same time overheats the battery
and causes excessive gassing. The excessive current may also overheat
the generator, while a normal or insufficient charging current will
not injure the generator.

It is possible, but not probable, that the generator may be sending
current through the battery in the wrong direction, so as to discharge
it instead of charging it. This will happen if a very badly discharged
battery is installed with the connections reversed. If a fully or even
partly charged battery is installed with its connections reversed, the
battery will generally reverse the polarity of the generator
automatically, and the battery will be charged in the proper
direction, although the current flow in the charging circuit is
actually reversed.

Engine Running, Lamps On. Under these conditions, the generator should
supply the current for the lights, and still send a charging current
of 3 to 5 amperes through the battery. This means that the current
drawn from the battery when the engine is not running and the lights
are all turned on should be at least several amperes less than the
charging current which the generator sends into the battery when the
engine is running and the lamps are turned off.

Tests to Be Made by the Repairman

The battery repairman can, and always should, make a few simple tests
which will tell him whether the various conditions of operation are
normal. This should be done as follows:

1. Install the battery carefully (see page 236), and connect the
negative battery cable to the negative battery terminal. Now tap the
positive battery cable on the positive battery terminal. If a snappy
spark is obtained when this is done, some of the switches are open or
are defective, the cutout is stuck in the closed position, or there
are grounds or short-circuits in the parts which are permanently
connected to the battery.

Even though no spark is obtained when you tap the positive battery
cable on the positive battery terminal, there may be some trouble
which draws enough current from the battery to cause it to run down in
a short time. To detect such trouble, connect a voltmeter (which has
sufficient range to indicate the battery voltage) between the positive
battery cable and the positive battery terminal. (Cable is
disconnected from the terminal.) If the voltmeter now gives a reading
equal to the voltage of the battery, there is some condition causing a
current leakage from the battery, such as a