's -- even
those "big" ones -- or, if not, would fail to start the saw).

> > Since power outages here seem to be relatively
> > infrequent (I think less than one a year in my
> > neighborhood), it seems silly to invest the $$$ and
> > space in a similar beast.
> >
> > Rather, it seems like I'm better served by a small
> > UPS at each machine that is just big enough to
> > provide an orderly shutdown (saving work in progress)
> > in the event of a power outage (and, to tide me over
> > in those occasional dropouts).
> >
> > Does this seem in line with what others have done?
> 
> I settled on 1.5 kva smart UPSes at each place in the house
> where uptime is needed. None of my equipment approaches
> that power requirement.

I'd imagine these are pretty big (physical size), though?
What sort of experiences do you have with outages in your
neighborhood?

--don