Charging Outside Negative Plates
Individual negative plates are always received dry, which makes it necessary to charge them before using. The best way to charge such plates is as follows: Set up 7 loose negative plates in a KXG-13 jar together with a good positive group, using KXG separators to prevent the plates touching. Then stretch a piece of wire solder across the lugs at the top of the negative plates and solder the wire to the plates. Fig. 316. The jar may then be filled with 1200 specific gravity and the plates charged at a 12-ampere rate until maximum gravity is obtained. Never use negative plates unless they have been treated as described above. After the charge is completed, the negative plates may be placed in distilled water and kept until ready for use. Always be sure to give a charge to maximum gravity after burning on new negative plates to an element.
Pressing Negative Plates
After badly sulphated cells are recharged, it is sometimes advisable to remove the elements and, press the negative plates, as explained on page 351. Care should be taken to prevent the negative plates from drying out while making repairs, in order to avoid the long charge necessary for dried negative plates.
The battery should be charged to maximum gravity before attempting to press the plates.
It is not necessary and will do no good to press the positive plates.
In some cases the active material may be nearly all out of the outside negative plates and the inside negatives may be in good condition, in which case new charged plates should be burned on. (Fig. 322.)
Salvaging Replaced Cells
When it has been necessary to replace cells which have been in service, the elements can very often be saved and assembled again and used as replacement cells in batteries which are several years old. In no case should the cells be used as new cells.