Where is the battery?

Always best to check your manual. I have a 06' E350 and it has two batteries. The main battery is in the trunk and you have to remove the spare to access it. The second is a small gelpack battery to maintain electronics and stuff located at the firewall; it is like a small scooter or mower battery. They both went about the same time. Witht he Gel battery I got red warning lights on the instrument display. Can't miss that. Hope this provdes some help. I know it is not for a 2011.

I have a 2011 M-Benz E350 and my battery is under the hood near the firewall on the passenger side. The battery has a black plastic cover on it that you can remove by un-doing three metal clips.