ed
internally. The separator troubles described on page 81 eventually
lead to short-circuited cells.

2. Foreign Material. If a piece of lead falls between plates so as to
later punch a hole through a separator, a short circuit will result.
Great care should be taken in burning plates on the straps to prevent
lead from running down between plates, as this lead will cause a short
circuit by punching through the separator.

3. Accumulation of Sediment. The active material which drops from the
plates accumulates in the "mud" space in the bottom of the jar. If
this rises until it touches the bottom of the plates, a short-circuit
results. Usually it is advisable to renew the positives in a battery
which has become short-circuited by sediment, since the sediment comes
largely from the positives, and if they have lost enough active
material to completely fill the sediment space, they are no longer fit
for use.

4. Badly sulphated plates and separators, impurities which attack the
plates.

Loss of Capacity

A battery loses capacity due to a number of causes. Some of them have
already been considered.

1. Impurities in the Electrolyte. These have already been discussed.

2. Sulphation. This also has been described.

3. Loose Active Material, as already described. The active materials
which are not in contact with the grids cannot do their work.

4. Incorrect Proportions of Acid and Water in the Electrolyte. In
order that all the active material in the plates may be utilized,
there must be enough acid in the electrolyte, and also enough water.
If there is not enough acid, the battery will lack capacity. If there
is too much acid, the acid when the battery is fully charged will be
strong enough to attack and seriously damage the plates and
separators. Insufficient amount of acid may be due to replacing, with
water, electrolyte which has been spilled or which has leaked out. Too
much acid results from an incorrect proportion of acid and water in
the electrolyte, or from adding acid instead of water to bring the
electrolyte above the plate tops, and causes sulphation, corroded
plates, and carbonized separators.

The remedy for incorrect proportions of acid and water in the
electrolyte is to give the battery a full charge and adjust the
gravity by drawing off some of the electrolyte and replacing it with
water, or 1.400 specific gravity electrolyte, as the case may require.

5. Separators Clogged. The pores of the