[doubleg72]

Yeah I'm not sure how such low voltage can overcome the lack of any ions in the condensation in which this could occur.

[dtgriscom]

There's likely contaminants on the surface of the battery which, when water is added, become conductive.

[refurb]

if youve ever rubbed pH paper on an auto battery youll realize there is a lot of residual sulfuric acid on the outside of the case.

That mixed with water is pretty conductive.

[Maursault]

Yeah humidity increases the conductivity of air by reducing the breakdown voltage of air, not by conducting electricity, because it doesn't conduct electricty, because it's an insulator.