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Using jump starting with another battery

If the car does not start, it may be due to the 12V battery being discharged. It can then be charged with the assistance of another car or an external charger.

Under normal conditions, the 12V battery is charged at the same time as the car is charged, as well as via current transmission from the high voltage battery when the car is not connected for charging.

If the 12V battery is discharged for any reason, jump-starting can still be used. This may be caused by the car not being used for a long time, a temporary fault, or a blown fuse in the car's charging circuit, for example. A discharged 12V battery needs to be charged sufficiently in order to be able to start the car's electrical system. After start-up, it is possible to start charging the car using the charging cable, which will be necessary if the high voltage battery is also discharged. If the car is out of reach for charging in such a situation, it may need recovery.

Using jump-starting requires jump leads, which are connected to the charging points for the 12V battery.

Access to the charging points

The protective panel that allows access to the charging points is located front left under the bonnet, and is held in place with fasteners. To remove these fasteners, use a screwdriver, pen or similar to press in the locking pin in the middle of the fastener. When the pin is pressed in far enough, the fastener can be pulled out. Avoid pushing the pin all the way through the fastener, as this could cause it to dislodge and fall down between components. When reinstalling the panel, pull the locking pin out completely before reinserting the fastener. When the fastener is inserted in the attachment hole, push the locking pin into place again to secure the panel.

PS2-2007-Remove panel under hood
Loosen the five fasteners and lift up the panel.

Connecting the jump leads

PS2-2007-Starter cable clamp position
Charging points under the panel. The positive charging point is located furthest back adjacent to one of the car's central electrical units. The negative charging point consists of a bolt in contact with the car's chassis and is located further forward.

 Important

The car's charging points are only intended for jump-starting the car itself. The charging points are not intended for jump-starting another car. Using the charging points to jump start another car may cause a fuse to blow, which means the charging points will stop working.

If the message 12 V battery fuse failure Service required is shown in the driver display then a fuse has blown and needs to be changed.

When jump-starting the car using another battery, the following steps are recommended to avoid short circuits or other damage:

Set the car's electrical system in passive usage mode.
Check that the donor battery has a voltage of 12 V.
If the battery is installed in another car - switch off its engine and make sure that the cars do not touch each other.
Connect one of the red jump lead's clamps to the donor battery's positive terminal, often marked in red or with a plus sign.

 Important

Exercise caution when connecting the jump leads. A short circuit may occur if the ends come into contact with any other surface than the charging points.
Open the cover for the positive charging point by pressing on its side. This disengages a hook and you can lift the cover up at the same time. There are two charging points under the cover, and you should use the one closest to the centre of the car.
Connect the red jump lead's other clamp onto the positive charging point.
Connect one of the black jump lead's clamps to the donor battery's negative terminal, often marked in black or with a minus sign.
Connect the black jump lead's other clamp onto the car's negative charging point. The car's chassis is the grounding point for the 12V-system – which means that the highlighted bolt head in the figure can be used.
Check that the jump lead clamps are affixed securely so that there are no sparks during the starting attempt.
Start the engine of the donor car.
Start the car that has the discharged battery by keeping your foot on the brake and selecting gear position D or R.

 Important

Do not touch the connections between cable and car during the starting attempt. There is a risk of sparks forming.

 Note

Full start-up is indicated by means of the driver display's indicator lamps extinguishing and its preset theme illuminating.
If the high voltage battery is also discharged, start charging the car with the charging cable.

Remove the jump leads in reverse order - first the black and then the red.

Make sure that none of the black jump lead's clamps comes into contact with the car's positive charging point, the donor battery's positive terminal or the clamp connected to the red jump lead.

 Note

A discharged 12V battery needs to be charged for a period of time in order to achieve a sufficiently high State of Charge (SoC) to power the car's electrical system. In an outside temperature of approx. +15 °C (approx. 60 °F), the battery needs to be charged for at least 30 minutes by the car. In a lower outside temperature, the charging time may increase to 3–4 hours. If possible, it is recommended to charge the battery using an external battery charger.

 Warning

  • The battery can generate oxyhydrogen gas, which is highly explosive. A spark can be formed if a jump lead is connected incorrectly, and this can be enough for the battery to explode.
  • Do not connect the jump leads to any fuel system component or any moving part. Be careful of hot engine parts.
  • The battery contains sulphuric acid, which can cause serious burns.
  • If sulphuric acid comes into contact with eyes, skin or clothing, flush with large quantities of water. If acid splashes into the eyes - seek medical attention immediately.
  • Never smoke near the battery.

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