ally, no buckling will occur. Unequal expansion,
however, causes buckling.

1. Over discharge. If discharge is carried too far, the expansion of
the active material on account of the formation of lead sulphate will
bend the grids out of shape, and may even break them.

2. Continued Operation with Battery in a Discharged Condition. When a
considerable amount of lead sulphate has, formed, and current is still
drawn from the battery, those portions of the plate which have the
least amount of sulphate will carry most of the current, and will
therefore become heated and expand. The parts covered with sulphate
will not expand, and the result is that the parts that do expand will
twist the plate out of shape. A normal rate of discharge may be
sufficient to cause buckling in a sulphated plate.

3. Charging at High Rates. If the charging rate is excessive, the
temperature will rise so high that excessive expansion will take
place. This is usually unequal in the different parts of the plate,
and buckling results. With a battery that has been over discharged,
the charging current will be carried by those parts of the plates
which are the least sulphated. These parts will therefore expand while
others will not, and buckling results.

4. Non-Uniform Distribution of Current Over the Plates. Buckling may
occur in a battery which has not been over-discharged, if the current
carried by the various parts of the plate is not uniform on account of
faulty design, or careless application of the paste. This is a fault
of the manufacturers, and not the operating conditions.

5. Defective Grid Alloy. If the metals of which the grids are composed
are not uniformly mixed throughout the plate, areas of pure lead may
be left here and there, with air holes at various points. The
electrolyte enters the air holes, attacks the lead and converts the
grid partly into active material. This causes expansion and consequent
distortion and buckling.

Buckling will not necessarily cause trouble, and batteries with
buckled plates may operate satisfactorily for a long time. If,
however, the expansion and twisting has caused much of the active
material to break away from the grid, or has loosened the active
material from the grids, much of the battery capacity is lost. Another
danger is that the lower edges of a plate may press against the
separator with sufficient force to cut through it, touch the next
plate, and cause a short-circuit.

Shedding, or