Can LED bulbs be safely used in motorcycles without additional modifications?

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SUMMARY

Using LED bulbs in motorcycles powered by AC from a magneto generator is feasible, but requires careful consideration of the electrical system. LEDs must be compatible with the voltage and current specifications, specifically rated for 6 VDC. Additional components such as current limiting resistors and flyback diodes may be necessary to ensure safe operation and prevent damage from electrical noise. Modifications should be approached with caution, as improper changes can lead to safety hazards.

PREREQUISITES
  • Understanding of AC and DC electrical systems
  • Knowledge of LED specifications and compatibility
  • Familiarity with motorcycle wiring diagrams
  • Basic electronics components, including resistors and diodes
NEXT STEPS
  • Research the specifications for 6 VDC LED bulbs suitable for motorcycle use
  • Learn about current limiting resistors and their application in LED circuits
  • Investigate the function and installation of flyback diodes in AC circuits
  • Study motorcycle electrical systems and safety standards for modifications
USEFUL FOR

Motorcycle enthusiasts, electrical engineers, and DIY modifiers looking to upgrade lighting systems safely and effectively.

John1397
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I have a small motorcycle and have changed the incandescent bulbs to LED. It seems the bulbs were powered by AC off the magneto generator and AC thru the rectifier powered the 6 volt battery.
Is it ok to run LED this way or should I add diodes like in option a or b of diagram?
 

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LEDs and their supporting circuitry, come in many forms. You can buy LEDs for AC or DC and for many voltage levels. You need to find one that fits the way you want to power it.
 
Option C.

Put a current limiting resistor in series with the LED. At least if this is an indicator light.

If it's a brighter light (headlamp, tail light, etc.) you might want to consider more energy efficient options.

You might also need a flyback diode (option A) if the line is noisy from the spark plug.
 
Option 0.

If your LED units are rated at 6 vdc, you are set. They'll just blink imperceptibly fast.

Your options A & B in your first image make little sense to me. Option A looks like a short circuit.

Is the second image a diagram of your motorcycle's wiring?
 
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Likes Jeff Rosenbury
On second thought, I have to agree with OmCheeto here. :blushing: You do not have the required background to be making this modification. The parts need to be selected with the right values. Additional parts may be needed (such as a blocking capacitor for the flyback if a flyback is needed). And then there's the safety issue of modifying something away from the manufacturer's specifications.

We really can't reverse engineer equipment we can't see when people may be harmed by our decisions.
 
Most likely this can only be answered by an "old timer". I am making measurements on an uA709 op amp (metal can). I would like to calculate the frequency rolloff curves (I can measure them). I assume the compensation is via the miller effect. To do the calculations I would need to know the gain of the transistors and the effective resistance seen at the compensation terminals, not including the values I put there. Anyone know those values?

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