Hi Simon, appreciate your video. I am also mechanic, not to say you are wrong. I have seen Alternator voltage as low as 12.9v for a new alternator ( good belt tension) on a different car. To me, in order to say an Alternator is faulty, under full load and rev with good belt tension and connector, if it less than 13v, then it fail. You might not need to replace it if it more than 13v. I knew it crazy that new alternator output only as low as 12.9 - 13.2v. You would expect as least 13.6v. As long as alternator voltage more than 12.8v under all situation, you might not need to concern about it. Keep up the efforts. I am Vn from Australia.
