Get Checking and refilling -> 12-volt vehicle battery Guide for Volkswagen E Golf 4 Door Second Generation (2017-2020)

12-volt vehicle battery

Introduction to the topic

The 12-volt vehicle battery is a component of the electrical system and in event of the high-

voltage system failing, supplies the safety-relevant systems of the vehicle with energy. In the

scope of maintenance work, the 12-volt vehicle battery is checked and where required, replaced.

You should only carry out work on the electrical system if you know exactly how to perform the

required tasks, are aware of the general safety procedures and have access to the correct

equipment, service fluids and suitable tools. Failing to carry out work correctly can cause serious

injuries → . All work should be carried out by a qualified workshop. Volkswagen recommends

using a Volkswagen dealership for this purpose.

Information on warning and indicator lamps that light up can be found in the troubleshooting

sections at the end of the chapter (→ 12-volt vehicle battery, FAQ).

Location of 12-volt vehicle battery

The 12-volt vehicle battery is located in the engine compartment.

Explanation of the warnings on the 12-volt vehicle battery

Always wear eye protection!

Electrolyte is very corrosive and caustic. Always wear protective

gloves and eye protection!

No fire, sparks, naked lights or smoking!

A highly explosive mixture of gases is given off when the 12-volt

vehicle battery is charging!

Always keep children away from electrolyte and the 12-volt vehicle

battery!

Always observe the owner's manual!

WARNING

Any work on the 12-volt vehicle battery and the electrical system can cause serious chemical

burns, fire or electric shocks. Always read the following warnings and safety information before

carrying out any kind of work:

●

Switch off the ignition and all electrical consumers before carrying out any work on the 12-

volt vehicle battery and also disconnect the negative cable from the 12-volt vehicle battery.

●

Children should always be kept away from electrolyte and the 12-volt vehicle battery.

Always wear eye protection and protective gloves.

Electrolyte is very aggressive. It can burn the skin and can cause blindness. When working

with the 12-volt vehicle battery, ensure that your hands, arms and face in particular are

protected from acid spillage.

●

Do not smoke during the work, and never work near naked flames or sparks.

When handling cables and electrical equipment, avoid generating sparks and electrostatic

charge.

●

Never short circuit the battery terminals.

Never use a damaged 12-volt vehicle battery. It can explode. Damaged 12-volt vehicle

batteries must be replaced as soon as possible.

●

Never use a frozen 12-volt vehicle battery. Discharged 12-volt vehicle batteries can already

freeze at temperatures of around 0°C (+32°F). Frozen 12-volt vehicle batteries must be

replaced immediately.

NOTICE

Do not expose the 12-volt vehicle battery to direct daylight for an extended time.

●

The ultraviolet radiation can damage the battery housing.

NOTICE

Protect the 12-volt vehicle battery against frost if the vehicle is left standing for extended

periods.

●

The 12-volt battery can freeze and be destroyed as a result.

When you activate the vehicle’s drive system after the 12-volt battery has been totally

discharged or replaced or after a successful jump start, you may find that system

settings (time, date, personal convenience settings and programming) have been

changed or deleted. Check and correct the settings as necessary once the 12-volt vehicle

battery has been sufficiently charged.

Checking the electrolyte level of the 12-volt vehicle battery

Fig. 1 Battery window on the top of the 12-volt vehicle battery (illustration).

The electrolyte level of the 12-volt vehicle battery should be checked regularly in high-mileage

vehicles, in hot countries and in older 12-volt vehicle batteries. The 12-volt vehicle battery is

otherwise maintenance-free.

Preparations

—Preparing the vehicle for working in the engine compartment (→ In the engine compartment,

Description).

—Open the bonnet (→ In the engine compartment, Operation).

Checking the electrolyte level (12-volt vehicle batteries with battery

window)

—Ensure that enough light is available for you to clearly see the colour indicator in the round

battery window on the top of the 12-volt vehicle battery (arrow) → Fig. 1 . Never use naked

flames or glowing objects as a light source.

—The colour displayed in the round battery window changes according to the electrolyte level in

the 12-volt vehicle battery.

Light yellow or without colour The electrolyte level of the 12-volt vehicle battery is too low. The

12-volt vehicle battery should be checked and replaced by a

qualified workshop if necessary.

Black

The electrolyte level of the 12-volt vehicle battery is correct.

WARNING

Any work on the 12-volt vehicle battery can cause serious chemical burns, explosions and

electric shocks.

●

Always wear eye protection and protective gloves.

●

Electrolyte is very aggressive. It can burn the skin and can cause blindness. When working

with the 12-volt vehicle battery, ensure that your hands, arms and face in particular are

protected from acid spillage.

●

Never tilt the 12-volt vehicle battery. Electrolyte may spill out of the battery vents and

cause chemical burns.

●

Never open a 12-volt vehicle battery.

If acid is spilt in your eye or on your skin, rinse immediately for several minutes with cold

water. Then consult a doctor immediately.

●

If electrolyte is swallowed, consult a doctor immediately.

Charging, replacing, disconnecting and connecting the 12-

volt vehicle battery

If you suspect that the 12-volt vehicle battery is damaged or faulty, go to a qualified workshop

and have the 12-volt vehicle battery checked.

Charging the 12-volt vehicle battery

The 12-volt vehicle battery should be charged by a qualified workshop, as the technology used in

factory-fitted 12-volt vehicle batteries requires voltage-limited charging → . Volkswagen

recommends using a Volkswagen dealership for this purpose.

Replacing the 12-volt vehicle battery

The 12-volt vehicle battery has been developed to suit the conditions of its installation location

and has special safety features. If a 12-volt vehicle battery has to be replaced, discuss the

electromagnetic compatibility, size and necessary servicing, output and safety requirements for

the new 12-volt vehicle battery with a Volkswagen dealership before purchase. The ventilation

opening of the 12-volt vehicle battery must always be on the negative terminal side: the

ventilation opening on the positive terminal side must always be sealed.

