Figs. 1,086 to 1,089.—The "Champion" Accumulator; views showing parts and assembly. Fig. 1,086, empty plate; [fig. 1,087], filled plate; [fig. 1,088], complete element, small type; fig 1,089, cell assembled. The plates are of the envelope type and are made thick. The active material is held firmly in place by a covering of lead. A few thick plates are used instead of many thin ones.
The following tests should be made for impurities before the electrolyte is poured in the cells:
Chlorine.—To a small sample of the electrolyte add a few drops of silver solution (20 grains of silver dissolved in 1,000 cu. cm. of water). A white precipitate indicates chlorine.
Nitrates.—Place some of the electrolyte in a test tube, and add 10 grains of strong ferrous sulphate solution. Carefully pour down the side of the test tube a small amount of chemically pure concentrated sulphuric acid. A brown stratum between the electrolyte and the concentrated acid indicates the presence of nitric acid.
Acetic acid.—Neutralize the electrolyte with ammonia, then add ferric chloride. If the solution turns red, and is afterwards bleached by the addition of hydrochloric acid, acetic acid is present.
Iron.—Neutralize a sample of the electrolyte with ammonia; boil a small portion with hydrogen peroxide, and add ammonia or caustic potash solution until the mixture becomes alkaline. If a brownish red precipitate forms, it indicates iron.
Copper.—If copper be present, a bluish white precipitate will be formed when ammonia solution is added to the electrolyte.
Fig. 1,090.—One cell of the Gould storage battery for electric vehicle use. According to the data given by the manufacturers, this cell, containing four negative and three positive plates, has a normal charging rate of 27 amperes; a distance rate of 22 amperes for four hours; a capacity of 81 ampere hours at 3 hours discharge, and of 90 ampere hours at 4 hours discharge. Forty such cells are generally used for an average light vehicle battery.
Mercury.—This is indicated by an olive green precipitate when a solution of potassium iodide is added to the electrolyte, or by a black precipitate when lime water is added.
Platinum.—A rough test for traces of platinum is made by pouring the electrolyte into a cell in which the battery plates are immersed. If gassing take place for some time on open circuit, it is an indication of the presence of platinum.
Ques. What should be done with old electrolyte?