1995-1997 Kawasaki 750ZXi-900ZXi Jet Ski Repair Manual., Page 19Get this manual
GENERAL INFORMATION 1-13
Pb Negative active material (charged state) (pbo)
12 Oxygen generated from positive plate
(PbO) Negative active material
H2S04 Electrolyte
PbS04 Negative active material (charged state)
Thus, the negative plate is made as not to get fully chargedEven if the overcharge continues, the oxygen gas generated inside the battery IS absorbed by the negative plate, process called oxygen cycle, which keeps water loss theoretically at nil, and allows the battery to be sealled
(IV) Filling the Battery with Electrolyte