The manual indicates to remove the screw securing the battery and remove the battery support and bracket. Where are these two items located as there is no apparent screw / bracket on the top side of the battery. However, the battery cannot be moved and is obviously locked in place. There is also no obvious screw or bracket looking from underneath the car as well.
Battery Replacement on S500 on 2003 Mercedes-Benz S500 4MATIC
by Visitor in Acworth, GA on November 25, 2010
ANSWER by ZeeTech , November 25, 2010
It's at the bottom part of the battery. Grab a flash light and shine it down, you will see the retainer bracket. You have to remove the bracket and slide the battery a bit and lift it up. Remove the terminals in the following order: Negative, Positive, and install them: Positive, Negative. Make sure the key is not in the ignition, better if you keep it in your pocket. Zee