When the car was running, I decided to measure the voltage across the battery and it read 17.2 volts.
I had made a rookie mistake when connecting the 2 wires to the external voltage regulator and got them the wrong way round, despite making a note of where they were supposed to be !
Did a bit of reasearch and discovered that the D+ and DF terminals are marked on the Alternator and also on the RE55 external Voltage regulator so that idiots like me don't make a mistake and fry the regulator. so the tip is check the markings if in any doubt.
The markings on the alternator are not immedialy apparent but with some degreaser on a rag, a mirror and possibly a magnifying glass, you can get to see the terminal markings.
I changed the connections over and ran the car and amazingly got 14.2 volts with revs and bit less at idle. so it seems that I was lucky.
My car is a 1982 Aus delivered Beta coupe with this type of alternator with seperate Voltage regulator as shown
