It may go off for the whole time, it may never turn off. Those things are like
Hand Grenades. We pack towels and fender covers around them while they are mis-behaving. If you can't get it to turn off after 30 minutes of charging,
it may need to be replaced.
Here in the shop, we had fully charged ones go off for 6 hours!!!
The only thing that stops them is a sledgehammer. They go off under water
too. (we tried that first!

)
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?