65 Finnie dash light gremlin
 

Hi all - am a newbie here at mercedesshop, so pleased to meet y'all (and please be gentle!! :D). Looking for any ideas/thoughts as to why the charge light remains on although battery charge is fine?

Heckflosse, i've heard when that happens it means you need a new regulator.

Or a diode trio is out within the alternator. A regular charging test machine would not readily pick that up. A faulty diode would allow some charging but not full amperage. The failed diode would also allow some feedback to the dash light and keep it on, sometimes dimly. Find an old established alternator rebuilder and let them rebuild yours. Some big rig truck repair places can repair yours. Check the phone book for large truck repair shops.

Further info...
 

I should probably elaborate a little to avoid the obvious conclusion attached to charge lights that stay on - that the alternator is cactus..!!!

The car was originally fitted with a 2.2Lt mech injected six, which has been politely traded for a 4.5Lt from a 74 model (D Jet) engine.

The original 55 Amp alternator was operational when the conversion was completed and stayed in the car for around 12 months. However, a 108 Amp alternator was sourced as the car has been fitted with some accessories (don't worry guys, the original car has not been destroyed with a stoopidly big radio).

The original wiring was used to connect the new alternator (battery lead- red and paper insulated, earth - back with paper insulation and the trigger wire - pink)

Hoping it is something really simple like a wire has been plugged in wrong, but seems unlikely given that it seems to operate correctly.