What does specific gravity measure in relation to electrolytes in a wet cell battery?

Specific gravity in relation to electrolytes in a wet cell battery measures the density of the electrolyte solution compared to the density of water. It provides crucial information about the concentration of sulfuric acid in the solution, which is essential for the battery's operation. The specific gravity is typically measured using a hydrometer, and as the state of charge changes, so does the specific gravity: a higher specific gravity indicates a higher concentration of sulfuric acid, which corresponds to a better charge in the battery.

Understanding specific gravity allows one to determine the battery's state of charge without needing to apply a load or measure voltage directly. For instance, a fully charged lead-acid battery will have a higher specific gravity reading than when it is discharged. Therefore, this measurement is critical for maintaining battery performance and longevity.

The other aspects, such as voltage output, conductivity, or temperature, do not directly tie into what specific gravity measures; they relate to different properties or conditions of the battery rather than the composition of the electrolyte solution itself.