61 12... General information on intelligent battery sensor (IBS): Notes
NOTE:
Do not connect continuous trickle charger to the cigarette lighter.
The cigarette lighter is powered by the rear distribution box via a relay. This relay drops out after terminal 15 OFF. This means that a continuous trickle charger connected to the cigarette lighter is disconnected from the battery.
Charge the battery via the jump-start connection points. Only then can the power supply be registered by the vehicle.