The positive plates may be allowed to dry out, but the negatives should be kept in distilled water and not allowed to dry out in the least. They should not be kept this way indefinitely, but should be assembled and charged as soon as possible.
Do not attempt to repair groups or plates which have lost as much as half of the active material in wear, or which have the active material disintegrated and falling out. Such plates should not be used. This does not apply to small bits of active material knocked out mechanically and amounting to an extremely small percentage of the whole. Abnormal color indicates possible impurity, and such plates should be washed and used with caution. Badly cracked or broken plates should be replaced with new plates or plates from other groups.
Before new negative plates are used they should be fully charged. (See Charging Negative Plates, page 484.)
Always use new wood separators when assembling repaired cells.
When cells have been operated reversed in polarity to such an extent that the active material of the negative plates has turned brown, both positive and negative groups may have to be replaced.
Repairing Lead Parts
The portable carbon burning outfit used for battery repairs is operated from the battery itself, making it possible to make repairs at the user's residence without using a gas flame.
This outfit can be secured from the Delco-Light Company, Dayton, Ohio, and consists of a carbon holder with cable, clamp, and one-fourth inch carbon rods. Six cells are usually required to properly heat the carbon. If it is completely discharged an outside source must be used. For this purpose a six-volt automobile battery is suitable, or a tray of demonstrating batteries, one terminal being connected to the connection to be burned, the other to the cable of the burning tool. A little experience will soon demonstrate the number of cells necessary to give a satisfactory heat. The cable is connected by means of the clamp to a cell in the battery, the required number of cells away from the joint to be burned. Care should be taken that contact is made by the clamp, the lead being scraped clean before the connection is made. The carbon should be sharpened to a long point like a lead pencil and should project not more than 2 inches from the holder. (Fig. 317.)
After being used a short time, the carbon will not heat properly, due to a film of scale formed on the surface. This should be cleaned off with a file.