Effects of Lithium Sulfate and Zinc Sulfate Additives on the Cycle Life and Efficiency of Lead Acid Batteries

The influence of lithium and zinc sulfate additives on the cycle life and efficiency of a 2 V/20 A H lead acid battery was investigated. Charging and discharging processes (cycle) were carried out separately for dilute sulfuric acid electrolyte, sulfuric acid-lithium sulfate electrolyte, and sulfuric acid-zinc sulfate electrolyte solutions for one (1) hour each. The voltage after 30 min of the charging process yielded 2.30 V for dilute H₂SO₄, 2.74 V for H₂SO₄ + Li₂SO₄, and 2.90 V for H₂SO₄ + ZnSO₄ solutions. A load of 6 V, 10.3 W incandescent lamp was applied, and after 30 min of the discharge process for each electrolyte, the voltage was 1.10 V for H₂SO₄, 1.90 V for H₂SO₄ + ZnSO₄, and 1.30 V for H₂SO₄ + Li₂SO₄. A calculated efficiency of 77% for H₂SO₄, 74% for H₂SO₄ + ZnSO₄, and 85% for H₂SO₄ + Li₂SO₄ solution was obtained. The cycle test is evidence that the addition of lithium sulfate salt improved the cycle life and efficiency of the 2 V/20 A H lead acid battery, while zinc sulfate offered no significant improvement. The cycle life of a battery increases with decrease in acid concentration, longer discharge time, and increase in efficiency.