Aha !
That explains why generator switch was on when machine came back from a flight by a Eurocopter pilot then...
As I just pressed all three buttons and then started, I actually turned it (the gen) off for the start and then back on when I saw no charge after the start.
Owner once told me that a 'general parameter' yellow caution warning that comes and goes is due to him doing the same once and starting without the generator on - does that sound right ?