battery rack clean. After a charge
is completed, wipe off any electrolyte that may be running down the
outsides of the jars. Wipe all electrolyte and other moisture from the
battery rack. Occasionally go over the rack with a rag wet with
ammonia or washing soda solution. Then finish with a dry cloth. Paint
the rack with asphaltum paint once a year, or oftener if the paint is
rubbed or scratched.

If sand trays are used, renew the sand whenever it becomes very wet
with electrolyte. Keep the terminals and connectors clean. Near the
end of a charge, feel each joint between cells for a poor connection.
Watch also for corrosion on the connections. Corrosion is caused by
the electrolyte attacking any exposed metals other than lead, near the
battery, resulting in a grayish deposit on the connectors or bolts at
the joints. Such joints will become hotter than other joints, and may
thus be located by feeling the joints after the battery has been
charged for some time. Corrosion may be removed by washing the part in
a solution of baking soda.

Be very careful to keep out of the cells anything that does not belong
there. Impurities injure a cell and may even ruin it. Do not let
anything, especially metals, fall into a cell. If this is done
accidentally, pour out the electrolyte immediately, put in new
separators, wash the plates in water, fill with electrolyte having a
gravity about 30 points higher than that which was poured out, and
charge. The cell may be connected in its proper place and the entire
battery charged. Vent plugs should be kept in place at all times,
except when water is added to the electrolyte.

Keep the Electrolyte Above the Tops of the Plates. If the battery has
glass jars, the height of the electrolyte can be seen easily. If the
battery has sealed rubber jars, the height of the electrolyte may be
determined with a glass tube, as described on page 55. In most
batteries the electrolyte should stand from three-fourths of an inch
to an inch above the plates. Some jars have a line or mark showing the
proper height of the electrolyte. A good time to inspect the height of
the electrolyte is just before putting the battery on charge. If the
electrolyte is low, distilled water should be added to bring it up to
the proper level. Water should never be added at any other time, as
the charging current is required to mix the water thoroughly with the
electrolyte.

Determining the Condition of the Cells. The specific gr