How do I access the consumer battery on the 2008 S 550 4MATIC

 

the main bettery is beahind the wall in the trunk. its not easy to access. usually with the right tools you can pull out the back wall starting at the bottom right hand corner and pull out.but gooing back in is a pain. you really should remove the side trunk liner first. and I belive there are 13mm or 10mm nots at the very top or bottom. not totally sure. been awhile since ive messed with a newer S class battery.