- What happens in a cell as it discharges
As a cell discharges lead sulphate forms on both the positive and negative plates through absorption of acid from the electrolyte. The quantity of electrolyte in the cells remains unchanged. However the acid content in the electrolyte reduces, something noticeable in the change of the specific gravity.
- What happens during charging
During charging the process is reversed. On both plates acid is released, while the positive plate converts into lead oxide and the negative plate into porous, sponge-like lead. Once charged the battery can no longer take up energy, and any further energy added is used to decompose water into hydrogen gas