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Generator light

Category: General Tech Discussion 4 months ago

The install manual says to use a 3 watt warning light for the generator. Is it ok to use a much lower wattage LED light instead?

  • Re: Generator light

    by » 4 months ago


    What Engine???

    LED lamps will work just fine if configured correctly.

    In some circuits, there is a small residual current that is enough that the LED will never extinguish.

    The addition of a shunt resistor usually resolves this problem.

    . . .

    A 3 watt(250mA) lamp is dark with 20 mA leaking through it.

    That same 20mA will fully illuminate an LED.


    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Bill.Hertzel@Yahoo.com
    Clicking the "Thank You" is Always Appreciated.


    Thank you said by: RotaxOwner Admin

  • Re: Generator light

    by » 4 months ago


    Thanks Bill,

     

    The engine is the 912 ULS. I am also wondering if the warning lamp needs to be connected at all? I am connecting a current inducer to the MGL IEFIS so I will have amps current indication. I know from automotive systems if the warning light is blown it won't charge. Anyone have any insight on a good way to connect this?

    Cheers

    Murray


  • Re: Generator light

    by » 4 months ago


    Using the design example from the 912is installation manual...

    If the  LED of your choice does not already have a resistor in series for 12 volts, a 1,000Ω Resistor (1/2W) in series with the LED will set the current to ~12mA (0.012A).

    If that works, and it probably will, Great!, if not, add a 1.500Ω Resistor in Parallel with the Diode/Resistor pair.


    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Bill.Hertzel@Yahoo.com
    Clicking the "Thank You" is Always Appreciated.


    Thank you said by: Murray Parr

  • Re: Generator light

    by » 4 months ago


    Thanks again Bill,

    I will try that.


  • Re: Generator light

    by » 6 weeks ago


    In the CTSW installation, they used a clever trick to power the hobbs meter. High side from instrument power, low side to the light bulb. That means the instrument on, engine off has the light on and hobbs not running.  When charging starts , the light goes out, and provides a path to ground to operate the hobbs.  A low current LED might not provide that path to ground.

    I don't know if others have used this wiring.

    Bill McCandless


    2006 CTSW,

    912ULS


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