Nice work Jerry!
Rich
Jerry,. WOW!!!!!
That is beautiful work.
When I do these conversions I don't use a diode, I use a full wave rectifier, it's very small also less than 1/4 the size of the converter and rated at 1 amp, plenty for the strip of LEDs , the rectifier will allow you to reverse the polarity with no loss of the lighting. The strips are made for 12 v DC and with the converter you can adjust them for the brightness you desire they, the strips, also come in a variety of colors.
Ray
Rayin"S" posted:Jerry,. WOW!!!!!
That is beautiful work.
When I do these conversions I don't use a diode, I use a full wave rectifier, it's very small also less than 1/4 the size of the converter and rated at 1 amp, plenty for the strip of LEDs , the rectifier will allow you to reverse the polarity with no loss of the lighting. The strips are made for 12 v DC and with the converter you can adjust them for the brightness you desire they, the strips, also come in a variety of colors.
Ray
Thanks for the compliment. There's a LOT of work in these cars. Five of them are standard coaches, and one is a "smoking" car with a special section for smokers. All of the interiors are three shades of blue, so LEDs look more blue than they are in actual life. I'll tint the ones I have with some clear orange to soften them up a bit. Lowering the brightness will help too. BTW, I ordered those buck converters and will report on how they perform. Here's hoping...
As to the diodes, I use full wave rectifiers too, but all they are is a few diodes. And I've had one in the bridge fry on two occasions. That's why I am hesitant to install one in the roof. So I usually isolate the rectifier somehow so if it does fry, no plastic is nearby.
Hey guys, Happy New Year! Hope your Christmas time was a great one.
Jerry as always, your work is outstanding. It’s the kind of modelling I would like to be doing but know I will never get to it. Just curious, when you said you ordered the buck boosters are you talking about the mini’s Ray posted?
And I should have memtioned, the Brunswick green Flyer K5 in my Xmas videos was done by Jerry. Like all his work, it is beautiful and thanks again.
Happy New Year (I hope) to all,
Tom Stoltz
in freezing rain Maine
Tom Stoltz posted:Jerry as always, your work is outstanding. It’s the kind of modelling I would like to be doing but know I will never get to it. Just curious, when you said you ordered the buck boosters are you talking about the mini’s Ray posted?
And I should have memtioned, the Brunswick green Flyer K5 in my Xmas videos was done by Jerry. Like all his work, it is beautiful and thanks again.
Happy New Year (I hope) to all,
Tom Stoltz
in freezing rain Maine
Hi Tom,
Thanks for the compliment. Yes, the buck boosters are the ones Ray suggested. For the price, you can't beat it, and you know I'm cheap. I'll let the list know how they turn out in my application. If Ray suggested them, they're going to be good.
Happy New Year to you and Nancy, my friend!
Jerry
A little over a week ago, I ordered the mini regulators that Ray suggested. They came in 5 days! I ginned up a temporary circuit to test them out. Just what I was looking for! The module measures 17x11x3.8mm. I also got a few full wave bridge rectifiers and some 470μF 50volt caps for the circuit. I assembled it with a slew of alligator clips, and it works great. The caps smooth out the voltage to the LED strip to light the LEDs better. I have them adjusted to around 9VDC and they look great. With the size of the regulators, rectifiers and caps, they could be hidden in the S scale bathrooms! The rectifier and regulator on one side and the cap on the other. I'll power the circuit for a few hours on the bench before I stuff it all in the cars, just to be on the safe side. I want to see if it generates a lot of heat, or if a component will fry. When I finally install the circuitry, I'll post a photo or two.
Here's a shot from the bottom of the shell of what kind of room I have in the bathrooms. Just enough for the caps and other circuitry, The bulkhead with the bathrooms slides in the shell along channels on the shell, and is removable. The circuitry will be installed, then the bulkhead slid into place:
The small squares are drilled and tapped to screw the floor/chassis in place. A two pin mini connector will allow shell removal if necessary.
Thanks again, guys, for the suggestions!
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Jerry, Good to see that you can hide the components in the bathroom
Ray
Ray and Jerry -- the link to the eBay converter provided by Ray earlier goes to this label: "JacobsParts Mini360 DC Voltage Step Down Power Converter Buck Module" -- based on both the title and the specs in the listing, this is a buck module only, not a buck-boost module. So if you are running Legacy or TMCC (?), etc. at a fixed AC track power (usually something like ~18 V), then a buck module should be all that is needed. So this device would work, as would the device that GRJ devised - which has the added advantage that it does the AC-DC conversion on the same board (widely discussion on other OGR fora).
