Thanks, Graham! Yes, I understood that camper battery is on left and car (start) battery is on right (if you sit on the car).
I have warning Auxiliary and I understood, its righ side car battery. This small thing on right side , on behind start battery, is some regulator. On normal V class its additional small battery named auxiliary.
On my C class Mercedes there auxiliary battery is this small box under dash.
I ask, because our country Mercedes distributor not understand MP systems and they are completely out.