I have a BMW Solar Battery Charger ($290 from BMW!!) which the instructions say should be plugged into the "electronic socket". I'm using this in a 2000 X5 4.4.

My question is, where is the electronic socket? Is it the cigarette lighter, which would make sense given it's in the front and this charger lies on the dash (then why wouldn't they say so). Is it the socket in the passenger foot well? I can stand on my head to plug it in I suppose. Is it one of those sockets in the back.

Anyone got any experience of these things and BMW double-speak or do I just plug it into the lighter and see what happens, but then how do I measure what's happening.