BATTERY EFFICIENCY

Evening Star, Issue 22229, 6 January 1936, Page 11

BATTERY EFFICIENCY

AVOIDANCE OF SULPHATION One of the principal causes of the deterioration of a storage battery is the formation of lead sulphate, which, in the course of time, and specially when the cells are not kept well charged, forms insoluble deposits which replace the active material in the plates of the cells. Sulphation is a normal process in every storage battery, for during discharge the sulphuric acid in the electrolyte, which consists of distilled water and chemically pure sulphuric _ acid, combines with the active material on the plates, and lead sulphate is produced. When the cejls are recharged either by the generator of the car or at the service station, the process is reversed, the chemical action caused by the charging current desulphates the plates; and the density of the electrolyte is restored. The right proportion of acid to distilled water in the electrolyte Las been carefully determined by scientists, and when it is appreciated that the everyday work of each cell is one of constant chemical change, and that the specific gravity of the solution as ascertained by the familiar battery hydrometer, is, as a rule, a dependable indication of the condition of the cells, it will he understood that the adding of more acid in order to “ pep up ” a battery is futile. If the level of the liquid his fallen because of accidental spilling or leakage, then the cells may be topped up with a solution of the correct specific gravity; but ordinarily only distilled water /would be used. The battery should be examined regularly and water added to keep the level well above the tops of the plates. Many compounds which were said either to prevent sulphation or to revive a worn-out battery have been marketed from time to time, hut few, if any, have been so efficacious that they have Won lasting popularity. It is claimed that a distilled mixture discovered by an Australian scientist, and which is now; being produced in commercial quantities, will prevent sulpliation, and will have no harmful effect on the cells. The solution is added to the electrolyte, the amount being about two fluid ounces for a six-volt battery. Its ingredients have not been disclosed, hut it is said that tests conducted at the University of Melbourne and by experts of several public departments have shown that it fulfills its purpose, and is in no way detrimental.

The manufacturers say that the filling of the pores of battery plates with hard sulphate crystals has been one of the greatest difficulties to be overcome. The particles of active paste in the plates become separated by sulphate and crystallisation causes expansion, sb that there is a crushing action which ultimately causes the paste to loosen and disintegrate. As this expansion occurs, particles of the paste form into groups, and these become isolated from each other hy sulphate crystals, so that the acid electrolyte is shut off from the inner areas of active material forming the groups, and the cell may fail, although there may be still an adequate quantity of active material.

The compound referred to will, it is stated, _ “ hold the sulphate permanently in solution, instead of allowing it to crystalise and also soften any hard sulyhate crystals which have previously formed between the particles of paste on the plates, so that the electrolyte can come into contact with the paste that has become isolated, thereby reviving the capacity of the cell.”