of possible different designs in general use today.

The design and dimensions of batteries vary considerably, but the
general constructions are similar. The special processes of the
manufacturers are of no special interest to the repairman, and only a
general description will be given here.

A starting and lighting battery consists of the following principal
parts:

1. Plates
2. Separators
3. Electrolyte
4. Jars
5. Covers
6. Cell Connectors and Terminals
7. Case Plates

Of the two general types of battery plates, Faure and Plante, the
Faure, or pasted type, is universally used on automobiles. In the
manufacture of pasted plates there are several steps which we shall
describe in the order in which they are carried out.

Casting the Grid. The grid is the skeleton of the plate. It performs
the double function of supporting the mechanically weak active
material and of conducting the current. It is made of a lead antimony
alloy which is melted and poured into a mould. Pure lead is too soft
and too easily attacked by the electrolyte, and antimony is added to
give stiffness, and resistance to the action of the electrolyte in the
cell. The amount of antimony used varies in different makes but
probably averages 8 to 10%.

The casting process requires considerable skill, the proper
composition of the metal and the temperature of both metal and moulds
being of great importance in securing perfect grids, which are free
from blowholes, and which have a uniform structure and composition.
Some manufacturers cast two grids simultaneously in each mould, the
two plates being joined to each other along the bottom edge.

Trimming the Grids. When the castings have cooled, they are removed
from the moulds and passed to a press or trimming machine which trims
off the casting gate and the rough edges. The grids are given a rigid
inspection, those having shrunken or missing ribs or other defects
being rejected. The grids are now ready for pasting.

[Fig 4. Grid, Trimmed, and Ready for Pasting]

Fig. 4 shows a grid ready for pasting. The heavy lug at one upper
corner is the conducting lug, for carrying the current to the strap,
Fig. 5, into which the lugs are burned when the battery is assembled.
The straps are provided with posts, to which the intercell connectors
and terminal connectors are attached. The vertical ribs of the grids
extend through the plate, providing mechanical strength and
conductivity, while the small horiz