[Teutonic]

I have a question for you guys.

I have washed my X1, give it a polish, some leather treatment and put it in the garage so I can drive my summer car. It's been three weeks since the X1 is sitting in the garage and Saturday afternoon, I decided to wash the garage since the weather was very nice. When I start the X1 the car on the hoist sign appear and then the battery sign appear.
I put the battery to charge with the OEM BMW charger Saturday night and today in the morning (36 hours later) the battery was close to charged since the green LED was blinking but it wasn't full yet.

I don't get it. My Honda was sitting in the garage for 5 months without being started and the battery was top notch. I used to keep my Jaguar for 4-5 months in the garage during the winter, maybe start it for 20 minutes once every 2-3 weeks and never got a problem, what is happening with the X1?
Can the alarm and red nose light suck all the juice from the battery?
It is something abnormal?

A friend use to have a Porsche Cayenne that was draining the battery every night and he need to charge the battery every night to be able to use the car next day. Porsche did not found the trouble ever and kept saying is nothing wrong with it, so he sold the car, never looked back.

Did you guys experienced something similar with your X1?
What is your opinion?
Thanks!