Amongst others, Marine batteries are designed to be deep discharged, (ie: for trolling) and accept a charge differently than a car battery. That's why you will also see battery chargers for sale that are specifically designed for Marine battery applications.
Your Mercedes Charging system was not designed to charge a Marine battery. Stick to a car battery.
Phil
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'95 E300 Diesel, 264,000 Miles. [Sold it]
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