Volkswagen Jetta / Bora: Electrical System Manual - part 6

Note

♦

In the battery type “standard charge” the parallel use of con‐

sumers while charging is possible. The charging period will be

longer.

♦

The battery charger will switch to maintenance mode after

about 1-7 hours, depending on type of battery. To achieve a

100 % charge the battery should remain connected for this

period.

Possible faults and fault rectification:
1 - Displayed battery voltage is not as per nominal voltage:
– Press respective button “Up” 

↑

 or “Down” 

↓

 until charging

sequence starts.

2 - Displayed battery voltage is not as per nominal voltage –

charging sequence already started:

– Press 

START / STOP

 twice.

– Press respective button “Up” 

↑

 or “Down” 

↓

 until charging

sequence starts again.

3 - Battery charger does not detect a battery, when battery volt‐

age is less than 2 V:

Display remains unchanged.
The battery type and ampere hours (Ah) as set is displayed.
Ending battery charging sequence:
– Press 

START / STOP

.

– Disconnect black terminal clamp “-” of charger unit from neg‐

ative terminal on battery.

– Disconnect red terminal clamp “+” of charger unit from nega‐

tive terminal on battery.

– Pull charger unit plug out power supply socket.

3.2.3

Charging battery in service mode with

battery charger -VAS 5900-

WARNING

Danger of injury! Observe warning notices and safety regula‐

tions 

⇒ page 2

 !

Caution

The operating mode “service charge” is not permitted on VW

vehicles as the voltage peaks will damage the onboard elec‐

tronics.
If there is a requirement to use “service charge” the battery

must be disconnected from the onboard supply.

Jetta 2005 ➤ , Bora 2006 ➤

3. Charging battery    

21

When charging always set the battery charger to the correct

type of battery ⇒  Operating instructions for battery charger -

VAS 5900- !
“Service charge” must only be used for:

♦ Wet batteries, where distilled water can be replenished.
♦ Gel/absorbent glass mat batteries.

Do not use operating mode “service charge” with maintenance-

free wet batteries 

⇒ page 1

 .

The operating mode “service charge (SERV)” is only used on

suspect defective batteries (e.g. sulphation). The battery will be

charged to maximum specific gravity and the plates will be reac‐

tivated (dissipation of sulphur layer).
Special tools and workshop equipment required
♦ Battery charger -VAS 5900-

Note

♦

The battery must have a temperature of at least 10 °C.

♦

If the battery has cell sealing plugs, do not open them while

the battery is being charged.

– Switch off the ignition and all electrical consumers.
– Connect charger unit plug to power supply. The last selected

operating mode will appear on display 

⇒ page 19

 .

– Set battery to respective operating mode with 

INFO

.

In the display the symbol -1- for “service charge for wet batteries”

or the symbol -2- for “service charge for gel/absorbent glass mat

batteries” will appear.
– Set battery capacity (Ah) of battery for charging using respec‐

tive button “Up” 

↑

 or “Down” 

↓

.

– Connect red terminal clamp “+” to positive terminal on battery.
– Connect black terminal clamp “-” to negative terminal on bat‐

tery.

The charger unit recognises the voltage required for the connec‐

ted battery (6 V, 12 V or 24 V) and initiates the charging sequence.

Jetta 2005 ➤ , Bora 2006 ➤

22

switches to the “final charge” mode. The fourth bar appears in

display -1-. The battery is ready for use.

Note

The success of the “service charge” depends on the severity of

the sulphation of the battery.

Possible faults and fault rectification:
1 - Displayed battery voltage is not as per nominal voltage:
– Press respective button “Up” 

↑

 or “Down” 

↓

 until charging

sequence starts.

2 - Displayed battery voltage is not as per nominal voltage –

charging sequence already started:

– Press 

START / STOP

 twice.

– Press respective button “Up” 

↑

 or “Down” 

↓

 until charging

sequence starts.

3 - Battery charger does not detect a battery, when battery volt‐

age is less than 2 V:

Display remains unchanged.
The operating mode and ampere hours (Ah) as set is displayed.
Ending battery charging sequence:
– Press 

START / STOP

.

– Disconnect black terminal clamp “-” of charger unit from neg‐

ative terminal on battery.

– Disconnect red terminal clamp “+” of charger unit from nega‐

tive terminal on battery.

– Pull charger unit plug out power supply socket.

3.2.4

Charging totally discharged battery with

battery charger -VAS 5900-

WARNING

Danger of injury! Observe warning notices and safety regula‐

tions 

⇒ page 2

 !

Jetta 2005 ➤ , Bora 2006 ➤

3. Charging battery    

23

♦ The terminal polarity protection in operating mode “charg‐

ing totally discharged batteries/support mode” is not ac‐

tive. Connect battery charger terminal clamps correctly to

battery terminals.

♦ When charging always set the battery charger to the cor‐

rect type of battery ⇒  Operating instructions for battery

charger -VAS 5900- !

♦ Totally discharged battery is not recognised by battery

charger 

⇒ page 27

 .

♦ Do not press 

START / STOP

 button when charger unit

cables are connected incorrectly. The charger unit may be

damaged.

Batteries with a voltage of less than 2 Volt will not be recognised

automatically by battery charger -VAS 5900- .
Special tools and workshop equipment required
♦ Battery charger -VAS 5900-

Note

♦

The battery must have a temperature of at least 10 °C.

♦

If the battery has cell sealing plugs, do not open them while

the battery is being charged.

– Switch off the ignition and all electrical consumers.
– Connect charger unit plug to power supply. The last selected

operating mode will appear on display 

⇒ page 19

 .

Jetta 2005 ➤ , Bora 2006 ➤

24