Document 9J19nrzZoQGeNOL2mJx91yax6

s CHAPTER 2/THE BATTERY, CHARGING, STARTING, AND LIGHTING SYSTEMS THE BATTERY The typical automotive lead-acid storage bat tery stores electrical energy in chemical form and releases it when required by the automobile. It supplies the energy to drive the starter motor, and powers the ignition system when the car is starting. If the charging system fails, the battery may be called on to provide all the electricity needed by the car. Unlike most of the smaller batteries that power flashlights and toys, an automotive bat tery is rechargable. The energy that's "taken out" of the battery can be "put back in" by the car's charging system. How A Battery Works VENT PLUGS TAPERED TERMINAL The primary ingredient of the active material is lead, although positive plates and negative plates are made with a slightly different formu lation. Positive and negative plates are alter nated, with separators placed between them for insulation, to form a cell. A connection is made between all the positive plates and between all the negative plates in each cell of the battery. Each cell can produce a maximum of 2.1 volts. These cells are welded together in series to create a battery of the desired voltage. A 6-volt battery, for example, has three cells, and a 12-volt battery has six cells. Once all the battery cells are welded together and placed in the battery case, the electrolyte, or acid, is added. Then the battery is given its initial charge, which establishes its electrical performance. During this process, the positive and negative plates undergo a chemical reaction that changes the active material into lead diox ide and lead respectively, storing up the electri cal energy in a chemical form. POS. NEG. PbO 2 + Pb + 2H SO 24 DISCHARGE CHARGE PbSO + PbSO +4 2H O 2 POS. NEG. (Figure 9) Chemical reactions within a lead-acid storage battery. When the battery is in use and discharging, the positive and negative active material tend to become more similar, reacting with the sulfate in the acid to form lead sulfate. Then as the alternator recharges the battery in the car, it again stores up electrical energy converting the active material back to lead dioxide and lead. (Figure 8) Interior of a Battery. The backbone of a storage battery is the grid, a framework that supports the electrically active material in the battery, which is arranged in plates. The grid supports both positive and #:egative active material, and provides a conduc:or path from the plate terminals where the cables are connected. Types of Batteries Batteries fall into three general categories: wet, dry-charged, and moist-n-charged. Wet batteries are delivered complete from the factory, full of electrolyte and already charged. The biggest advantage of the wet battery is that it can be installed without having to add elec trolyte. The disadvantage, however, is that it has l