ants differ considerably from the
starting batteries used on automobiles. The starting battery is called
upon to deliver very heavy currents for short intervals. On the car
the battery is always being charged when the car is running at a
moderate speed or over. The battery must fit in the limited space
provided for it on the car, and must not lose any electrolyte as the
car jolts along over the road. It is subjected to both high and low
temperatures; and is generally on a car whose owner often does not
know that his car has such a thing as a battery until his starting
motor some day fails to turn over the engine. All starting batteries
have wooden cases (some now use rubber cases), hard rubber jars, and
sealed on covers. The case contains all the cells of the battery.
Automobile batteries have, therefore, become highly standardized, and
to the uninformed, one make looks just like any other.

Farm lighting batteries, on the other hand, are not limited as to
space they occupy, are not subjected to irregular charging and
discharging, do not need leak proof covers, and are not called upon to
delivery very heavy currents for short periods. These facts are taken
advantage of by the manufacturers, who have designed their farm
lighting batteries to give a much longer life than is possible in the
automobile battery. As a result the farm lighting battery differs from
the automobile battery in a number of respects.

Jars. Both glass and rubber are used for farm lighting battery jars,
and they may or may not have sealed-in covers. Fig. 294 shows a glass
jar of an Exide battery having a hard rubber cover, and Fig. 295 shows
a Prest-O-Lite glass jar cell having a cover made of lead and
antimony. Unsealed glass jars, such as the Exide type shown in Fig.
324, generally have a plate of glass placed across the top to catch
acid spray when the cell is gassing. Each jar with its plates and
electrolyte forms a complete and separate unit which may easily be
disconnected from the other cells of the battery by removing the bolts
which join them. In working on a farm lighting battery, the repairman,
therefore, works with individual cells instead of the battery as a
whole, as is done with automobile batteries.

[Fig. 294 Exide "Delco Light" farming lighting cell with
hard rubber cover]

Batteries with sealed jars are generally shipped completely assembled
and filled with electrolyte, and need only a freshening charge before
being put i