Old UPSs

Chuck Guzis cclist at sydex.com
Fri Mar 30 12:43:54 CDT 2007


On 30 Mar 2007 at 12:28, scheefj at netscape.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




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