g741.org

Well put!

about the LEDS, they dont really "Care" what voltage you input, so long as it matches what they use. Any more, they will burn out, any less, they wont light. For example, white LEDS draw 20mA @ 3.3V, so this gives them an internal resistance of 165 ohms. Now, to run those on 24V, you would need a 1W 1200 ohm resistor. However, if you wire them in SERIES, they will naturally drop the voltage 3.3V per LED. this means you could run 7-8 LEDs in series and be ok, with no need for a resistor.

LED output is not voltage dependent. Voltage merely controls wether they will light, not light, or burn out. too low, no light, too high, they burn out fast.


What you want is a high output LED. LED output is measures in mCD, milicandelas. Obviously, higher is better.

Two VERY important advantages of LEDS over lightbulbs are this:

VERY long life, and much less current draw. Most LEDS dra 20mA each. So, lets say you use 8 LEDS for a turn, and 8 LEDS for a stop circuit, X2 for a pair of lights. This would be 32 LEDs, @20mA each. This is a total current draw of .64 AMPS!!! A single circuit light bulb on its own draws 2-3 times that, easily! On these old trucks, with delicate(read: weak) electrical output systems, the LEDS remove alot of load from the system.

One more important thing about LEDS is that they have a very narrow illumination angle. You can buy special wide angle LEDS, however.

I just put these in the headlights of my Audi. They make good daytime running lights, and the blink with the blinkers. They are VERY noticable from across an intersection:

I never considered LEDs for the plug in rig I am dreaming up. Can you make them blink with a regular relay or is their some solid state circut you can wire in between the power supply and the LED?

Well this thread is surerly full of good ideas. I still have the M35 mud flap reflectors for night driving Rick Larsen sold me. I shall hang them from the rear on each side and I hope they will be noticeable.

I build retrofit LED's into lots of projects.
LED's WILL get considerably brighter as they approach the point of thermal runaway.
20 mA and 3.3V is a good place to start, but if you can put them on a variable power supply, increase the voltage to the point where the current draw starts to climb, then back the voltage off till the current stabilizes.
Then you are at the constant current max ouput for the LED.
Put however many in series you need X the stabilized voltage then you're
good.
See:
http://led.linear1.org/led.wiz
And:
http://led.linear1.org/category/led-basics/
And:
http://led.linear1.org/why-do-i-need-a- ... th-an-led/
This will give you a good primer for LED's.
J.B.

jbxx wrote:I build retrofit LED's into lots of projects.
LED's WILL get considerably brighter as they approach the point of thermal runaway.
20 mA and 3.3V is a good place to start, but if you can put them on a variable power supply, increase the voltage to the point where the current draw starts to climb, then back the voltage off till the current stabilizes.
Then you are at the constant current max ouput for the LED.

This is true, but the problem is that you drastically shorten the life of the LED. However, fi you dont mind changing them as frequently as regular incandescent bulbs, then this is a great way to go. I cemented the ones in place on my Audi, so I went VERY conservative on the juice.

Rusty S. wrote:I never considered LEDs for the plug in rig I am dreaming up. Can you make them blink with a regular relay or is their some solid state circut you can wire in between the power supply and the LED?

They will blink with a regular relay. Im sure there is a solid state circuit that will do the same, but I have no idea how such a beast would be made. Google it, I am sure someone out there makes one!

My M37B1 had composite lights when I got it, looked Military and worked well - tail lights and stop lights on both sides that were nice and bright.
Another suggestion is scotchlight reflective stickers, if you look you can find 2" or so circles that are peel and stick, they really add visibility at night. Some dealer used to list mil-surp 'brown' scotchlight tape that was not too noticeable during the day but reflected quite a bit at night.

CD

I made the decision to upgrade my tailamps for my resto. I picked up a set of Humvee tailamps today. I know it is not authentic but I don't want someone to rear end my five year restoration when finished

Here's a site that sells a black that turns white.

http://www.reflectivelyyours.com/generic141.html

Here's someone selling brown by the linear foot.

http://cgi.ebay.com/3M-Reflective-Scotc ... dZViewItem

Well this is my solution for night driving.
This is one of the few modifications I made in my truck. You don't notice anything from the outside. On the inside there are 2 blackout lamp bodies the cable goes though a hole on the floor.
The goal was to find those lamps, originally built for a french AMX13 Light Tank. They are basically the same as the US blackout lamps but exactly the diameter of the cat's-eye. Inside there's place for three lamps rubber mounted stop, turn and driving.. I really beat many many times this tailgate never get a burnt lamp in years.
Between the cat's eye and the lamp I installed a red glass to get a deep red light.
Also these french lamps are small enough to let the troop sets to work with no intersections.
Maybe is a large modification but is the only way I found to drive securely and still looking original.

well, i did some fancy rewiring on my duece, when i have to have it on the road at night, i rigged it so my breaklights are on all the time,
when im on the turnpike or on that super highway, all i have to do is flip a switch, and ive got break lights again.
kevin