However, if one is running conventional variable AC, then a buck (only) converter might work if the LED strip lights work at something like 4 VDC, since the track voltage is - for most practical purposes - going to vary between ~4 VAC and ~16-18 VAC. In this case, a buck converter will operate 'correctly' and simply step the voltage down to a user-set constant output voltage (that is always lower than the supply voltage). But if one uses the common LED strip lights that are spec'd at 12 VDC ( and perhaps operated around 9 or 10 volts to control the brightness) with variable AC track power as input to the buck converter, there will be times when the supply voltage is less than the output voltage set point for the buck converter; in that case the buck converter output goes to zero (or near that).
A search for buck-boost converters on eBay will yield a lot of (mostly Chinese) buck boost boards that I'm sure would work - though I haven't seen any that are very small, which is one of Jerry's requirement for his coaches. My assumption is that a lot of the buck and buck - boost boards that operate in the ~1 to ~20 VDC range and seem to be widely available on eBay and Amazon are designed for automotive systems. I wonder if these are 'over-spec'd' compared to what the requirements are for a board used to control voltage to an LED strip for lighting model railroad passenger cars. I'm not enough of an electrical engineer to know that - but perhaps there are circuit diagrams, etc. for a buck-boost system that meets the needs of the model railroad community - including small size.
- Rich
ps Jerry - the car interiors look fantastic -- the couple of close-up shots you posted are indistinguishable from the "real thing".
Now that I've completely hijacked this thread (
) I'll show what the results of my testing on the buck modules produced. I bench powered the circuit for HOURS and no heat. So here are the components installed. The pencil marks show where the drop-in vestibule goes and how much room I have. The bare wires from the rectifier are where I'll solder on a two-pin connector about 4" in length so I can remove the shell from the frame if necessary. The second photo is with the vestibule in place, and hiding the circuitry. The LEDs start at about 6V and stay fairly consistent up until 9V where they reach maximum brightness:
Admittedly, a buck booster would be ideal, but this is a good enough substitute.
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poniaj posted:Now that I've completely hijacked this thread (
Admittedly, a buck booster would be ideal, but this is a good enough substitute.
Jerry, as always, superb work. I am in awe of the modeling you do. And I’m very interested in this whole buck-boost thing, but still confused about what it is. I looked them up in Wikipedia and was left in a daze. I sort of though the buck was a voltage regulator while the boost is like a voltage amplifier.
Why I’m interested is I run DC and I run the trains slow. That leaves almost no lighting in the passenger cars. So this looks like a simple way to brighter, constant lighting. However, I get the feeling that the buck you used – without the boost – does not have constant lighting… if I want constant lighting I would need to use the one that includes the boost – is that true?
If I made this modification to the lighting, what impact would there be if I went to DCC in the future? My main reason to consider DCC is to get sound (I can’t hear the choo-choo anymore – even with hearing aids) and lighting… Probably asking for too much.
Tom
Tom, the buck booster will not give you constant lighting, to get that you would need either a control system that keeps power on the track or install battery in the car. If you are concerned about the flickering while running l added a 1000 mfd capacitor to the circuit.
Ray
Ray -- I'm missing something in your response to Tom...? Doesn't a buck-boost system provide constant voltage (usually an adjustable set-point on the output voltage) - so it should provide constant light levels - or something close to it, should it not?? It won't if the track isn't powered, but I don't think that was what he was asking(?).
Tom - The boards I have seen on Amazon or eBay are typically DC in to DC out, so at least in your case, you won't need to use a bridge to convert AC to DC. A cap across the input would help with any flickering.
richs09 posted:Ray -- I'm missing something in your response to Tom...? Doesn't a buck-boost system provide constant voltage (usually an adjustable set-point on the output voltage) - so it should provide constant light levels - or something close to it, should it not?? It won't if the track isn't powered, but I don't think that was what he was asking(?).
Tom - The boards I have seen on Amazon or eBay are typically DC in to DC out, so at least in your case, you won't need to use a bridge to convert AC to DC. A cap across the input would help with any flickering.
I probably used the wrong term, maybe I should have said consistent, brighter lighting. What I’m experiencing is that running the trains at such low voltage there is virtually no light in the passenger cars. What I was getting from this thread is the buck and buck-boost appear to increase the voltage available to the cars and the LED requires less voltage to begin with. Or so I thought.
Jerry is using a buck without the boost – what does that mean for the lighting? I’m also curious about going to DCC in the future. What impact would that have on a buck-boost system?
