Concentrated sulphuric acid is generated during all re-charge processes. It
has a higher specific weight compared to diluted acid.
Therefore, it trends to deposit in the lower parts of the cell container
directly after leaving the pores of the active material. One can measure, for
instance, 1.10 kg/l in the upper part of a cell whilst the acid concentration
may achieve 1.40 kg/l in the lower parts.
between