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LED Headlites for straight DC General discussion
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New member 7 posts oldconductor New member 7 posts
oldconductor

Over the years I have equipped many of my diesels with constant lighting kits.....my layout is straight DC......some 0f the 1.5 bulbs have burned out....since I will have to disassemble engines to replace bulbs, I've been wondering what it would take to change to LED lighting....Any comments...Thanks...Larry

larry mennie
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jrbernier Regular poster 245 posts
jrbernier

Try These

  I have been using LED lighting packages from Evan Designs - They can be used for AC/DC/DCC and any voltage from 7-19 volts.... http://www.modeltrainsoftware.com/bl-212.html

Jim

Modeling The Milwaukee Road in SW Wisconsin
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PAPat Regular poster 283 posts
PAPat

I second the recommendation...

I second Jim's Evan Design recommendation, Larry.  If you are careful in your ordering, you can find LEDs that already have the resister in-line on the LED wire lead and save a step.

 

-bill
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Bruce Petrarca Frequent poster 920 posts
Bruce Petrarca

Litchfield Station has . . .

warm white LEDs with built in resistors: http://www.litchfieldstation.com/xcart/product.php?productid=999007563 They fire about 4 volts and can stand well over 12 volts. If you wire them directly in parallel with the motor with opposite polarity, one will light going forward and the other going backward. The only thing left is to put the correct LED into the correct end of the loco.

Bruce Petrarca, Mr. DCC; MMR #574
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LDBennett Active Member 77 posts
LDBennett

Larry: LED's are polarized.

Larry:

LED's are polarized. That is, they conduct current in only one direction for illumination. Connect them backwards and they won't illuminate. The backwards connection is a problem with a LED across the track DC voltage as it reverses to change the direction of the train.

LED's are raw devices and require some way to control the current... a series resistor. Some have the resistor built in but most do not. If you apply voltage to the LED without current limiting resistance it will burn out instantly. (I verified this just yesterday when making a digital inertia throttle for use on a DC layout. I inadvertently connect an LED directly to 5 volts and it went "poof" with a flash of light and that's it for its life as an LED).

Most LED's will illuminate when the current through them is adequate to produce about 2 to 3 volts across them. Any voltage in excess of that will have to dissipate across the series resistance.

This info is based on the physics of LED's but there are variation of the way they are implemented (some have the resistor built in). The point... don't just buy any old LED and expect it to work. Understand that the voltage and current ratings must be observed as well as the polarity. Model train LED's may contain the required current control but you don't know that unless you investigate the specs.

 

Hope this helps.

LDBennett
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gmcrail Active Member 47 posts
gmcrail

Here's a really slick solution...

This circuit is very compact and reliable.  It requires no additional components, and is quite inexpensive.  I've used it in several locos, and I've had zero problems:

http://www.pollensoftware.com/railroad/circuit.html

Gary M. Collins

http://fhn.site90.net
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