"GeoffSchultz" wrote in
ups.com:

they suggested the use of a sealed battery to
avoid the build-up of hydrogen in this space. As is usual, boats are
a series of compromises. I took the advice of people who have far
more expertise than I do in this field.


I don't know about Guatemalan batteries, but wetcell lead acid batteries,
either those "sealed" (which all have gas vents to prevent pressure
explosions) or liquid wetcells, haven't gassed hydrogen during NORMAL
charging since manufacturers stopped using antimony grids to hold up the
soft lead in the grid. Modern lead-acid batteries use an alloy that
prevents gassing by the grid structure and reduces local battery action
to nearly zero. (The old batteries used to discharge themselves quite
rapidly because the antimony and lead formed a weak battery with the
electrolyte that was shorted because the antimony and lead were bonded
together. This ate the electrolyte over a short time. Remember "dry
charged" batteries way back? That was why.)

BOATERS, as a charging group always in a terrible hurry to speed up a
very slow chemical reaction (charging) against all the rules of chemistry
and physics, create hydrogen gas by hugely overcurrenting their battery
banks with massive alternators, giant chargers, overvoltage charging,
etc. in many ways. This causes a chemical reaction at the surface of the
plates that breaks down the electrolyte's diluting water into oxygen,
which creates lead-oxide coating on the plates, plus hydrogen gas, which
vents, no matter whether the electrolyte is a jelly, soaked in a guaze
AGM rolled up between the plates or in liquid solution. Of course, this
consumes the electrolyte's water supply, which requires replenishing.
This is not a problem on batteries charged properly, SLOWLY, which don't
bubble at all because their hydrogen and oxygen ions recombine back into
water not being driven hard apart by the overcharging.

All boaters know you can charge the house batteries in 20 minutes engine
time if you charge them at 250A, right? Your manufacturer's advise took
this into account...(c;

Larry
--
http://www.youtube.com/watch?v=fEJmc...elated&search=