But won't an unsealed (i.e., NOT "maintenance-free") battery lose water
by evaporation even if it's not overcharged? Otherwise why the need to
check the electrolyte level regularly?



Not meaning to get this tread off on a tangent, but the above comment
prompts me to point out that even "maintenance free" batteries AREN'T,
necessarily. On many occassions I have found it necessary to peel back the
paper cover on automotive maintenance free batteries, remove the exposed
cell caps, and add water, especially after a year or two operating in a hot
climate. I don't believe marine type batteries would be any different in
this regard.


Ed K7AAT