Dear Mr. Haiges:

The proper terms are "electrolyzed" (not "hydrolyzed") and "electrolysis" (not "hydrolyzation").

At Cathode(-):
Pb + SO4(-2) = PbSO4 + 2e(-)

At Anode(+):
PbO2 + SO4(-2) + 4H(+) + 2e(-) = PbSO4 + 2H20


Or the overall reaction can be simplified as:

PbO2 + Pb + 2H2SO4 <----> 2PbSO4 + 2H2O


Water H20 is needed for the ionization of sulfuric acid H2SO4 while water itself is also partly electrolyzed (aka. decomposed) by electric current into H2 and O2 (which in liquid form are the fuel stored in the multi-stage boosters of NASA shuttles!, very explosive stuff).

I believe that the water loss in auto lead-acid batteries is mostly due to evaporation (through vents) rather than to electrolysis.

As you can see from the simplified reaction, the chemical reactions occurring in lead-acid batteries are completely REVERSIBLE, which means that lead-acid batteries will theoretically last forever, as long as you replenish them with enough DISTILLED water and electrical charge (prolonged discharge will cause complete and irreversible sulfation on the lead plates' surface). However, in real life, minerals and chemicals in not-so-distilled water (causing corrosion), sulfation due to discharge, unchecked loss of water, extreme vibrations etc... all are factors reducing the working lifespan of auto lead-acid batteries.

Eric