SL Boy

I have just bought a CTEK XS 3600 battery conditioner as I dont use the car much in the winter months so the secondary battery in the truck and occasionally the starter battery have become discharged. It came with battery clips, eyelets and a cigar lighter connector.

Clearly if I want to charge/condition just one of the batteries I can attach the clip or eyelet connectors to the relevant battery. However there are no instructions relating to using the cigar lighter connector (although it is a CTEK product) and I am wondering if it is possible to connect the XS 3600 to the cigar lighter socket and whether it will charge/condition either just the auxiliary or the starter battery or whether it will do both at the same time.

Any help/advice much appreciated. Thanks