It is quite clear that these quantities are not the same from one another. Despite this, they are often used interchangeably and it is key to clearly distinguish between them. Density is a measure of mass per unit volume. While on the other hand, specific gravity is a measure of the relative density of a fluid with respect to. A battery produces electrical power through chemical reactions in it. The concentration levels of sulfuric acid in the electrolyte changes as the. When the measured specific gravity of the battery is measured and is found to be below 1.26, it could mean any of the following: 1. The battery is damaged through sulfation or is old and is at the end of its useful life. Sulfation. The density of water maximum at 40C or 390F. The measure measurement of specific gravity of the sulfuric acid and the battery acid is assumed to be taken at the ideal temperatures.