Volkswagen Jetta / Bora: Electrical System Manual - part 1

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Battery

WARNING

Danger of injury! Observe warning notices and safety regula‐

tions 

⇒ page 2

 !

Caution

To prevent damage to the battery and vehicle, the following

should be observed concerning types of battery 

⇒ page 1

 .

1.1

Fundamentals for batteries

To ensure long use of the battery, the battery must be checked,

serviced and maintained as per instructions in this Manual.
Apart from supplying energy for starting the engine, the battery

has other tasks: it acts as a buffer and supplies electrical energy

to the complete vehicle electrical system.

Note

Observe ⇒ Self-study programme  No.  234 ; vehicle batteries .

1.2

Types of battery

1.2.1

Low maintenance battery

Low maintenance battery with liquid electrolyte (wet battery).

These batteries are recognised by the removable cell plugs.
Lead-acid battery, electrolyte level must be checked regularly and

topped-up with distilled water as required.
These batteries are often equipped with a magic eye. The magic

eye provides information concerning the level of the electrolyte

and the charge state of the battery.

1.2.2

Maintenance-free battery

Maintenance-free battery with liquid electrolyte (wet battery).

These batteries have a cover over the cells instead of cell plugs.

The cover seals the battery after initial filling during production.

Caution

Never under any circumstances remove the cover for the bat‐

tery cells. The battery housing will be damaged and the battery

is therefore unusable.

Lead-acid battery, where electrolyte need not be topped-up with

distilled water under normal conditions. This term is normally used

for batteries with a predetermined amount of electrolyte.

Jetta 2005 ➤ , Bora 2006 ➤

1. Battery    

1

eye provides information concerning the level of the electrolyte

and the charge state of the battery.

1.2.3

Absorbent glass mat (AGM) battery

Maintenance-free battery with a contained electrolyte.
Lead-acid battery where the electrolyte is contained within a mi‐

croscopic glass mat (AGM). The battery is sealed and fitted with

valves.
AGM is the abbreviation for Absorbent Glass Mat.

Note

♦

The procedure for checking and testing gel and absorbent

glass mat batteries is identical.

♦

Always replace an absorbent glass mat battery with another

absorbent glass mat battery.

1.2.4

Gel battery

Maintenance-free battery with a contained electrolyte.
Lead-acid battery where the electrolyte is contained within a gel.

The battery is sealed and fitted with valves.

Note

♦

The procedure for checking and testing gel and absorbent

glass mat batteries is identical.

♦

Currently gel batteries are only used in motor homes/campers

at Volkswagen.

1.3

Warning notices and safety regulations

1.3.1

Dangers when handling vehicle batter‐

ies

Recognition and avoidance of dangers
Batteries can be dangerous. These dangers can be avoided when

the warnings on the battery and in the owners/instruction manual

and in ELSA are observed.

Jetta 2005 ➤ , Bora 2006 ➤

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♦ Untrained personal e.g. apprentices, trainees etc. may

only work on batteries when supervised by a vehicle me‐

chanic/foreman or vehicle electrician/foreman.

♦ Acid is highly corrosive. There is a considerable danger of

acid burns if personal do not handle batteries correctly.

Therefore suitable measures must be taken to ensure that

equipment/solutions etc. are available to neutralize acid

burns. A suitable solution is: e.g. a soap solution.

♦ If electrolyte leaks from a battery it may cause skin burns

and acid corrosion, rusting on the vehicle. This may dam‐

age safety relevant components on the vehicle.

♦ The gas which forms when charging and the gas which

may escape through vent valves is explosive. In extreme

cases a battery may explode if the battery is not handled

correctly.

♦ It is prohibited to cause sparks through grinding, welding,

cutting operations and use naked lights in the vicinity of

batteries. Smoking is also prohibited. Sparks must also

prevented through electrostatic discharge, therefore al‐

ways earth through vehicle body etc. before touching

battery.

♦ Only work on batteries in well ventilated and suitable

rooms.

1.3.2

Safety markings on battery

Safety markings on battery
1. - Fires, sparks, naked lights and smoking are prohibited. Avoid

sparks as well as electrostatic discharge when working with ca‐

bles and electrical units. Avoid short circuits. Therefore never lay

a tool on a battery.
2. - Wear eye protection before commencing work on battery.
3. - Keep children away from acid and batteries.
4. - Disposal: old batteries are classed as hazardous waste. They

may only be disposed of through a suitable collection centre and

only in accordance with respective legislation.
5. - Never dispose of old batteries in household waste system!
6. - There is a danger of an explosion when working with batteries.

A highly explosive gas is produced when batteries are charged.
7. - Follow instructions concerning batteries, in ELSA "electrical

system" and in owner's manual.
8. - Battery acid is very caustic, therefore wear eye protection and

gloves when working with batteries. Do not tilt battery. Acid can

leak out of the gas vents of some batteries.

Jetta 2005 ➤ , Bora 2006 ➤

1. Battery    

3

Battery terminal connection

Caution

To prevent damage to the battery terminal clamps and battery

terminals, the following should be observed:

♦ The battery terminal clamps should only be fitted by hand

and without using force.

♦ Battery terminals should not be coated with grease.
♦ The battery terminal clamps should be fitted so that the

battery terminal is either flush with the clamp or protruding

from it.

♦ Once the battery terminal clamps have been tightened to

the specified torque, the threaded connections should not

be tightened any further.

The tightening torque for the battery terminal clamps -1- and the

additional clamps-2- can be found in this table “Tightening tor‐

ques: Battery” 

⇒ page 36

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Jetta 2005 ➤ , Bora 2006 ➤

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