The Asian suppliers have them on the bay in amber and warm white.

About 10 days to get them.

Here's a thousand...

http://www.ebay.com/itm/1000pc...;hash=item540b7c6a03

And, perhaps you don't need a thousand of them!

50pcs 3mm 2pin Round top Warm white Super-Bright Lamp Light LED

I normally buy my LED's in 100-200 piece lots.  I keep both flat and round ones in 3mm and 5mm in stock for upgrades.

Are these for passenger car interiors as per your other Electrical thread?  If so, 3mm LEDs are also available in "flat top" which spreads the lighting more. If using ebay add "flat top" to the search.  About same price as "round top".  Round top shoots a narrower beam, suitable for say headlights.  Sort of like the difference between flood lightbulbs vs. spot lightbulbs in home lighting.  In a pinch you can also sand down the surface (lens) of a round top 3mm LED to diffuse the beam.  Here's a recycled photo from another thread showing the 2 types.

Another trick I do with LED's is to rough up the surface to defuse the light, it works really well for stuff like cab lights and number boards where you want defused lighting.

Back in the day - when golden or warm-white LEDs were at a premium - we would sand the surface of white LEDs and add a coating of clear orange/yellow/golden paint to soften the color.  In addition to diffusing the light (for passenger car interiors) sanding helped the paint stick to the lens. I dug up this photo from almost 10 years ago!

I remember painting LED's somehow I never got exactly what I was looking for, but I guess the fun was in the journey.

Dear Stan

Thank you and everyone else for replying to me on this tread. This question is in regards to changing one led as a head light or running light. The passenger car led strip I got the instruction down pat with no problems. My youngest son has his own train set and I am just trying to repair some head lights that do not work. Instead of using regular screw bulbs I wanted to use LED. Time to order the parts and warm up the soldering iron and hopeful not burn my figures. I have half a clue to what I am doing so this make me very dangerous. I might not be as electrical engineer but I find the people here are very knowledgeable and helpful.  You might find LT. Combo coming out once every now and then asking "One more question".

Thanks to very one who replied. I would like just point one that you really helping out a lot more people than you think you are. I have followed a lot of these question and answer forms for years and found them very help years after the original question was answered. And have used these solutions without asking any questions because they answered so well.

Thanks again

Kris

I have some Bi level cars that have 3 or 4 grain of wheat bulbs plugged into connectors along the roof. And one bulb over the lower level. I'm thinking that I could plug in some warm flat top LEDs where the bulbs were plugged in and power them with a GRJ rectifier/regulator module. Saving redoing the bulb strip under the roof. The LEDs are 10000 mcd and 120 degrees spread which converts to about 32 lumens. I wonder if just 3 or 4 of these LEDs will be bright enough. Anybody do this...?

If you don't alter the existing bulb strip, doesn't this mean you are connecting the LEDs in "parallel" with all LEDs presented the same ~3V DC.  At 20 mA per LED to reach the stated brightness, that's 80 mA for 4 LEDs.  GRJ will chime in but I believe that's beyond the operating range for his module.

32 lumens for a single "standard" 3mm LED seems quite high to me but let's take that at face value.  What would 4 LEDs x 32 = 128 lumens look like in a passenger car?  Small incandescent bulbs as used in our passenger cars might put out, say, 5 lumens per Watt.  So it would take 25 Watts of incandescence to generate 128 lumens.  Many passenger cars would melt with 25 Watts going in.  I'd say 128 lumens would be more than enough!

That does sound like more than enough light. The boards are capable for 45 ma, so if I just use one board, I would set it for about 40 ma and would have adequate light. I guess I'll have to try it.

As to the lumens, I didn't do the math, I just found a calculator like this one when I was refreshing my understanding of lighting units...

http://www.rapidtables.com/cal...lumen-calculator.htm

Most of the 5mm LEDs available seem to spec 10000 to 15000 mcd. Not sure what they really are...maybe.

The other issue is that the LEDs have kind of rectangular pins and I wanted to see if I could just plug them in to the sockets Lionel is using for the tiny grain of wheat bulbs.

FWIW, when I use the LED strips, I end up using 15-20ma for the entire 18" car.  That's 24 LED's powered in 8 groups of three at 12 volts.  Each LED has a current of around 2.5ma, and the lights in the car are plenty bright.  I've had several people already contact me with my lighting modules and ask how they tone down the lighting at the lowest setting, that is about 5ma light output, and they want less!

I prefer the even lighting of the strip along the whole length of the car in any case.  I did a bi-level car for someone, and I just continued the wiring to the second strip of lights.  One of the major pluses of using the LED strips is the even distribution of lighting.

That may be the best way...just replacing the Lionel strip with the LED strip. The tiny incandescent bulbs seem to light evenly, but that's probably not how the LEDs spread light. I figured on the flat top ones, but it's beginning to sound like the strip is best.

Chuck, one thing to keep in mind.  If you are using the constant current capability of my board and running the lights all in parallel, you are putting a lot of power out as heat in the module.  Take  that 40ma at 3V with a track voltage of 18 volts.  After the full-wave rectifier and filter, you have around 25 volts of DC.  That results in close to 1 watt of power being dissipated in the regulator, so it's going to get pretty warm.  If you run the lights in series, you end up dissipating less than half of that as a rule, much easier to deal with.  You may have to add a heatsink to the TO220 package for your application.

I really designed this with the 12V strips in mind for command use, it works well in that application.

Edit:  I see you slipped in there, I believe I agree, use the strips, you'll be very happy with the result IMO.

It is millicandelas. Conversion tool LED mcd to lumens

Yes thanks, good point on the regulator power dissipation.

At 2.5mA, LED voltage is ~2.9V.  So total LED power is a miserly 0.2 Watts (24 x 2.9V x 2.5mA).  Strip LEDs are probably ~50 Lumens per Watt (about 10x that of a grain-of-wheat incandescent) so that's 10 Lumens for the entire passenger car.  Now that seems more like it!

As GRJ says, the uniformity of lighting is a key benefit of the strips.  I'd also think the vertical height in a bi-level is reduced so it's best for the LEDs to be as short/thin as possible and as close to the ceiling as possible to let the beam spread out.  Here's a recycled photo from another thread showing the height difference between 3mm LEDs and a strip LED.  Obviously a 5mm LED would be even taller.   

If for whatever reason you really want to stay with the existing bulb strip it seems the manufacturers continue to come out with new 2-pin white LEDs that replace standard incandescent bulbs.  They generally have several surface-mount LEDs crammed into some geometry to provide the uniform all-around lighting expected from bulbs.  While I don't imagine anyone else trying this, here's a DIY example of taking 4 LEDs from a strip to make a replacement for the incandescent bulb in a lock-on.  Photo recycled from another thread...