They emerged more than 150 years ago; however, lead-acid batteries still remain as one of major energy production resources, especially applied to vehicles. In this paper, it is presented an analysis of lead-acid batteries as energy production facilities in vehicles or another application. A brief historical introduction is presented and addresses the main functional characteristics, as well as, the classifications and applications. Additionally the physicochemical principles involved and thermodynamic parameters are shown. With a multidisciplinary approach, it presents some technical fundamentals in electronics, physics, chemical and engineering, all of them, necessary for the knowledge of this subject.