Porshe 911 (997). Manual - part 1191

again with plenty of water. If acid has been drunk unintentionally, consult a doctor immediately.
-5-

 Observe information on the battery, in the Technical Manual and in the Driver's Manual.

-6-

 Danger of explosion:

A highly explosive detonating gas mixture is formed when charging batteries.

• 

-7-

 Disposal:

Hand in old batteries at a collection point.

• 

-8-

 Never dispose of old batteries in the domestic rubbish.

Battery handling requirements

Low-maintenance battery

–  Battery terminals do not need to be greased.

–  The battery terminal clamps should only be attached manually, without excessive force, to prevent

damage to the battery housing.

–  The tightening torque for the battery terminals is 5 Nm (3.5 ftlb.).

–  If the battery is to be reconnected, proceed according to →   Work instructions after disconnecting

the battery.

–  To ensure that the battery does not leak, it is essential to ensure that the original plugs supplied with

the battery are screwed into the battery openings.

–  In the event of loss or damage, only original plugs of the same design should be used.

–  The plugs must be fitted with an O-ring

seal.

Battery central venting

Note

State of the art batteries are fitted with central venting -A- .

• 

The gas generated during charging emerges centrally through an opening on the upper cover side.
The backfire protection is integrated at the same position, which prevents the ignition of the
combustible gas present in the battery.

• 

Diagnostic system: reading out fault memory and activating systems

Battery handling requirements

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Central venting

In batteries with hose/pipe -A- for the central venting, ensure that the hose is not pinched. Only then
can the battery be freely vented.

• 

Visual inspection of battery

Before measurements such as open-circuit voltage, gravity of electrolyte or the battery load test are carried
out, a visual inspection of the battery must be performed.
Through this check, it can be determined:

Whether the housing of the battery is damaged. Acid can leak out due to damage of the housing.

• 

Whether the battery terminals (battery line connections) are damaged. Contact of the line connections
cannot be guaranteed if the battery terminals are damaged. This can cause a line fire and malfunctions
in the electrical system.

• 

Checking acid level of low-maintenance battery

Note

Use a commercially available battery filling bottle.

• 

The correct acid level of the battery is an important factor for long and efficient operation of the
battery.

• 

When the acid level is too low, a capacity loss (performance loss) of the battery occurs, which is
caused by the cell plates drying out. If the cell plates are not surrounded by electrolyte (battery acid),
this will lead to corrosion of the lead plates, the plate bridges and the cell connectors. The result of
the corrosion is that battery functioning cannot be guaranteed. The battery will become
unserviceable.

• 

If the acid level is too high, damage can occur by the battery acid (sulphuric acid/water mixture)
leaking out of the battery.

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Diagnostic system: reading out fault memory and activating systems

Battery central venting

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1. Switch off ignition and remove ignition key.

Removing battery cover

2. Remove battery cover.

Emerging battery acid. Observe → 270601 Checking battery - General warning notes.

3. Unscrew battery plugs.

4. Shine a torch into the battery. The acid level of the battery must be at the protruding lug.

–  If the acid level is too low, refill with distilled water using the battery filling bottle.

5. Screw in battery plugs again and ensure that they are seated correctly.

6. Remount battery cover.

Checking gravity of electrolyte

Note

Only for low-maintenance batteries.

• 

Note

Use commercially available battery acid tester.

• 

The acid density test provides information about the state of the battery in conjunction with the
battery load test.

• 

The temperature of the battery acid must be at least 10°C .

• 

The gravity of electrolyte must be checked as follows in all battery cells (low-maintenance battery) :

1. Switch off ignition and remove ignition key.

Emerging battery acid. Observe → 270601 Checking battery - General warning notes.

2. Unscrew all battery plugs (plugs of the battery cells).

3. Dip the acid siphon or the pipette into the battery cell and take up the battery

acid.

4. Read off the gravity of electrolyte in kg/dm³ on the scale of the battery acid tester and compare with

the following table.

Diagnostic system: reading out fault memory and activating systems

Checking acid level of low-maintenance battery

4923

Battery charge state in normal climatic zones

Spec. gravity in kg/dm³

discharged

1.12

half charged

1.20

well charged

1.28

Battery charge state in tropical climatic zones (hot countries)

Spec. gravity in kg/dm³

discharged

1.08

half charged

1.16

well charged

1.23

The gravity of electrolyte must be at least 1.24 kg/dm³ in normal climatic zones.

–  If the gravity of electrolyte is too low, charge

battery.

–  After charging the battery, repeat the electrolyte gravity

test.

The measured values for the gravity of electrolyte of the individual battery cells should not deviate by more
than 0.03 kg/dm³ from each other.

Examples of non-permissible specific gravity of electrolyte deviations:

Battery cell:

1

2

3

4

5

6

Gravity of electrolyte per cell in kg/dm³

Example 1:

1.24

1.25

1.25

1.10

1.24

1.25

Example 2:

1.26

1.26

1.25

1.14

1.18

1.24

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 greater than 0.03 kg/dm³.

–  If the nominal values are not achieved, replace battery.

–  If the nominal values are achieved, screw in the original plugs

again.

Open-circuit voltage measurement

Note

Use a hand-held multimeter to measure the battery voltage.

• 

Diagnostic system: reading out fault memory and activating systems

Checking gravity of electrolyte

4924