# Installing LED headlights



## Coaltrain22 (Aug 5, 2018)

I have a B'mann Consolidation with an Airwire900 board powered with a 14.8v battery. I want to install a 5mm LED headlight but don't know what size resister to install. any help would be appreciated


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## armorsmith (Jun 1, 2008)

Coaltrain22,

Here is the calculator provided on DigiKey's site https://www.digikey.com/en/resource...ors/conversion-calculator-led-series-resistor

You will be able to purchase both the LED and the resistor there.


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## LGB333$$$$ (Oct 11, 2017)

*LED Source*



Coaltrain22 said:


> I have a B'mann Consolidation with an Airwire900 board powered with a 14.8v battery. I want to install a 5mm LED headlight but don't know what size resister to install. any help would be appreciated


Do a search on Amazon.com...........I bought LEDs from a vendor very reasonably priced with the needed resistor already inserted in one of the for each LED. Reduces the work to insert them yourself in the wires


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## East Broad Top (Dec 29, 2007)

I've always used 1K ohm resistors with my LEDs. Those tend to work up through all the track voltages common to large scale. If you know you're going to be running on lower voltages (battery power, for example) you can use lower-value resistors, but you don't really save anything by doing so--except time if you can't find your blasted stash of 1K ohm resistors and can only find 680 ohm resistors. (Purely hypothetical situation, mind you.) 

Later,

K


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## Dan Pierce (Jan 2, 2008)

A 1k resistor on a 10ma led is not enough!!


10 ma leds need 100 ohms for each volt dropped.
20 ma leds need 50 ohms for each volt dropped.


So, a 24 volt source with a 2 volt led at 10 ma needs 22 volts times 100 ohms, 2200 ohms!!!!


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## East Broad Top (Dec 29, 2007)

I push 20ma through mine without trouble, so that's why 1K works for me. I source them from "warm white" strands of Christmas lights. Hit the after-Christmas sales. You can walk out with 1000 LEDs for $10. 

Later,

K


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## Martan (Feb 4, 2012)

I use these little guys all over the place. In my battery locomotives and outside in my buildings. I run 12v to all my buildings and do 14.8 in my locos. They hook directly to the 12/14v and automatically drive the proper current to the LEDs. I can usually power about 3-4 LEDs with one of these.



https://www.mouser.com/ProductDetail/689-CL2N3-G


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## Dan Pierce (Jan 2, 2008)

Martan. the CL2 does limit current to 20ma and if you use 20 ma leds in series it works great, no resistor values to figure out.


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## Martan (Feb 4, 2012)

Yeah, I never use resistors anymore. Too much math! ha. I order the CLs in bulk from mouser. Great little devices.


I also do the LED strings like Kevin said, Lowes and Home Depot have the warm white strings all year. The after xmas stuff is also great, you get some nice colored ones for signals and signs and stuff.


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## Dick413 (Jan 7, 2008)

Go to your airwire manual for that decoder it will tell you what resister to use and how to hook it up to that board
dick


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## bdp3wsy (Mar 14, 2008)

Does anyone have a wire diagram to use the CL's with LED's???


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## krs (Feb 29, 2008)

bdp3wsy said:


> Does anyone have a wire diagram to use the CL's with LED's???


 Check the data sheet - the middle lead is not connected
https://www.mouser.com/datasheet/2/268/20005448A-1021782.pdf


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## Dan Pierce (Jan 2, 2008)

Be sure to tie them to dc voltage in series with the led/leds.
I wire 3 leds in series to the CL2-N2 (some engines have 3 headlights). Also, these are digital and have V+ at 24 volts so I could have 6 in series if needed.


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## Dick Friedman (Aug 19, 2008)

I have stopped using resistors too. The CL2 limits current, and work for anywhere from one to a dozen LEDs in parallel. Yes, they cost more than resistors, but for me, the ability to use them anywhere for any number of LEDs make them much more useful.


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## gizmorama (Jul 13, 2020)

*Installing LED Headlights*

What LED do you favor for headlight use?
And for battery power you would hook up the CL2 in front of the ESC, so that there would be constant VDC & Polarity to the lighting, right?

WES

NW AZ


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## Greg Elmassian (Jan 3, 2008)

There's millions of different leds, normally pick a "warm white" for a diesel, and a yellower one... they are cheap, buy a few and see if you like them.


The CL2 should only have the LED on it, you seem to be asking to power the entire esc...


The CL2 sets a constant CURRENT, not voltage.


Greg


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## gizmorama (Jul 13, 2020)

Hmmm? I imagined the CL2 in parallel with the ESC input so it would always have the same polarity and supply voltage.


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## Dan Pierce (Jan 2, 2008)

The CL2 is a 20 milli-amp limiter and you need to be careful to not use a single 10ma led.
I used 2 10 ma identical leds in parallel with a cl2 with no problem. Also as I am DCC i sometimes put 20ma leds in series. This can make for simple wiring.


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