1928 Cadillac - GM Heritage Center

84 CADILLAC OPERATOR'S MANUAL
GENERAL
INFORMATION
85
be moved by prying it. Do not pry against the brush itself, and be very
careful not to spring the brush holder.
Do not under any circumstances put oil on the commutator of the generator.
Storage Battery
The storage battery is a three-cell, six-volt Exide battery made especially
for the Cadillac electrical system by the Electric Storage Battery Company
of Philadelphia, Pennsylvania. The battery compartment is between the
right-hand running board and the frame. The door of the compartment
operates the same as the door of the tool compartment, described on page 31.
Distilled or other approved water should be added to bring the level up to
the bottom of the filling tubes.
Each cell is provided with a filling tube and vent plug. To remove a
vent plug, turn it as far as possible counter-clockwise and then lift it straight
up. To install it, set the plug in place and turn it clockwise until tight. If
a plug is lost or broken, obtain a new one and install it as soon as possible.
Nothing but pure distilled or other approved water should be added to
the battery solution. Melted artificial ice or rain water caught in an earthenware
receptacle may be used. Hydrant water or water that has been in
contact with metallic surfaces will cause trouble if used. Acid must never be
added to the battery.
After adding water to the storage battery in freezing weather, the car
should immediately be run far enough to mix the water and acid solution
thoroughly. If the car is parked immediately after adding water, the water
is likely to stay on top of the acid solution and may freeze, causing extensive
damage.
If one cell regularly requires more water than the others, a leaky jar is
indicated. A leaky jar should be replaced immediately by a new one, as
even a very slow leak will in time result in the loss of all the solution in the
cell.
Specific Gravity of Battery Solution
As the storage battery is charged and discharged, the solution reacts
chemically with the plates of the battery, the specific gravity of the solution
changing as the reaction proceeds. The state of charge of the battery
is thus indicated by the specific gravity of the solution. As the battery is
charged, the specific gravity of the solution increases, reaching 1.270 to
1.285 when the battery is fully charged. The specific gravity of the solution
decreases as the battery is discharged. A fully discharged battery has a
specific gravity of 1.150 to 1.165-
Figure 40. The storage battery is located in the right-hand dust shield.
Adding Water to Storage Battery
The battery is filled with a solution from which the water slowly evaporates,
and fresh distilled or other approved water must be added at intervals
to maintain the correct level. The level should be inspected at least every
1000 miles, and in warm weather every 500 miles or at least every two weeks.
A hydrometer is the instrument used to measure the specific gravity of a
solution. A hydrometer syringe is a hydrometer especially designed for
convenience in testing the specific gravity of the acid solution in the storage
battery. A hydrometer syringe can be obtained at any battery service station.
Be sure and get a reliable instrument, for cheap ones may be in error
as much as 25 or 30 points.
The specific gravity of the acid solution should never be tested immediately
after adding distilled water. If the solution is below the plates so that