on our 914F engine the generator seems to be producing power, the gen indicator light on the panel goes out. But the battery is not being charged and the ammeter is not showing any reading. 

checked all the relevant relays, and done continuity check on the wiring, all readings as expected. All contacts cleaned. 

engine is in a Dimona HK36TTS


taking multimeter readings with the engine running not easy/possible to do safely  


any suggestion as to next steps most welcome


  • Re: 914F generator/ammeter query

    by » 3 days ago

    Unless the display is Blank;  The Ammeter is never,"... not showing any reading."  Zero is a reading!

    If you see more than 13.8v on the battery, Engine ON, the battery is charging.
    If you see less than 12.6v on the battery, Engine ON, the battery is discharging.
    The ammeter will either display the charging current or the discharge current. Typically 2 to 3 or more amps either way.
    If is does not show a discharge current before starting, Suspect the Ammeter.

    You may need to temporarily extend your meter probes for safety sake.  Any wire will do.
    The B+, R, and C Terminals on the regulator should measure slightly more than the DC Battery Voltage, Engine ON. Ground referenced.
    Most importantly, they should ALL measure the SAME.

    If the Regulator terminals do not match the battery; suspect an open fuse or switch.

    If all else fails, the G terminals on the regulator when disconnected, Engine ON, should measure 10+ volts AC at idle and 20++ volts AC at speed.
    AC not DC!
    Measure from one G wire to the other, not to ground.  (G = Gelb = Yellow in German)

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated by Everyone.

  • Re: 914F generator/ammeter query

    by » 3 days ago

    Point taken re ammeter, it is an analogue dial and perhaps it would be more accurate to say no movement in the needle even when adding to, or reducing the load on the electrical system.


    Thanks for the other thoughts - we will see where we get to.



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