Types of Lead Acid Batteries
- Lead-acid batteries have one or more sections, called "cells." Each cell contains a positive electrode --- made of lead dioxide --- and a negative electrode --- made of sponge lead --- that connect to the lead terminals on the outside of the battery. An electrolyte solution of water and sulfuric acid surrounds the electrodes; a separator of porous plastic or fiberglass keeps them from touching one another and causing a short circuit. A container, often of polyethylene or another kind plastic, houses the battery.
- The most common type of lead-acid battery is the starter battery --- also referred to as the starting, lighting and ignition, or SLI, battery. Its cells hold a number of thin electrode plates, which enable the battery to generate the brief but intense jolts of electricity needed to start internal-combustion engines, such as those of automobiles and lawn mowers. The 12-volt car battery is perhaps the best known of this type. Because electrolysis separates the electrolyte's water into hydrogen and oxygen, water must be added to starter batteries periodically to prevent them from drying out.
- Whereas starter batteries produce short bursts of electricity, deep-cycle batteries are able to maintain a continuous electric current for an extended period. So named for their ability to tolerate repeated deep discharges --- up to 80 percent of their capacity --- they have thicker electrode plates than starter batteries do. Common uses of this type of battery include powering lights in RVs and electric motors.
- Industrial batteries are deep-cycle batteries suitable for industrial applications. One kind of industrial battery, known as a traction battery, powers electric vehicles, such as fork lifts. Another kind, a stationary, or standby-power, battery, has two purposes: storing large electrical loads for use when electrical demand is high or serving as a backup source of electricity during power outages. Some stationary batteries, called "sealed batteries," have vents or valves that regulate the gas pressure within them. This feature causes the oxygen and hydrogen produced during electrolysis to recombine into water, making it unnecessary to replenish the battery's water.
