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 starting, 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.
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 for jump starting 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. Volvo recommends that an authorised Volvo workshop should be contacted.
Several of the panels around the storage area need to be loosened for access to the charging points under the bonnet.
When jump starting the car, 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 (1).
Exercise caution when connecting the starter cables. A short circuit may occur if the ends come into contact with surfaces other than the charging points.
Open the cover (2) 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 connection points under the cover. Use it closest to the centre of the car.
Connect the red jump lead's other clamp onto the car's positive charging point (2).
Connect one of the black jump lead's clamps to the donor battery's negative terminal (3).
Connect the black jump lead's other clamp onto the car's negative charging point (4).
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.
Do not touch the connections between cable and car during the starting attempt. There is a risk of sparks forming.
Full starting 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 clamps on the black jump lead come into contact with the positive charging point on the car, the positive terminal on the donor battery, or the clamps on the red jump lead.
A discharged 12 V battery needs to be charged for a period of time to reach a sufficiently high State Of Charge (SoC) in order 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 use an external battery charger to charge the battery.
- The 12 V 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.
- The 12 V 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.