[Fig. 101] illustrates a storage battery with a section of the cell retainer case removed to show the location of the cells, their respective order, terminal posts and connections. A section of the cell jar, has also been removed to show the core, which consists of a set of positive and negative plates. The positive plates are inserted between the negative plates and are held in this position through their respective connections to the positive and negative terminal posts. The cell retainer-jars are made of zinc or rubber, and contain an acid and water solution called electrolyte into which the core is entirely immersed.
The Positive and Negative Plates.—The plates are held from direct contact with each other by a wood or rubber separator. These plates are formed with small sectional compartments called grids, into which a lead compound in paste form is pressed. The positive plates are made of lead oxide (zinc), and are dark gray in color, while the negative plates are made of pure lead, and are light gray in color.
Cells.—The cells are connected up in series, that is, the positive terminal post of one cell is connected to the negative terminal post of the next cell, forming a direct path through the cell arrangement. Each cell will retain a two-volt pressure until fully discharged. The voltage of a battery is determined by adding the number of two-volt cells that it contains.
Amperage.—The standard type of storage battery shown in [Fig. 102] is composed of three two-volt cells which form a six-volt unit of sixty ampere hours, which means that a fully charged battery will deliver one ampere per hour for sixty hours. This, also, is about the rate of amperage consumed by the modern battery ignition system.
Electrolyte Solution.—The electrolyte solution is composed of a mixture of one part of sulphuric acid added to four to six parts of water. This solution is poured into the cell through the filler cap, until the plates are covered from one-fourth to one-half inch in depth as shown in [Fig. 102].
Care should always be exercised to keep the air vent in the filler cap free from grease and dirt in order that the gases formed through evaporation may escape.
Battery Charging.—The cells are charged by passing a direct current through them, which causes a chemical action to take place as the current flows in, changing the nature of the positive and negative plates, thereby retaining a current force equal to the difference of the changed nature of the plates. The battery is entirely discharged when the plates become alike in nature.
| Unscrew this Cap | |||
| Fill up to this Point | |||
| SOLUTION | Don’t fill above this Point | ||
| PLATE | |||
Fig. 102. Storage Battery, Sectional View