whenever
the car is running at more than about 10 miles per hour, regardless of
what their condition may be.

In farm lighting outfits, the charging is under the control of the
operator, and the battery is charged when a charge is necessary. There
is, therefore, very much less danger of starving or overcharging the
battery. The operator must, however, watch his battery carefully, and
charge it as often as may be necessary, and not allow it to go without
its regular charge.

The generator of a farm lighting outfit is usually driven by an
internal combustion engine furnished with the outfit. The engine may
be connected to the generator by a belt, or its shaft may be connected
directly to the generator shaft. A switchboard carrying the necessary
instruments and switches also goes with the outfit. The charging of
farm lighting batteries is very much like the charging of automobile
batteries on the charging bench, except that the batteries are at all
times connected to switches, by means of which they may be put on the
charging line.

Some plants are so arranged that the battery and generator do not
provide current for the lights at the same time, lights being out
while the battery is charging. In others the generator and battery, in
emergency, may both provide current. In others the lights may burn
while the battery is being charged; in this case the battery is
sometimes provided with counter-electromotive force cells which permit
high enough voltage across the battery to charge it and yet limit the
voltage across the lamps to prevent burning them out or shortening
their life. In some cases the battery is divided into two sets which
are charged in parallel and discharged in series.

Relation of the Automobile Storage Battery Man to the Farm Lighting
Plant. Owners and prospective owners of farm lighting plants generally
know but little about the care or repair of electrical apparatus,
especially batteries, which are not as easily understood as lamps,
motors or generators. Prospective owners may quite likely call upon
the automobile battery repair man for advice as to the installation,
operation, maintenance, and repair of his battery and the automobile
battery repairman should have little trouble in learning how to take
care of farm lighting batteries. The details in which these batteries
differ from starting batteries should be studied and mastered, and a
new source of business will be opened.

Farm lighting plants