RENEWING DRY CELLS.

Auckland Star, Volume LXV, Issue 267, 10 November 1934, Page 7 (Supplement)

RENEWING DRY CELLS.

One is often asked whether it is possible to renew dry cells such as are used in electric torches, etc. Whilst there is no practical plan of restoring a worn-out cell to its original strength, a considerable amount of current may etill oc secured if the cells are treated in the following manner. If the .cell lias a cardboard container, remove this, and then drill about 20 holes in the zinc covering. holes should be about I'm in diameter, and should be drilled not more than deep. No attempt should be made to punch the holes with a nail or other pointed implement. If this were done part of the zinc would be pushed into the cell, and complete failure in the matter of' renewal would be the result. The beet plan is to uee a bradawl, pressing the too! in a uniform manner whilst the hole is worked out. Distribute the 20 holes well over the surface of the cell. '..-:

The next step is to prepare a saturated solution of sal ammoniac (ammonium chloride), a chemical which is quite cheap and can be obtained from any chemist. About three-pennyworth \Vill be enough, and thie should be dissolved in a jar of water until the liquid refuses to take up any more. The jar should be of such a size that it will accommodate the cell. Now place the cell in the jar and allow it to absorb the sal ammoniac solution for several hours. Then remove the cell, dry it thoroughly, and plug the holes witii softened candle wax. The solution described is sufficient to treat several worn-out cells, so the plan described is "cry inexpensive, and each re newed cell will be found to deliver quite a lot of current. For the pur pose of laboratory experiments, oil cells can \be secured from garages, taken from stationary gas engines, motor boats, etc.