<VV> Re: LED taillights

[JVHRoberts at aol.com]

You're right, two diodes are needed. Never had them on my boat taillights,  
but it's a good idea. 
So, two diodes, one as described below, and one in  series with the taillight 
wire, with the band or arrow going toward the 50 ohm  resistor. 
 
In a message dated 1/30/2006 1:46:45 P.M. Eastern Standard Time,  
vairmike at sbcglobal.net writes:

There  really should be another diode on the tail light side to prevent 
back  driving the light circuit.

Mike Kost

JVHRoberts at aol.com  wrote:

>Since I have been getting MANY requests for this, here goes:  
>By the  way, my boat taillights have these in them, and this is  exactly how 
I 
>wired  them. 
>
>Crap, I can't find the  drawing, but with four components, it's easy  enough 
>to describe.  
>You need:
>1- Luxeon 3 watt Star, either red or red orange.  Don't get the Luxeon  
>emitter, they are far too troublesome to  heat sink properly. 
>1- Diode, 3 amp, 50 volt. Radio Shack has these.  
>1- Resistor, 10 watt, 10 ohm
>1- Resistor, 10 watt, 50  ohm
> 
>Connect the 10 ohm resistor to the negative end of the  LED, and the other  
>end become ground.
>Connect the 50 ohm  resistor to the positive end of the LED, and connect  
the 
>other  end to the taillight wire.
>Connect the end of the diode with the band  to the positive end of the LED  
>(pointing toward the + end of the  LED), and the other end to the brake/turn 
 
>wire. 
>That's  it! 
>The LED will not draw it's max rated current of 1400 mA (yes,  these run  at 
>over 1 amp!) but 1100 mA when you hit the brakes,  and about 200 mA when the 
 
>taillights are on, and  the diode  will bypass the taillight resistor when  
you 
>hit the brakes!  
>Well, almost. You'll need to find a flasher that'll work properly on  the  
>lower current. They're out there, and are used on the cheesy  LED brake 
lights.  
>
>You can also use an amber Luxeon, and  do the same thing with your front  
>lights! The Luxeon part  numbers are:
>
>LXHL-LD3C Red. These have the intense red light we  all see on LED  
>taillights. 
>LXHL-LH3C Red Orange. These  are a little brighter, and actually have a  
color 
>closer to the  stock taillight color. 
>Either of these will look about the same  brightness through either a red or 
 
>clear lens. 
>  
>NOTE! These are eye stabbingly bright. Do NOT look into the beam  of  the 
LED 
>directly for any length of time. They are fine with a  lens in front of  
them, 
>but a naked Luxeon is a SERIOUSLY intense  light source. 
> 
>LXHL-LL3C Amber. If you're interested in doing  your front lights as well.  
>The output is truly amber, and it'll  shine through either a clear or amber 
lens  
>with about the same  intensity. 
>
> 
>See the Luxeon link to choose what you  want. They also do ordering  online. 
>One other word of caution:  The back plate of these LEDs is NOT  
electrically 
>insulated. As  such, make SURE it is electrically insulated from  the body. 
Also,  
>these make a bit of heat, so mount them on a  piece of aluminum  with epoxy, 
>and mount the bracket on insulated  spacers. These  work best when the LED 
is 
>placed behind the lens in   approximately the same position as the filaments 
in 
>the stock bulbs.  
>
>Have fun!