Lead acid batteries are used for starting, lighting, and ignition (SLI) services on automobiles and trucks. In addition, lead acid batteries provide power for automobiles, forklifts, submarines, and almost all other motive vehicles. A lead acid battery is made up of plates, lead, and lead oxide with a 35% sulfuric acid and 65% water electrolyte solution.  Lead acid batteries represent almost 60% of all batteries sold worldwide.  

Lead acid batteries are noted for their ability to withstand harsh environments, and are often used as a back-up power sources for primary battery or electrical power failure. A lead acid battery use a simple set of reactions to provide energy.  All styles of lead acid batteries use the same active materials.  The positive electrode is lead dioxide (PbO₂), which is converted to lead sulfate (PbSO₄). The negative electrode is a spongy metallic lead (Pb), which is also converted to lead sulfate (PbSO₄). The electrolyte is a dilute mixture of sulfuric acid that provides the sulfate ion for the discharge reactions.

Lead acid batteries are used for starting, lighting, and ignition (SLI) services on automobiles and trucks. In addition, lead acid batteries provide power for automobiles, forklifts, submarines, and almost all other motive vehicles. A lead acid battery is made up of plates, lead, and lead oxide with a 35% sulfuric acid and 65% water electrolyte solution.  Lead acid batteries represent almost 60% of all batteries sold worldwide.  

Lead acid batteries are noted for their ability to withstand harsh environments, and are often used as a back-up power sources for primary battery or electrical power failure. A lead acid battery use a simple set of reactions to provide energy.  All styles of lead acid batteries use the same active materials.  The positive electrode is lead dioxide (PbO₂), which is converted to lead sulfate (PbSO₄). The negative electrode is a spongy metallic lead (Pb), which is also converted to lead sulfate (PbSO₄). The electrolyte is a dilute mixture of sulfuric acid that provides the sulfate ion for the discharge reactions.

Lead acid battery groups are sized by the Battery Council International (BCI). The BCI provides a group number to define the physical characteristics of lead acid batteries. These characteristics include maximum dimensions, voltage, post configuration, and the type of terminal used. There are three common types of lead acid batteries: flooded or wet, absorbed glass mat (AGM), and gel cell.

Flooded or wet lead acid batteries and AGM lead acid batteries are commonly available. Wet or flooded lead acid batteries have electrodes or plates immersed in an electrolyte. Because gases created during charging are vented to the atmosphere, distilled water must be added occasionally to bring the electrolyte back to its required level. The most common example of a flooded lead acid battery is the 12V automobile battery. Absorbed glass mat (AGM) lead acid batteries are a type of sealed lead acid or valve-regulated lead acid (VRLA) batteries in which the electrolyte is immobilized. A highly porous and absorbent microfiber glass mat, partially-filled with electrolyte of the desired specific gravity, is used as the separator.

Gel cell lead acid batteries are also available. Gel cell lead acid batteries are a type of sealed lead acid or VRLA battery. In gel cell lead acid batteries, fumed silica is added to the electrolyte, causing it to harden into a gel.  On subsequent charges, some water is lost. This dries the gel until cracks and fissures develop between the positive and negative electrodes. The cracking provides a path for oxygen recombination. Other types of lead acid batteries are available. Some varieties of lead acid batteries are rechargeable.