Remove seat!
main battery is in the boot (trunk) on the drivers side, under a removable panel.
It is under the drivers seat (UK) spec Mercedes ML (W164)It is beside the main battery
My 2005 SLK350 has a +ve connector under the bonnet. Its under a red plastic enclosure and has a hinged cover on it. Just access this connector and clip on your charger. You shouldn't need to access the battery.
The battery to your E class is located under the rear seat. There are two "clips" that are located on the sides of the rear seats, pull those to access the battery.
It is under the rear passenger seat. You have to remove the seat to gain access. If you bend low and look under the front of the seat you will see the mechanism to remove the seat.
Depends where it's located. My 1980s battery is inside the rear compartment under the small access door behind the drivers seat.
There is one under the drivers seat (UK spec vehicles) & one in the boor behind the RHS panel.
The batter is under the passenger front seat. Slide it forward as much as possible and have at it.
Battery is under the rear seat
On an 2011 mercedes Ml 350 the battery is located under front passenger seat
battery is located under the rear seat
Take the left (drivers side) tire off and access the battery inside the wheel well under neath the wheel well liner.