Tom
Tom - first, a disclaimer - I know, in general, how these work and I've spent some time trying to figure out the best way for me to retrofit my AF passenger cars and cabeese with LED lights and a circuit to provide both constant (and hopefully flicker-free) lighting levels - all while running with conventional variable AC track power. However, I haven't actually done anything yet !! - so you can size the grain of salt with which to take the following (hopefully it won't be too big...).
As the names imply, a 'buck' converter steps the DC input voltage down to whatever fixed output level you choose - even though the input voltage may vary. For our purposes, these are typically in the range of several to maybe ~18 - 20 V on the input side. The output side - assuming you are driving an LED strip light or string - is typically 12v (DC), although some of the folks here report reducing the voltage to ~10 v to reduce the brightness. The main point here is that for a buck converter, the input voltage ALWAYS has to be higher than the output voltage. So if the output voltage is ~10 to 12 V, the track voltage needs to be higher than that - which I suspect is much higher than what you run. I'm not sure what happens when the input voltage is less than the output voltage on one of these boards - I assume it simply stops working and the output goes to zero.
For a 'boost' converter, the opposite happens - namely the converter steps the DC input voltage up and the user-selected output voltage is ALWAYS higher than the input voltage. Again, the input voltage can be variable, while the output voltage is constant. This type of converter is likely to be the most useful for your situation - namely low track voltage for running the trains but still wanting to have ~10-12 VDC for lighting. HOWEVER, in the event where the track voltage goes higher than output voltage set to ~10 to 12 VDC, then I'm not sure what happens - either the converter stops working and the output voltage goes to zero or it stops working and the output voltage goes up with the input voltage, which could damage the LEDs.
So a 'buck-boost' converter is the merger of these two into one board. So the track voltage can now vary between zero and - say - 18 VDC and the board will provide a constant voltage output (e.g., ~10 to 12 VDC to light an LED strip). Here is a somewhat lame, but the best I could find quickly, YouTube presentation on these three types of converters. I don't know why these guys (and they are almost always guys) all have British (or maybe Aussie?) accents and speech mannerisms, but... if you can get past the tedious points, it illustrates what I've tried to describe above: https://www.youtube.com/watch?v=9--_jaxiXhE. If you want to cut to the chase right away, the buck-boost discussion starts around 11 minutes in.
One other consideration - you don't say (as I recall) whether you use (or plan to use) LED lighting or whether its incandescent. If the latter, you might be able to get away with only a boost converter with the output set at a voltage you are likely never to exceed on the track (like 16-18 VDC). The incandescent bulbs can handle those higher voltages, although if its too high, then the lights may be brighter than you want and then you are back into 'buck-boost' territory. The issue, as discussed in the youTube presentation, will then be how much current and wattage the boost or buck-boost converter will need to supply for the incandescent bulb. My thinking has always been to convert to LED lights - much lower current draw and more uniform lighting along the length of the car, etc. So then its "just" a matter of finding the right buck-boost board that is small enough to fit inside the car. Unlike Jerry and others - who've detailed out the car interiors (spectacularly) - I'm staying with the old paper diffuser look, so I don't have a "hide the board" problem.
Tom,
Rich has it correct, as far as I can determine. I am using the buck module as a voltage regulator. I have it set at 9V to keep the LEDs from being too bright. They start illuminating around 5-6V and rapidly go to full brightness with the cap I have in the circuit. Granted, I too would like them to illuminate at a lower voltage, but I can't fit all the electronics of a buck booster in my NH cars. So what i have till do. I will be pulling them either with an AC Flyonel EP-5 (which runs on at least 5V) or a pair of DC powered DL-109s. In the later case, the train will have to be going fairly fast to allow the LEDs to illuminate. I may install a resistor in the circuit on the locomotives just to allow more light in the cars, but that's a while away. IN any case, the buck module will also allow me to use them on a layout with DCC or even FlyerChief, both of which give a lot more voltage to the track while some sort of decoder drops and powers the locomotive at a variable speed. At least that's the plan...
Tom,
One thought for you, running DC power, you mentioned you run at low speed. Might you consider using LEDs ? The strip LEDs that most of us use are set to operate at 12 volts, you might assemble your own LED lighting using individual LEDs with a buck converter adjusted to limit the output to around 3 volts. I would still use the rectifier in the circuit, if you do reverse the polarity the cars will light in both directions.
