1. Colour of the plates: The colour of the (+ve) plate is dark chocolate brown and the (-ve) plate is grey.
2. Voltage Percell: The voltage/cell is about 2.6 volt when fully charged.
3. Specific Gravity of the Electrolyte: When fully charged, then the sp. gravity is constant and at about 1.23.
4. Gassing: Liberation of oxygen causing gassing for fully charged cells.