thanks for your Information.
This was and is a Diruptor Problem that only occured once (three years ago) after motoring 3 days non stop with higher rpm. In my case the Diruptor was so "preheated" that after 10 min use of the Watermaker the fuse triggered. Afer arrival and cool down, all back ok....it also never happend again, since I never did this kind of long high rpm crusing...
I had a complete raw water check. All ok. Last year I had to clean and decalc the Onan heat exchanger.
But do you have any Idea how to get the 24v Alternater charging at idle? That's a little annyoing...I don't know it it was always like this or when it started, but I recogniced it about two years ago.