This test may be made by using a voltmeter instead of lamps, as shown in Fig. 221. If a voltmeter is used, be especially careful to have the part projecting above the liquid perfectly dry. A leaky cell will be indicated by a reading on the meter equal to the line voltage.
A third method uses a Ford ignition coil, as shown in Fig. 222. A leak will be indicated by a spark, or by the vibrator making more noise than it ordinarily does. Instead of using the Ford coil, as shown in Fig. 222, the test may be made as shown in Fig. 223. Fill the jar to within an inch of the top with electrolyte and immerse one of the high tension wires in the electrolyte. Attach the other high tension wire to a wire brush, comb, or rod having a wooden handle and rub it over the outside of the jar. A leak is shown by a spark jumping to the jar.
The test may also be made without removing the jar. If the lead lined box be made two feet long, the entire battery may be set in the box so that the electrolyte in the box comes within an inch of the top of the battery case. Fill each jar with weak electrolyte and make the test as before. If this is done, however, remove the battery immediately after making the test and wipe the case dry with a cloth. To make the test in this way the case must be considerably acid eaten in order to have a circuit through it to the jar.
Removing Defective Jars
The method of removing the jars from the case depends on the battery. In some batteries the jars are set in sealing compound. To remove a jar from such a battery, put the steam hose from your steamer outfit into the jar, cover up the top of the jar with rags, and steam the jar for about five minutes. Another way is to fill the jar with boiling hot water and let it stand for fully five minutes. Either of these methods will soften the sealing compound around the jar so that the jar may be pulled out. To remove the jar, grasp two sides of the jar with two pairs of long, flat nosed pliers and pull straight up with an even, steady pull. Have the new jar at hand and push it into the place of the old one as soon as the latter is removed. The new jar should first be steamed to soften it somewhat. Press down steadily on the new jar until its top is flush with the tops of the other jars.
Some batteries do not use sealing compound around the jars, but simply use thin wooden wedges to hold the jars in place, or have bolts running through opposite faces of the case by means of which the sides are pressed against the jars to hold them in place. The jars of such batteries may be removed without heating, by removing the wedges or loosening the bolts, as the case may be, and lifting out the jars with pliers, as before. New jars should be steamed for several minutes before being put in the case. When you put jars into such batteries, do not apply too much pressure to them, as they may be cracked by the pressure, or the jar may be squeezed out of shape, and the assembling process made difficult.
Repairing the Case
