Page 66 - Vauxhall 20-60 H.P. (R Type) Chassis Shop Manual

VAUXHALL 20-60 SHOP MANUAL

GROUP VIII

ELECTRICAL SYSTEM

BATTERY

ADDING WATER TO BATTERY

SECTION The electrolyte in the battery must cover the plates, and should be just
350 below the bottom of the vent plugs. Distilled water should be added once
weekly to keep the level up to this point. Do not add acid except as directed
in ( Section 351 ). It is essential that water used to fill up the battery is
distilled, as tap water contains metals in solution which will ultimately give
rise to troubles.

Never keep distilled water in a metal container of any description.

SPECIFIC GRAVITY OF ELECTROLYTE

SECTION As the battery is charged and discharged the electrolyte reacts chemically
351 with the plates of the battery, the specific gravity of the electrolyte

changing as the reaction proceeds. The state of charge of the battery is
thus indicated by the specific gravity of the electrolyte. As the battery is
.
charged, the specific gravity of the electrolyte increases, reaching 1 285 t0
.
1 300 when the battery is fully charged and as the battery is discharged the
.
specific gravity of the electrolyte decreases, reaching approximately 1 150
when the battery is fully discharged.

The specific gravity of the acid should be tested by means of a Lucas Syphon
Hydrometer, see that the electrolyte in the battery is at its correct level.
Readings should be taken after a run on the car, when the electrolyte will be
thoroughly mixed.

To assemble the hydrometer insert the float, thin end first, into the barrel,
then wet the plug carrying the rubber tube and push it into position and the
instrument is ready for use. Holding the instrument vertically compress the
bulb and insert the red rubber tube as far as possible into the electrolyte, then
gradually release the pressure on the bulb until the electrolyte rises in the
1
barrel to lift the hydrometer float about 1 / 2 ”. Removing the hydrometer from
the cell, note the scale reading at the surface of the electrolyte, and this gives
the specific gravity. Care must be taken that the stem of the float does not
touch any point of the barrel or bulb while the reading is being taken.

REPLACING ACID

SECTION Acid should only be added if some has been spilled or leaked from the cells.
352 The best brimstone sulphuric acid must be used, diluted with distilled water
.
.
to a specific gravity of 1 225/1 285 at 6o° F. The proportion is one part of
acid to four parts of water by volume.

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