Gel cells combine sulfuric acid with silica to form a gelatinous consistency between the plates. AGMs use a glass microfiber separator that absorbs liquid electrolyte. Calcium strengthens the lead plates, making them easier to handle and cheaper to make. Calcium, however, increases grid corrosion and growth in the positive electrode, which eventually causes AGM and gel cell batteries to fail. These calcium-alloyed plates usually are thicker to offset the increase in positive grid corrosion and grid growth.
Temperature also influences battery performance and longevity.
Higher temperatures reduce battery life by increasing chemical reactions within the battery, which contribute to cell dry-out and positive electrode grid corrosion. In a cable TV environment, temperature changes are especially significant because most cable power supplies must function outside, where they are constantly exposed to weather-driven temperature changes. But eliminating calcium is only half the answer. Pure lead plates often have a limited and unpredictable cycle life because, under certain conditions, they promote the development of a resistive interfacial barrier between the positive grid and the active material. This resistive layer can impede the battery's recovery from deep discharges.