discharge the battery beyond the
safe limits. Batteries discharging at low rates are liable to be
overdischarged before the voltage gives any indication of the
discharged condition. This is another reason why hydrometer readings
should be used as a guide.

A battery must be charged as soon as it becomes discharged. It is, in
fact, a good plan, and one which will lengthen the life of the
battery, to charge a battery when it is only about three fourths
discharged, as indicated by the hydrometer. Suppose, for instance,
that the specific gravity of the fully charged battery is 1.250, and
the specific gravity when the battery is discharged is 1.180. This
battery has a range of 1.250 minus 1.180, or 70 points between charge
and discharge. This battery will give a longer life if its discharge
is stopped and the battery is put on charge when the gravity falls to
1.200, a drop of 50 points instead of the allowable 70.

Allowing discharged battery to stand without charge. A battery should
never be allowed to stand more than one day in a discharged condition.
The battery will continue to discharge although no current is drawn
from it, just as an automobile battery will. See page 89. The battery
plates and separators will gradually become badly sulphated and it
will be a difficult matter to charge the battery up to full capacity.

Battery Troubles

Farm lighting batteries are subject to the same general troubles that
automobile batteries are, although they are not as likely to occur
because the operating conditions are not as severe as is the case on
the automobile. Being in plain view at all times, and not being
charged and discharged irregularly, the farm lighting battery is not
likely to give as much trouble as an automobile battery. Neglect, such
as failure to keep the electrolyte up to the proper height, failure to
charge as soon as the battery becomes discharged, overdischarging,
allowing battery to become too hot or too cold, allowing impurities to
get into the cells, will lead to the same troubles that the same
treatment will cause in an automobile battery, and the descriptions
of, and instructions for troubles in automobile batteries will apply
in general to farm lighting batteries also.

When a battery has been giving trouble, and you are called: upon to
diagnose and remedy that trouble, you should:

1. Get all the details as to the length of time the battery has been
in service.

2. Find out what regular at