AUDI A4 1996 B5 / 1.G Battery User Guide

27-10

Electrolyte level too high

Special tools, test equipment and auxiliary
items

Commercially available hydrometer
Note:
If the electrolyte level is too high, the sulfuric acid/water mixture will leak
to the outside of the battery and damage functional components in the
engine compartment.
- If electrolyte level is too high (overfilling), i.e., it is above internal
electrolyte level mark (lip of plastic flange) or external maximum line,
draw off excess electrolyte using commercially available hydrometer.
- Draw off electrolyte using hydrometer until electrolyte level has
reached lip of plastic flange or maximum line.
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27-11

Batteries with central gas vent

CAUTION!

Make absolutely certain that only batteries of
the most recent design with central gas
vents are installed.
Always use the original cell caps. The caps
must be equipped with an O-ring seal.
There are two types of batteries with central gas
vents:
Batteries with a hose on the central gas vent
Batteries without a hose on the central gas
vent
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27-12

No-load voltage, checking


CAUTION!

Battery cell caps must be screwed in tightly
when charging, measuring voltage or
performing load tests.
Always comply with the following
instructions otherwise a correct
measurement cannot be assured.

Special tools, test equipment and auxiliary
items
VAG1715 multimeter or
VAG1362 minitester or
Multimeter (Fluke 83 or equivalent)

Notes:
When testing the no-load voltage of a battery
installed in a vehicle, make sure the battery
Ground (GND) strap is disconnected.
The battery must not have been under a load
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for at least two hours before the test.
The battery must not have been charged at
least two hours before the test.
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27-13
Use the following procedure for testing the
voltage of a battery which is not under load:

- Switch ignition off.

- Disconnect battery Ground strap.

- Measure voltage between battery terminals.


12.5 volts or higher: battery OK

Below 12.5 volts: recharge battery
immediately Page 27
-21

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27-14

Specific gravity, checking


Special tools, test equipment and auxiliary
items

CAUTION!
Notes:
The specific gravity can be tested immediately after charging the battery.
Commercially available hydrometerShop towelWhen working with battery acid, make sure to follow all "Warnings
and safety precautions for lead-acid batteries." Wear suitable
protective clothing and eye protection. When disposing of batteries, always comply with applicable
Federal, State and local laws regarding the disposal of batteries
and sulfuric acid. In order to better determine the overall condition of a battery, always
perform a specific gravity test in conjunction with the load test. The temperature of the electrolyte must be at least 10 C (50 F).
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27-15
Use the following procedure to test the specific
gravity in all of the battery cells:

- Switch ignition off.

- Remove all cell caps.

The higher the specific gravity of the drawn electrolyte, the higher the
indicator will float.
The specific gravity of the electrolyte can be read in kg/dm3 on the
hydrometer scale. - Immerse tip of hydrometer into battery cell and draw out enough
electrolyte to allow indicator to float freely.
- Compare measured value indicated on hydrometer to values indicated
in table below:
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27-16

State of charge in normal
climate zones Specific gravity in
kg/dm
3
Discharged 1.12
Half charged 1.20
Good charge 1.28
In normal climate zones, the specific gravity must
be at least 1.24 kg/dm
3.

- If specific gravity is too low: charge battery.

- After charging battery, repeat specific gravity
test.

Note:
The measured values for the specific gravity of
the individual battery cells must not vary by more
than 0.03 kg/dm
3.
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27-17

Examples of unacceptable variations in
specific gravity:

Battery
cell: 1 2 3 4 5 6

Specific gravity per cell in kg/dm
3
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 specific gravity in cell 4 is too low.
Example 2:
The specific gravity in cells 4 and 5 is too low
(the difference in specific gravity between the
cells is greater than 0.03 kg/dm
3).

- If values are not met, replace battery.

- If values are met, reinstall cell caps.
The original cell caps that came with the battery
must be reinstalled to help prevent leakage.
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If the cell caps are lost or damaged, use
replacement cell caps of the same manufacture.
The cell caps must be equipped with an O-ring
seal.
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