UPS Batteries (again)

Fri Dec 19 08:02:48 PST 2003

chuck+baylisa at snew.com (Chuck Yerkes) writes:
> I can route the leads to the batteries out the back through
> a couple holes.  I was pondering a big-ass marine deepcycle
> battery.  No more power at once, but for LONGER.*

This is one of my daydreams too.  Why pay close to $100 per 12v 11Ah
gel cell to the UPS manufacturer when much cheaper and larger
car/boat/golf-cart batteries are available.  The thing that is
stopping me from going with the biggest cheapest solutions, a car
battery, is that a wet-cell battery leaks plenty of acid fumes.  Any
sheet-metal nearby starts to rust.  The gel-cells are better but cause
you to take a big hit in both the cost per battery size and in energy
storage per battery size.  Still, one can get some awfully nice
gell-cell golf-cart or wheel-chair batteries.

Then there is the other problem of electrical safety.  High energy
batteries are quite dangerous if something ever shorts their poles by
mistake.  It is a very easy way to start a fire.  In telco buildings
they take pains to move the batteries to a separate room and have
strict rules about what kind of tools and objects are allowed into
that room.  Anything metal that is long enough to accidentally bridge
the two electrical poles has to be completely wrapped in electrical
tape or something else non-conductive.

If I were to add a beefy outboard battery to my ups, I'd be concerned
enough to put both ups and battery in a ventilated cage where I could
be sure that the power wires (and battery connectors) could never be
accidentally cut and shorted by something falling on them.  It would
be a real drag to come home to find the fire dept out front and the
house a smoldering pile of ashes.

> * there are delusions of solar panels and figuring out if the UPS
> can be subverted to just be an inverter - drawing it's power most
> of the time from a gang of batteries which would be charged from
> the sky.

West Marine has a nice set of very efficient DC to AC
inverters/chargers meant for house-boat use.  Their pricing assumes
you are rich enough to maintain a boat.

-wolfgang
-- 
Wolfgang S. Rupprecht 		     http://www.wsrcc.com/wolfgang/
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