Support battery

Cars with Start/Stop function, in addition to the starter battery, are equipped with a support battery.

Cars with the Start/Stop function are equipped with two 12 V batteries - one extra powerful starter battery for starting and one support battery that helps during the Start/Stop function's starting sequence.

P5-1507 Support battery location
The support battery is located in a box next to the strut tower.

The following table shows specifications for the support battery.

Voltage (V)12
Cold start capacity1 - CCA2 (A)170
Size , L×W×H (mm)150×90×130
Capacity (Ah)10


When replacing the starter battery or support battery, a battery of AGM3 type must be fitted.


  • The higher the current take-off in the car, the more the alternator must be working and the batteries charging = Increased fuel consumption.
  • When the capacity of the starter battery has fallen below the lowest permissible level then the Start/Stop function is disengaged.

Temporarily reduced Start/Stop function due to high current take-off means:

  • The engine auto-starts without the driver lifting his/her foot from the foot brake pedal.

The support battery normally requires no more service than the normal starter battery. A workshop should be contacted in the event of questions or problems - an authorised Volvo workshop is recommended.


If the following instruction is not observed then the Start/Stop function may temporarily cease to work after the connection of an external starter battery or battery charger:

  • The negative battery terminal on the car's starter battery must never be used for connecting an external starter battery or battery charger - only the car's negative charging point may be used as the grounding point.


If the starter battery has become so discharged that everything is "black" and in principle the car does not have all the normal electrical functions and the engine is subsequently started using an external battery or battery charger, then the Start/Stop function will be activated. It will then be possible for the engine to be auto-stopped but in the event of an auto-stop the Start/Stop function may fail to auto-start the engine due to inadequate capacity in the starter battery.

The battery must first be charged in order to ensure a successful auto-start after an auto-stop. At an outside temperature of +15 °C the battery needs to be charged for at least 1 hour. At a lower outside temperature a charging time of 3-4 hours is recommended. The recommendation is that the battery is charged using an external battery charger.

If this is not possible then the recommendation is to temporarily deactivate the Start/Stop function until the starter battery has been adequately recharged.

  1. 1 According to EN standard.
  2. 2 Cold Cranking Amperes.
  3. 3 Absorbed Glass Mat.