Porsche 928 Workshop Manual page 472

27
Starter,
power supply 928
3. Measure specific gravity of each cell.
Specific Gravity
appron. 1.28
approx. 1.20
Battery Condition
Fully charged
Half charged
Remarks
Recharge. if
1. car ist not used for
a long time.
2. temperatures are be-
low + IO0 C/50' F or
3. specific gravity will
not rise in spite of dri-
ving long distances
(check alternator.
regulator, belts).
appron. 1.10 Weak
Recharge immediately
4. Checking the specific gravity will not only
supply information on charge condition of
battery. but also any possible defects,
a - Specific Gravity of one cell much lower
than that of other cells: short circuit in
weak cell, battery defective.
b - Specific Gravity of two neighboring cells
much lower than that of other cells: leak
between both weak cells. battery defective.
c - Specific Gravity correct in all cells. but
battery voltage drops excessively under load:
poor soldered connection between cells,
battery defective,
5. If necessary. add distilled water to correct
level.
27 - 2
Checking Battery
Printed in Germany