Re: Old UPSs

On 30 Mar 2007 at 12:28, scheefjnetscape.net wrote:

> One of the reasons UPSs use sealed lead-acid batteries
is they are 
> located indoors. If you want to use marine or tractor
(or regular car) 
> batteries, they should be located in the proverbial
"well ventilated 
> space". Lead-acid batteries give off hydrogen and
oxygen when charging, 
> a volatile mixture that will linger in any enclosure. I
use 
> batterywholesale.com for replacement SLA batteries
where a 4-battery 
> pack is $200.

Where the pack is kept on perennial "float", such
as a UPS, emissions 
are very low (as witnessed by the tablespoon or so of water
I need to 
add to each cell every 6 months)  The small amount of
hydrogen, being 
much lighter than air, dissipates quickly. (That
"lighter than air" 
aspect is also one of the reasons that I refuse to run
propane into 
the kitchen, as it's heavier than air and will accumulate in
low 
spots).

I suspect one of those "emergency" lamps that are
used in public 
spaces that employ a motorcycle battery generate as much or
more H2.  
The oxygen I don't worry about.  You'd probably generate
more 
hydrogen than the batteries do in a year by using a capful
of Drano 
to unclog a drain.

A little off-topic, but interesting nonetheless is how much
hydrogen 
is liberated by electrolysis.  There were (and perhaps still
are) 
firms offering a "generate your own welding gas"
rig by electrolyzing 
water with potassium hydroxide added.  A 240 volt, 20 amp
rig 
generated enough gas to power a very small jeweler's torch. 
And  
there is very little caloric content in the flame--you could
pass 
your hand through it.  I'll stick with acetylene, thank
you.

Cheers,
Chuck