Elevator backup power [RE-wrenches]

[Phil Undercuffler]

----- Original Message -----
> backup only
> system.  He wants a grid charged battery back up system.

We've done a number of systems like this, although not with an elevator so
far.

> one of the loads he wants backup for is
> an elevator.  He also wants to backup two refrigerators, a home office, an
> electric gate, etc.

Depending upon the duration of the power outage your client expects, this
could require a relatively    large battery bank.  I'm sure those fridges
aren't Sun Frosts, but are they SubZeros?  If he wants to coast through a 4
hour brown-out it's one thing,  but if he wants uninterruptible power for a
couple of days you might consider adding a propane or natural gas fueled
generator for backup charging.  The baseline loads left on in most upscale
houses could quickly deplete even the largest battery bank if no one is home
to perform load side management

> the possibility that the client will choose to get
> in his elevator while the batteries may be low and half way down (or up)
> the inverters conk out on a low battery condition.

I would strongly suggest a TriMetric or E-meter, with the instructions to
keep an eye on the % of full.  Its like the gas gauge in the car.  Or the
level of water in the bucket.  Or like a submarine running off batteries
underwater.  Or whatever analogy your client is likely to understand
intuitively and easily.

> I have thought of putting a battery monitor in his elevator and instruct
> him not to use the elevator below a certain voltage.  I could also
lengthen
> the Low Battery Cut Out time so that the inverters will not shut down on a
> battery sag created by running the elevator.

Most clients, especially those that don't live with the daily cycles of the
sun, are bewildered by voltage.  Imagine:  the voltage is rock steady for a
year, batteries in float.  Grid kicks off, and suddenly the voltage begins
to fall.  The client runs around worried, afraid to turn on a light, sure
that his precious energy is failing when all it is doing is dropping to a
resting voltage.  Or worse yet, the client that thinks that 23.2 volts is
normal on a 24 volt system--don't laugh, I've received that call.  "It's OK,
I get up to at least 24 volts during the day!"  Its a lot easier to
understand 100% or 47% or whatever.  "When the batteries get to 35% get to
the floor you want to stay on for the rest of the outage"

Again, if he's expecting a long duration outage, some sort of bottled energy
for backup charging is a great way to keep the system size manageable.


Enjoy the Sun!

Phil Undercuffler
Positive Energy

"The most beautiful experience we can have is the mysterious....
the fundamental emotion which stands at the cradle of true art
and true science"  --Albert Einstein

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