Only maintenance-free 12-volt vehicle batteries compliant with the standards TL 825 06 and

VW 7 50 73 should be used. These standards must be dated October 2014 or later.

Always have the 12-volt vehicle battery replaced by a qualified workshop, as the vehicle

electronics must be adapted as part of the replacement process. Only qualified workshops have

the technology required to carry out this adjustment correctly. Volkswagen recommends that the

12-volt vehicle battery is replaced by a Volkswagen dealership.

Disconnecting the 12-volt vehicle battery

Please observe the following if the 12-volt vehicle battery has to be disconnected from the

electrical system in the vehicle:

—Switch off all electrical consumers and the ignition.

—Unlock the vehicle before disconnecting the battery in order to avoid triggering the anti-theft

alarm.

—First disconnect the negative cable and then the positive cable →

.

Connecting the 12-volt vehicle battery

—Switch off all electrical consumers and the ignition before reconnecting the 12-volt vehicle

battery.

—First reconnect the positive cable and then the negative cable →

.

Various indicator lamps may light up after the 12-volt vehicle battery has been connected and

the ignition is switched on. They will go out if you drive a short distance at a speed of

approximately 15 – 20 km/h (10 – 12 mph). If the indicator lamps remain lit up, the vehicle

should be checked by a qualified workshop.

If the 12-volt vehicle battery was disconnected for an extended period, the system may not able

to calculate or correctly display the time when the next service is due (→ Instrument cluster,

Description). Observe the maximum permissible service intervals (→ Maintenance, Description).

Vehicles with Keyless Access: (→ Keyless Access, Description): if the ignition cannot be switched

on after connecting the 12-volt vehicle battery, lock and unlock the vehicle from the outside.

Then try to switch on the ignition again. Please seek expert assistance if the ignition cannot be

switched on.

Automatic switch-off for electrical consumers

The intelligent vehicle electrical system automatically implements a range of measures to

prevent the 12-volt vehicle battery from discharging under high loads:

—The performance of large electrical consumers may be reduced or they may be switched off

completely.

The vehicle electrical system cannot always prevent the 12-volt vehicle battery from discharging.

For example when the ignition is switched on for an extended period with the engine off, or

when the side or parking lights are on when the vehicle is parked for an extended period.

12-volt vehicle battery is discharged

—Through use of electrical consumers when the vehicle’s drive system has been deactivated.

WARNING

Incorrectly securing the battery and using incorrect 12-volt vehicle batteries can cause short

circuits, fire and serious injuries.

●

Always use maintenance-free and leak-proof 12-volt vehicle batteries that have the same

properties, specifications and dimensions as the factory-fitted 12-volt vehicle battery.

WARNING

A highly explosive mixture of gases is given off when the 12-volt vehicle battery is being

charged.

●

12-volt vehicle batteries should only be charged in well-ventilated spaces.

●

Never charge a 12-volt vehicle battery which is frozen or has been frozen. Discharged 12-

volt vehicle batteries can already freeze at temperatures of around 0°C (+32°F).

●

The 12-volt vehicle battery must be replaced if it has ever frozen.

Incorrectly connected cables can cause a short circuit. First connect the positive cable and

then the negative cable.

NOTICE

●

Never connect equipment that supplies electric power, such as solar panels or a battery

charger, to the 12-volt socket or to the cigarette lighter to charge the 12-volt vehicle

battery. This can damage the vehicle electrical system.

12-volt vehicle batteries may contain toxic substances such as sulphuric acid and lead.

Dispose of the 12-volt vehicle battery in accordance with the relevant regulations.

Electrolyte can pollute the environment. Clean up any service fluid leakages and dispose of

them properly.

Troubleshooting

12-volt vehicle battery

The indicator lamp lights up red and the text message

displayed.

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Do not continue driving! Stop the vehicle as soon as possible and when safe to do so.

The 12-volt vehicle battery will not be charged while the vehicle is in motion.

—Switch off any electrical consumers that are not required.

—Inform a qualified workshop.

—Have the electrical system checked.

12-volt vehicle battery

The indicator lamp lights up yellow and the text message

! is displayed.

Fault in the connection between the vehicle electrical system and the 12-volt vehicle battery.

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If the vehicle’s drive system is deactivated in this situation it cannot be switched back on again.

Start the vehicle using jump leads if necessary (→ Jump starting, Description) or seek expert

assistance.

—Go to a qualified workshop.

—Have the electrical system checked.

12-volt vehicle battery

The indicator lamp lights up yellow and the text message

! is displayed.

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Fault in the system for monitoring the 12-volt vehicle battery.

—Go to a qualified workshop.

—Have the electrical system checked.

12-volt vehicle battery

The indicator lamp lights up yellow and the text message

! is displayed.

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:

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The 12-volt vehicle battery has almost reached the end of its service life.

—Go to a qualified workshop.

—Have the 12-volt vehicle battery checked and replaced if necessary (→ 12-volt vehicle battery,

Replacing).

12-volt vehicle battery

The indicator lamp lights up yellow and the text message

! is displayed.

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Fault in the connection between the vehicle electrical system and the 12-volt vehicle battery.

—Go to a qualified workshop.

—Have the electrical system checked.

12-volt vehicle battery

The indicator lamp lights up yellow and the text message

displayed.

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12-volt vehicle battery has poor charging capacity, caused for example by low temperatures.

—Drive a short distance to recharge the 12-volt vehicle battery.

Checking and refilling -> 12-volt vehicle battery for Your Volkswagen E Golf 4 Door Second Generation (2017-2020)

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