Dynamo and LED. For posterity

[abowie]

There is a thread of mine on battery charging failure in my 3.8.

viewtopic.php?f=3&t=22046

For posterity I eventually found that the problem was caused by my using a LED globe on the alternator light on the dash.

The alternator light connection feeds power to the field coil in the dynamo. With the LED which is a diode not enough power was getting to the field coils and so they wouldn’t energise.

I replaced the dynamo with a Dynamator. It also failed to charge when the car was started although would sometimes start working after maybe 5 minutes.

The Dynamator needs a minimum 2.8W incandescent globe to power the field coils.

Hopefully this saves someone else from the very frustrating time I’ve had trying to nut this out.