What is the normal voltage of a single lead acid battery cell?

A single lead acid battery cell typically has a nominal voltage of approximately 2.1 volts when fully charged. This value is based on the electrochemical properties of the lead acid battery, which consists of lead dioxide (PbO2) as the positive plate, sponge lead (Pb) as the negative plate, and sulfuric acid (H2SO4) as the electrolyte. During the discharge and charging processes, the voltage can vary slightly, but the standard nominal voltage recognized is close to 2.1 volts.

When evaluating the other voltage options, it’s evident they do not represent the typical characteristics of lead acid cells. For instance, 1.5 volts is commonly associated with alkaline batteries, while 1.2 volts is typical for nickel-cadmium (NiCd) or nickel-metal hydride (NiMH) batteries. The 2.5-volt option does not correspond to any standard cell type in widely used lead-acid configurations. Understanding these fundamentals provides clarity on battery use and selection based on their characteristic voltages for proper application.