Ray
Ray - you make an interesting point - if one is running DC and then reverses the polarity to back up, what happens to the lighting and more specifically the converter board? The boards have definite positive and negative inputs so I suppose reversing the polarity risks frying the circuitry? You suggest that using a bridge rectifier feeding the circuit - even though the track power is DC so no AC to DC rectification is needed - will still maintain the right polarity feeding the lighting board even when the input polarity is switched. Good idea - I had only thought about rectification in the context of AC to DC conversion.
I covered this point in an earlier post that also has the answers to a number of questions asked in subsequent postings. I think that any modification should consider use on AC, DC, and DCC operating systems in order to make the lighting work no matter on whose track the cars are going to run. The manufacturers take this flexibility into account in their products, and both Lionel and MTH have wisely taken this approach in the more recent locomotives, too.
- a bridge rectifier to allow the passenger car to run on AC as well as DC. It is necessary to keep the LEDs illuminated when you change DC polarity to reverse an engine. (Without the rectifier, the lights would go out when you back up because reversing changes the positive DC track wheels to negative DC and the negative wheels to positive. The rectifier keeps the output current the same polarity even if the input changes. ) Rectifiers cost about $0.44 each.
TOKELLY posted:I covered this point in an earlier post that also has the answers to a number of questions asked in subsequent postings. I think that any modification should consider use on AC, DC, and DCC operating systems in order to make the lighting work no matter on whose track the cars are going to run. The manufacturers take this flexibility into account in their products, and both Lionel and MTH have wisely taken this approach in the more recent locomotives, too.
- a bridge rectifier to allow the passenger car to run on AC as well as DC. It is necessary to keep the LEDs illuminated when you change DC polarity to reverse an engine. (Without the rectifier, the lights would go out when you back up because reversing changes the positive DC track wheels to negative DC and the negative wheels to positive. The rectifier keeps the output current the same polarity even if the input changes. ) Rectifiers cost about $0.44 each.
I thought Terry did make this clear before. Switching polarity is the main feature of running DC. So unless the buck-boost can handle reversed polarity, a rectifier is a must. My main question was how to think about the buck and boost. Rich, I did try to watch the uTube, but with my hearing and the accent plus my (lack of) knowledge about electronics, made it a real non-starter for me. However, I think my primitive interpretation is actually fairly close; that is think of the buck as a variable voltage regulator and the boost as a voltage amplifier.
Now the voltage amplifier part of this makes me think about throwing one of these at a smoke unit… any thoughts?
Tom
The basic white LED runs at about 3.5 volts. If you eliminate the built-in resistors in what ever LED string you are using, you can put in a voltage regulator and illuminate the LEDs at about 4-5 volts of track power. There is some overhead lost in the regulator.
If the input to the regulator from the track has a bridge rectifier (4 diodes in a bridge) the LEDs will illuminate on AC , DC+ or DC- track power and almost any voltage.
I see that Ray said basically the same thing.
If you run command and have track voltage all the time, these will do it one stop.
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@gunrunnerjohn posted:If you run command and have track voltage all the time, these will do it one stop.
Thanks John, I run DC variable track voltage.
Tom Stoltz
in Maine
Well, you can actually still use the regulator, but you would use the 5V LED strips instead of the 12V LED strips. Unless you truly have a buck/boost regulator, you would not be able to use the 12V LED strips if you run conventional with variable voltage.
Hi Tom, I'll post the values once I get home from work. I also found inexpensive buck-boost converters, and I'll post a link to that Amazon site, too.
Terry
I used 12-volt warm white LED strips because they were the least exspensive and most readily available at the time. That color value looked best in heavyweight coaches anyway. Amtrak coaches might look better with a cool white to represent bright fluorescent lights. The choke is an Epcos/TDK with a value of 22 millihenries that I bought from Mouser for $0.35 each. I don't see that choke on the Mouser website any longer, but there are some that are close to those in terms of price and below half an amp in maximum current.
The bridge rectifier is also from Mouser, an RB153:
https://www.mouser.com/c/?q=RB153
The capacitor is a 35-volt 1000 microfarad piece that didn't perform much better than a 470 mF capacitor. I have found that clean track and wheels make a much better contribution to reducing flickering than the capacitors have.
One source for inexpensive buck-boost converters is:
https://www.amazon.com/XL6009-...B07XG323G8&psc=1
I can't comment on their quality because I have not used them, but I suspect that if they work, it is a good idea to check their output because all the ones I tested with a voltmeter had to be turned down to 7-8 volts to prevent burning out the LED strips before use.
