What is the specific gravity of a fully charged lead-acid cell at 80 degrees?

The specific gravity of a fully charged lead-acid cell is typically around 1.280 at a temperature of 80 degrees Fahrenheit. This value is significant because it provides a direct measure of the state of charge of the battery. Lead-acid batteries utilize sulfuric acid and water, and as the battery charges, the concentration of sulfuric acid increases, which in turn raises the specific gravity. A specific gravity of 1.280 indicates that the battery is in a fully charged state, meaning that it has effectively absorbed the maximum amount of charge available.

When measuring specific gravity, it is important to consider temperature because specific gravity can vary with temperature changes. The value of 1.280 at 80 degrees is consistent with standard reference materials for lead-acid batteries. Lower specific gravity readings would indicate a less charged state or dilution of the acid solution, while higher values could suggest overcharging or other issues with the battery chemistry. This specific measure helps users determine both battery health and performance readiness.