40A Rotax alternator no longer charging battery

All 

As a reference here is the Rotax wiring diagram if you are running both an alternator and a generator together.  Found in the installation manuals. 

Cheers

Thanks for the documents. The internal and external buses are properly separated. Bus separation also, I think, doesn't explain any of the symptoms or observation.

I had a similar problem with the external alternator. It wasn’t diodes or a wiring issue and took me months to figure out. The 12 volt wire that energized the alternator has a plastic clip retaining it to the alternator. Vibration was causing it to break contact. I removed the plastic housing, installed a new bare metal spade connector and bedded it in RTV. That was over a year ago and it charges at 13.9 volts all the time now. Hope this helps.

Ed

Ed Midgley wrote:

I had a similar problem with the external alternator. It wasn’t diodes or a wiring issue and took me months to figure out. The 12 volt wire that energized the alternator has a plastic clip retaining it to the alternator. Vibration was causing it to break contact. I removed the plastic housing, installed a new bare metal spade connector and bedded it in RTV. That was over a year ago and it charges at 13.9 volts all the time now. Hope this helps.

Ed

I had a very similar problem on my oil sensor. I will definitely give this a look.

Did you not see a flickering lamp light because of the vibration?

My plane doesn’t have an alternator light. My only clue was voltage drop which flashes red on my G3X