starting problem
 

I have a 300e 92............ have started to experience a starting problem..... The car will start fine for weeks then all of a sudden the battery is dead.......... Once it is jumped thing are back to normal.......... this has happen several times....... the terminals are fine and the alternator appears to be working fine too. One thing that I noticed last night was that my dash lights flickering when my foot is on the brake (doors, window switches,and heater controls) This morning it started fine

This test is not specific to Mercedes, it is called potential for draw.
This test will show you if there is anything drawing power while the car is not running. Make sure doors are closed and no lights are on.

Remove the negative lead of the battery

Place a volt meter between the negative terminal of battery and removed negative cable.

If there is something drawing power you will see a voltage reading.

To isolate begin pulling fuses until you determine where the
draw is.

If there is no draw you can open a door to turn on dome lights to determine that the test is working.

The first thing to do is check the battery voltage with the engine off and then with the engine on. If you do a search on this forum, you'll find the acceptable values, particularly for when the alternator is charging the battery.

It sounds to me like your alternator is not fully recharging your battery. If so, it might just need new brushes.