Installing LED in Loco's

S

Simon Potter

Srpott40
Just wondering if anybody has replaced the old fashioned bulbs on some of the older LGB engines with LED's. Over the next week of so i plan to install a DCC chip into my recently acquired Stainz loco (20201). I plan for this loco to be the backbone of my operations this year. I often do a bit of late night running, and so a bright front light is vital, and although the current bulbs are ok i was hoping for something a bit brighter!

On a more technical note, i understand that you can run LED's at different brightness by adjusting the voltage going through them, has anybody managed to program a Massoth chip, so that say i could either have the LED either off, dim (for daytime running), or fully on (for nighttime running)? If so could you let me know how you achieved this

Thanks in advance for your help
 
LED's are current fed devices, but it is a difference you don't really need to know about..
To get different brightnesses, you use two outputs from your decoder, each with a different value current limiting resistor.
You set the outputs to be controlled by the light control key, possibly direction the loco is travelling in, and a F-key for the 'brighter' setting. You can then control the brightness, as well as on and off.
 
PhilP said:
LED's are current fed devices, but it is a difference you don't really need to know about..
To get different brightnesses, you use two outputs from your decoder, each with a different value current limiting resistor.
You set the outputs to be controlled by the light control key, possibly direction the loco is travelling in, and a F-key for the 'brighter' setting. You can then control the brightness, as well as on and off.
Click to expand...
Thanks what would happen if I accidentally had both the outputs turned to on?
 
Use a 1k resistor soldered on one leg of the led don't worry about the maths the led will work on way round and not the other you wont blow anything. if you want to control the brightness use the CV value.
 
If you had one resistor running the led at max current, then a second one in parallel could destroy the LED, it depends on the second value.

Not a good way, use the brightness control in the decoder if you have it.

And LEDs work on current not voltage, the reverse of how lamps work. You need a resistor properly calculated. 1k ohm is often ok, but I prefer to calculate.

A little help here:

http://www.elmassian.com/index.php?option=com_content&view=article&id=636&Itemid=844

Greg
 
In all my old LGB locos Stainz, 2076 Tank Engine and 20231.8 short engine I just wired the the LED's across the motor lugs.
I wired them in opposite polarity so when going FWD the front one came on and the rear when going in REV.
The current draw in the is not significant when compared to what the motor is drawing that this does not cause an issue.
I personally don't muck around with dimming as most small/field type loco I have seen have the light either on or off. My lights can hardly be seem in bright sunshine and at night they light up the rails for about a metre ahead and shines on lineside buildings so they look realistic to me.
If you do need to vary the light level consider 2 leds side by side and turning on or off.

This calculator may be of some use for resistor calculation.

http://www.hobby-hour.com/electronics/ledcalc.php
 
I was trying to keep it simple for the OP..

Simon, use 1K resistors on both outputs. The idea is to have just one output on when low-level light is required, and BOTH on for the higher-level..
Once you get to doing this, come back to this thread, let us know what Central Station etc. you have, and we can take it from there.

(A blatant plug, but if you wanted pre-wired LED's, then look at www.rctrains.co.uk - A note saying what you wanted to do, and I could pre-wire the resistors for you.)
PhilP.
 
See attached picture, modify it to suit your particular installation.

For the resistor calculations the following will be required, voltage output from Function Output ((leave Function Outputs to default ie 32)) (turn function ON, connect NEG lead of multimeter to Function Output, and POS lead to +22), forward voltage and Ma rating of each type of LED you intend to use. Good practice is to attach the resistor to the NEG leg of the LED, which is the connected to the NEG of the Function Output, use the +22 as a "ring main" to connect all the POS legs of the LED's to it.

Lights.png
 
Keep it simple - wire your new LEDs direct to the lighting outputs on the decoder and drop the value of CV50 (for massoth) to about 7 or 8.
OK, so you don't have brightness control, but its simple, robust and IT WORKS.
 
Uhh.... Arthur, you have some resistors labelled 100k ... that cannot be, right?

There's 2 leds in series... 22volts minus about 7 volts for the leds is 15 volts.

V = IR ... so 15 = 100k times current... so that would yield 0.15 milliamps .... normally even the most efficient LEDs need 5-6 millamps.

Most bright leds need 20 milliamps.

Greg
 
Ralphmp said:
You may also want to look at LED "bulbs"; e.g. on ebay here:

http://www.ebay.co.uk/itm/S079-5-Pc...lso-Marklin-/252741626511?hash=item3ad8932a8f

Using on of these only requires you to replace the current two-pronged socket with a suitable alternative and then fit the bulb. Appreciate they aren't cheap in comparison to buying an LED and a capacitor, but it could save you some installation effort.
Click to expand...

On the U.S. ebay it looks like the same led lamps come from Germany.
http://www.ebay.com/itm/S079-5-Pcs-...hash=item3ad8932a8f:m:ms2B10Z8Q2PoMbjv1HIu43w
I wonder why nobody imports them here?
 
I use the E5.5 led bulbs in the Pola/Piko lamp holders in place of the tungsten originals.
I get them in bulk at under £14 for 10.
They are perfect for that use and for use in other E5.5 bulb holders for buildings etc.
Yes they are more costly than wiring up your own system (which I will also do if needed), but they are mighty convenient for me as I have a lot of the Pola/Piko lamp holders (with modified to smaller size reflectors) on the outside of buildings.
An example here:
snow night time at quarry.jpg
 
I used LED's on my Piko Kamel and 218 Chipping jobs. Set the correct voltage from the Massoth chip but used Diodes to ensure that no problems of cooking the LED's if I got the polarity wrong. Always a worth while belt and braces job. Using veroboard with short lengths of Brass Tube soldererd in, the LED's are just a push fit. Easy for replacements.
JonD
 
I have replaced them in a very old Schoema as the original old style small headlight housing would deform with 18 v 5.5 bulb heat. I bought some ready made directional 5mm warm white LEDs from Evan Design, here in Denver, and, simply wired direct to old light wires. Bent the leads so it sits at 90 degrees, and the light is very good just with the LED alone. Far better beam than the old bulb, even at high voltage. And bright during daylight, so it looks more prototypical

Ditto with an old 2090?? "little Lisa" (the side rod diesel from olden day, in yellow) these came sans working lights originally, with small housings and milk white lenses , and, built in red lensed housings on the rear cab wall. With a bit of drilling, LIghted only the lamp on top of the radiator, and a single red rear lamp, sort of RhB style, and again, the larger 5mm LEDs are very bright, cast a strong focused beam, simply using the LED without any additional lens or reflector. This one was a cool white, very intense and modern looking. At night they seem to throw much further and brilliantly than the warm white equivalent.

I did this too with the last Elias version, adding an oversized staniz lamp and warm LED to the unlighted end of the loco, high, abovoe and in between the windows. This LEd sits well in the new Stanz rear lamp housing and white refelctor assembly and casts a great beam, and, works nicely when the loco is moving slowly.

Did LEDs too on two LGB rail trucks, using chips in the truck headlight, drilling through to allow for wires.

FWIW Evans can make anything, any size , 1mm, 3mm, 5mm, chips, red to white in 3mm, DC, DCC, directional, any color , and any voltage, from coin cell to n/ho scale voltages to garden voltageand at the time i bought mine a few years back were about 3.50 each.

I have used some in buildings, like Susch station, where i put an UV (light purple light but indeed UV) in a brass tube for a theatre can light affect, in order to shoot a beam from under the eaves onto a platform clock face, to simulate backlit flourescent lighting.

The beauty of these LEDs, if you dont need off on , is to wire directly to track voltage.
 
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