Translations:Fonctionnement, entretien et régénération de batteries au plomb/69/en

During discharge, lead sulphate (PbSO4) forms on the positive and negative electrodes. If the battery remains discharged, this lead sulphate crystallizes and hardens. Once crystallized, it can no longer turn into sulfuric acid when charging the battery. This causes the battery capacity to drop: "it no longer holds a charge" it is a weak battery/it is a dead battery.