Conserving electrical current

Keep the following in mind to help minimize battery drain:
• When the engine is not running, avoid using ignition mode II. Many electrical systems (the audio system, the optional navigation system, power windows, etc) will function in ignition modes 0 and I. These modes reduce drain on the battery.
• Please keep in mind that using systems, accessories, etc., that consume a great deal of current when the engine is not running could result in the battery being completely drained. Driving or having the engine running for approximately 15 minutes will help keep the battery charged.
• The optional 12 volt socket in the cargo area provides electrical current even with the ignition switched off, which drains the battery.
See also:
Dimensions–S60
...
Low battery voltage
If the battery voltage is too low, the parking
brake cannot be applied or released. Connect
an auxiliary battery if the battery voltage is too
low, see page 114. ...
Precautions when the vehicle is being towed
Attach jumper cables (see page 116) to provide current for releasing the
electric parking brake and to move the gear selector from the P position to
N.
Be sure that the steering wheel lock ...
