An Electronic Hydrometer

This paper presents an electronic hydrometer that has been designed to provide a reliable measure of the specific gravity of electrolyte inside a stationary lead acid battery. The problems associated with this type of measurement are discussed together with an overview of some practical solutions. A prototype is described which incorporates some practical advantages over many currently available designs including automatic electrolyte temperature compensation and low electrolyte level warning. The hydrometer has been tested for accuracy and promises a wide range of applications in the stationary battery field, including telecommunications applications; in the laboratory and in the electric vehicle field.