atteries. There are two sizes, large and
small, see page 389.

68. Style "B" peening press for sealing posts of Prest-O-Lite
batteries to covers, see page 390.

69. Pressure tongs for forcing lead collar oil posts of Vesta
batteries, see page 415.

70. Special wrench for tightening sealing nut oil Titan batteries.

71. Special reamer for cutting sealing ring oil Universal batteries.

The list of special tools is not intended to be complete, and the
repairman will probably find other special tools necessary from time
to time. In any case, it is best to buy from the battery manufacturer
such special tools as are necessary for the batteries that come in for
repairs. It is sometimes possible to get along without the special
tools, but time and labor will be saved by using them.

DESCRIPTIONS OF TOOLS AND EQUIPMENT NAMED IN FOREGOING LIST

Charging Equipment

A battery is charged by sending a direct current through it, this
"charging" current entering the battery at, the positive terminal and
passing out at the negative terminal. To send this current through the
battery, a voltage of about 7.5 volts is applied to each battery.

Two things are therefore necessary in charging a battery:

1. We must have a source of direct current.
2. The voltage impressed across each battery must be, about 2.5 per
cell. The charging voltage across each six volt battery must
therefore be 7.5, and for each twelve volt battery the charging
voltage must be about 15 volts.

With the battery on the car, there are two general methods of
charging, i. e., constant potential (voltage) and constant current.
Generators having a constant voltage regulator have a constant voltage
of about 7.5, the charging current depending upon the condition of the
battery. A discharged battery thus receives a high charging current,
this current gradually decreasing, or "tapering" as the battery
becomes more fully charged. This system has the desirable
characteristic that a discharged battery receives a heavy charging
current, and a fully charged battery receives a small charging
current. The time of charging is thereby decreased.

With a constant-current charging system, the generator current output
is maintained at a certain value, regardless of the state of charge of
the battery. The disadvantage of this system is that a fully charged
battery is charged at as high a rate and in most cases at a higher
rate than a discharged battery.

In th