Fig. 218. Tapping Connectors in Place.
Preparatory to Charging After Battery
Has Been Opened and Shorts Removed
The next operation is to put the battery on charge. Grasp each post in the jaws of a pair of gas pliers and work the pliers back and forth, Fig. 217, so as to remove the scale and allow the connecting straps to make good contact. Now take a knife and cut off the rough edges left in the connecting straps by the drill. Taper the edge, if necessary to go on post. Turn the connectors upside down and pound gently in position, Fig. 218, to make a good connection. Temporary charging connections may also be made by burning lead strips on the posts. This being properly done, the battery is ready for charging. Check up the connections to be sure they are correct.
Now put the battery on charge, and charge at a low rate. Do not allow the temperature of any cell to rise above 110°F. Continue the charge until the electrolyte clears up, and its specific gravity stops rising and the plates have a normal color over their entire surface. Fully charged positive plates have a chocolate brown color, and fully charged negative plates have a dark gray color. By holding an electric light directly over a cell, and looking down, the color of both negatives and positives may be determined. Do not take the battery off charge until you have obtained these results, although it may be necessary to continue the charge for two, three, four, or five days. In this preliminary charge it is not necessary to bring the gravity up to 1.280, because the electrolyte is not to be used again, and the plates will become charged completely, regardless of what the gravity is. The essential thing is to charge until the electrolyte becomes perfectly clear, the gravity stops rising, and the plates have the right color. The Cadmium test may be used here to determine when the plates are charged. If the gravity rises above 1.280 during the preliminary charge, adjust it to 1.280 by drawing out some of the electrolyte and adding distilled water. The battery must stay on charge until you have the desired conditions. If one cell does not charge,--that is, if its specific gravity does not rise,--you have probably not freed all the shorts, and must take the element out of the jar again and carefully inspect it for more shorts.
Right here is where one of the most important questions may be asked about rebuilding batteries. Why must you free the shorts and put the battery on charge? Why not save time by putting in all new separators, sealing the battery, burning on the cell connectors, and then putting it on charge? If you have ever treated a battery in this way, what results did you get? Why did you have a badly unbalanced gravity of electrolyte? How could you know what specific gravity electrolyte to put in each cell? Perhaps one was charged, one only half charged, and the other dead. Suppose the dead cell had impurities in it. How could you get rid of them? Suppose the battery showed poor capacity on test, what would you do?
Washing and Pressing the Negatives
To continue the actual work on the battery. The battery being fully charged,—the electrolyte clear, the plates of normal color, the specific gravity no longer rising,— remove it from the charging bench and put it on the work bench. Draw each element and let drain as in Fig. 197.
Here again the labeled boxes described on page 183 come in handy. Separate one group, remove the separators, and put one group in each end of box to keep clean. Separate another group, And nest the plates, Fig. 219, the negative with the negative, and positive with positive. Separate the third element and put groups in the boxes. Pour the old electrolyte out of the jars, and wash out the jars as described on page 360. You now have the plates in the best possible shape for handling. Take the boxes containing the plates to the sink. Have the plate press and the plate press boards ready for use.
If, for any reason, you are called away from your work at this point to be gone for five minutes, do not leave the fully charged negatives exposed to the air, as they will become very hot. Cover them with water. A one-gallon stone or earthenware jar will hold the negative plates of a 100 ampere hour battery if you nest two of the groups. You may also put negatives back in jars from which they were taken, and fill with water.