Open−Circuit Voltage Measurement - Porsche 996 TT Repair Manual

Battery charging condition in
tropical climatic zone (hot
countries)
discharged
half charged
well charged
The gravity of electrolyte must be at least 1.24 kg/dm³.
If the gravity of electrolyte is too low, charge battery.
After charging the battery, repeat the electrolyte gravity
test.
The measuring values for the gravity of electrolyte of the individual battery cells should not deviate by more
than 0.03 kg/dm ³ from eachother.
Examples of non−permissible specific gravity of electrolyte deviations:
Battery cell: 1
Gravity of electrolyte per cell in kg/dm³
Example 1: 1.24
Example 2: 1.26
Example 1: The gravity of electrolyte in cell 4 is too low.
Example 2: The gravity of electrolyte in cells 4 and 5 is too low. The specific gravity of electrolyte deviations
between the battery cells is larger than 0.03 kg/dm³.
If the nominal values are not achieved, replace battery.
If the nominal values are achieved, screw in the original plug again.
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Open−circuit voltage measurement
Note
• Use a hand−held multimeter to measure the battery voltage. Gr. 2.5; Workshop Equipment Manual
1. Switch ignition off and remove ignition key.
2. Disconnect ground strap on the battery.
Note
• After charging and a waiting time of at least 2 hours during which the battery should neither be loaded
or charged.
3. Measure the battery voltage with a hand−held
multimeter.
The battery open−circuit voltage should not fall below 12.5V.
If the hand−held multimeter shows 12.5V or over, the battery voltage is
OK.
Checking gravity of electrolyte
einordnung
Spec. gravity
in kg/dm³
1.08
1.16
1.23
2 3
1.25 1.25
1.26 1.25
4 5
1.10 1.24
1.14 1.18
6
1.25
1.24
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