As is typical for UK websites here's an excellent article on batteries
with pictures. They're not stingy with good information. :-)
Despite the low current attainable with 12 volts applied
to the cell the approximately 0.6 square meter Metal-Water
interfaces with about 3.0 volt bias on the plates it acts like the
"Self Discharge" effect in storage batteries that generates H. H2,
O, O2, and OH gases.
