We had 2 W220 S-Class and several W202 C-Class batteries blow up here at the dealership. All were low on water and out-gassing.
The trunk would be full of gas and the owner or (unlucky tech) would open the trunk and drag a bag or golfbag across the trunk carpet.
Spark....BOOM!!!!
Remember the recall in those 2 cars to check the batteries, install warning labels, and put a anti-static cover in S/CL cars? that was partly because of us.
They were all Hopekke and not Varta batteries.
Wow, what a mess that made in the trunk.
Recently, one of my lot attendants was rounding up old batteries.
There was an old dead one on the floor for a few days. (very sulphated).
He moved it and boom!! Plastic case cut his arms and he got sprayed with
acid.
He was ok, but this dead battery hadn't been touched in days.
It was a time bomb.
I now always wear a full face shield when touching these things.
Luckily, the new AGM batteries will make checking battery water a thing of the past. These Black Gel Batteries are tough and reliable, but spendy!
If you have a traditional Lead-Acid battery, check your water levels every
year or 12k mi. If you have a Hot Charging system (14.7V or higher) check it sooner. Do Not overfill the batteries however. They will boil acid out the caps and vents and kill your Battery tray and everything under it. (W124 owners. This can cause you extra heart-ache!)
Best Regards
DR.D

__________________
Dr.Diesel -
Shop Foreman
Master Guild Mercedes-Benz Technician.

Think the dealer is expensive? Do you know how much it costs to train a dealer tech? Or buy the required MB special tools to have on hand?