Long-term (hours+) solution for power outage: PBX, lights, and computers

[Ben Scott]

On 8/31/06, Ted Roche <tedroche at tedroche.com> wrote:
> A client suffered a five-hour downtime recently, and has been looking
> for a reasonably priced solution.

  Define "reasonably priced".  What your client is asking for does not
come cheap.

> The client would like to keep a half-dozen computers, LCD screens and
> a laser printer or two running for a 4- to 6-hour period.

  The laser printers are going to kill you.  The computers and the
LCDs can be adapted to run directly off DC/battery, which can gain you
a lot.  But the fuser in a laser printer is essentially a small space
heater, and sucks power like crazy.  Can your client give up the
requirement to keep the laser printers running?

> He's working out of leased office space, and a generator or major structural
> changes are unreasonable.

  As I know you know, a large battery plant is a non-trivial thing.
In addition to everything Bill Sconce already pointed out, there may
be fire code requirements as well.  I know the battery plants in telco
COs are truly scary in their potential for destruction.

  So regardless of whether you go with a generator, a large battery
plant, a flywheel, or a giant mutant hamster in a wheel, I think you
are going to face problems in the area of physical plant.

> For example, each computer has its own small APC UPS, so there would
> be two sources of battery power in series.

  All the UPS vendors I am familiar with say "Don't do that" --
generally very loudly.  It's also rather inefficient.  Inefficiency is
the enemy of economy and compactness, which you have give as goals.
So you're probably best off getting rid of the small UPSes and going
to one big solution.

> http://www.sentrypowertechnology.com/

  From their site: "The systems do not produce heat..."

  Neat!  I wasn't aware the Second Law of Thermodynamics had been repealed.  ;-)

-- Ben