More Charging Issues

I have 912ULS on a Zenith Cruzer that is 5 years old and 450+ Hrs.  EarthX ETV680C battery.

 Charles had a 5/29/19 post in this forum about a charging issue problem. He swapped out the voltage regulator with a new one and solved the issue. 

About two weeks ago my amp readings started to bounce around from - 2A to + 8A. Previously, the normal was zero amp reading and 13.9 battery voltage.  The -2A is the normal when engine not running.

Most recently, on a one-hour flight, it was a steady -2A with a slow battery voltage drop. I'm thinking a voltage regulator issue.

Any other ideas?

Jay

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Replies to This Discussion

Permalink Reply by Matt Pope on October 31, 2025 at 10:40am

This troubleshooting guide seems pretty comprehensive and easy to understand: https://pointsforpilots.blogspot.com/2012/12/testing-rotax-912914-g...

Permalink Reply by Stuart Brooks on November 13, 2025 at 5:43pm

one thing to try before replacing it is to check that the regulator is grounded correctly with a dedicated wire from the regulator case to your main grounding point. A bad ground connection could cause the symptoms you are experiencing.

Permalink Reply by Jay M. Johnson on Thursday

After trouble-shooting using the guide mentioned by Matt and talking to locals who have Rotax engines, decided to replace the voltage regulator. Same issue, -2A discharge.  More trouble-shooting and found a heavily corroded inline fuse between the capacitor and the ammeter shunt.  Replaced fuse and ran-up engine.  Problem solved, I think.  Volts and amps are acting like they should.  Weather too poor to go flying to test in the air. 

Permalink Reply by Matt Pope on Friday

Interesting! Thanks for posting the followup. I hope that's the end of the problem.

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