Mercedes-Benz has long been known for their aluminum V* engines. The 3.8 L (116.96), 5.0 L (177.96) and other aluminum Benz engines are surprisingly durable, especially when compared to the older 4.5 liter cast iron engines.
The lady mystery writer from Maine, and the cigar smoking detective in the trashed out trench coat who listen carefully for 58 minutes, and then solve the mystery in the dying moments before the last commercial?
After properly charging and testing the battery, you’ve eliminated it as the source of the problem. The alternator charging rate also looks good. So what caused the dead batter?