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Add resistance to a led tail light? Answered

I have a Led Tail light to wire to my motorcycle. I split my running light to light up my flashers also. My question is how can I make my tail light less bright? I off course think about putting a resistance, but how to choose the right one?

here's my spec:

12V motorcycle battery

Led light: 15 white LEDs

2 flashers: 12 volts incandescent bulbs

Wiring: original running light split in two (1 in tail light and one to the back) then the second one split into the two flashers

Thank you all

Discussions

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iceng

4 days ago

I put two diodes in series with the LED and short the diodes on breaking..
You may need to use three diodes..
This works much better then a wasteful resistor and it is more immune to discharged battery voltage.

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Downunder35m

6 days ago

Just use a voltage regulator.
One with 9V should show a dimming, go to 5V and it is even less.
For a resistor you need the amps the light draws and it will waste a lot of heat.

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ImAtechDownunder35m

Reply 5 days ago

"For a resistor you need the amps the light draws and it will waste a lot of heat"

So does a simple voltage regulator, which is basically a controlled variable resistor. Not much current to worry about with LED's. Use a resistor. KISS!

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Jack A Lopez

5 days ago

How about measuring the current to this LED bulb? Then call that value I. Then 12 volts divided by I, is the size of a resistor that would draw the same current as this LED bulb.

I'm not saying that resistance will be the size you want to put in series with the LED bulb, but I expect the extra series resistance you do want, for dimming purposes, will not be larger than that value.