BL> No they're not sealed. The gas is hydrogen which leaks through
BL> solid steel, and oxygen which combines with almost everything.
BL> What happens is that they fizz, and eventually dry out. You cna
BL> brign a gelcell back to life by drilling a tiny hole and
BL> squirting water in with a syringe.

JB> they stick a catylist in there that turns some (hopefully most)
JB> the fizz back into water.

 Eh? A catalyst that turns OH ions into water? Where does the
energy come from? Sounds like a good one to me.

 They do dry out, btw. Quite often... about five years.

JB> They do the same in "sealed" lead acid batteries

 No they don't... unless you mean something else. The low-maintenance
lead-acid car batteries just use heavier lead plates.

JB> ISTR that the catulist reduces the life when comaprted to a
JB> properly maintained regular lead acid battery.

 (grin) A gel cell has less capacity than a cell using sulphuric
acid becasue there is a natural limit in the (dry) electrolyte . I
love phraseslike "properly maintained." What destroys a lead-acid
battery faster than anything is deep cycling (running it flat between
charges) or overcharging at a high voltage, whether gelcell or not.
Topping it up with water is the least of your problems.

Regards,
Bob
  



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