Terry
@TOKELLY posted:One source for inexpensive buck-boost converters is:https://www.amazon.com/XL6009-...B07XG323G8&psc=1
I can't comment on their quality because I have not used them, but I suspect that if they work, it is a good idea to check their output because all the ones I tested with a voltmeter had to be turned down to 7-8 volts to prevent burning out the LED strips before use.
DANGER WILL ROBINSON!
These are only BOOST converters, so if your track voltage goes over the max rating for your LED strips, you have a problem.
Below is a link to a buck/boost supply, note the two inductors. This will keep the output voltage over the entire rated input voltage.
XL6009 DC-DC Step Up Step Down Boost Buck Power Supply
Note the one you specified says: Output Voltage Adjustable Step-up Converter Board Module
Sorry about that! I quickly searched for "buck-boost converter" without reading through the information. The other information is valid. In my own records I had links to all the devices I purchased, but not one link worked today; so I didn't copy any of them. I apologize.
Terry
@TOKELLY posted:Sorry about that! I quickly searched for "buck-boost converter" without reading through the information. The other information is valid. In my own records I had links to all the devices I purchased, but not one link worked today; so I didn't copy any of them. I apologize.
Terry
Thank you Terry & John,
I will look closer at the pricing tomorrow, but it looks like about $7.00 per car… I guess that’s not too bad… though it might be hard to slip by the accountant. Terry, I had no trouble with the LED link to Amazon, 32.8 ft for $17.00 – looks like a good price.
I do have two questions: in the diagram there is something I interpret as a resistor (maybe the red rectangle is the choke?). What should the value be? And is the choke necessary, I don’t recall seeing them in other circuits, plus the Mouser is $3.11 if you buy 10. That’s about half the cost per car.
If the capacitor really doesn’t reduce the flickering, why add it?
As you can tell, I have no idea what each item contributes to the whole system.
Thank you for taking the time to look up the values,
Tom Stoltz
in Maine
Tom,
The cap will reduce the flickering, and if I remember correctly you run conventional rather than command. You might consider using the 5v LED strips, you would need a higher value resistor to protect the strips or use one of the tiny DC regulators, which is my preference, found on the auction sight. Those regulators are what I have used, one per car, at under a buck each,
Ray
@Rayin"S" posted:Tom,
The cap will reduce the flickering, and if I remember correctly you run conventional rather than command. You might consider using the 5v LED strips, you would need a higher value resistor to protect the strips or use one of the tiny DC regulators, which is my preference, found on the auction sight. Those regulators are what I have used, one per car, at under a buck each,
Ray
That’s what I assumed the capacitor would do. On a H0 YouTube, the DCC Guy demonstrates that the cap actually eliminates the flickering. That’s why I was surprised a Terry’s statement about flickering.
I do run filtered, regulated, DC from a 13.8 VDC power supply. GRJ had a link to 5Vstrips in one of his post, however the link went to 12V strips. The ones I’ve been able to find are cool white rather than warm white, I would be concerned the cool white would be too bright. But I am in uncharted territory here so I really have no idea.
And while in uncharted territory, changing the design to use DC regulators with a bigger resistor is beyond my pay scale… I would have no idea. Are you using the 5V LED strips with youir DC regulators?
Still lost,
Tom Stoltz
in Maine
5 meter 5V Warm White LED strip, $6 shipped.
DC 5V USB LED Strips 2835 White Warm White Tira LED Strip
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@gunrunnerjohn posted:5 meter 5V Warm White LED strip, $6 shipped.
DC 5V USB LED Strips 2835 White Warm White Tira LED Strip
Interesting, thanks John. Looks like this strip can be cut in one LED increments. Six bucks for 5 ft.
Tom Stoltz
in Maine
@Tom Stoltz posted:And while in uncharted territory, changing the design to use DC regulators with a bigger resistor is beyond my pay scale… I would have no idea. Are you using the 5V LED strips with youir DC regulators?
My regulator boards are a constant current design, so they regulate current and not voltage. This works out to be more controllable as far as intensity for LED use as LED current vs light is a linear function. However, LED voltage vs light is most certainly not a linear function, it's a very sharp knee from dim to cooked.
In an earlier post I explained each of the elements in the circuit, but I will repeat most of the explanations here. The direct answers to your questions are in bold. I used the circuit boards provided by American Models because they did contain usable parts and spanned the two trucks from which to draw current. I started by disassembling the car, removing the circuit board, and de-soldering and removing the incandescent light bulbs.
I drilled a small hole through the printed circuit line to break the connection as described on the left of the picture below. I did this so that I could insert a 22mH choke to bridge the connection. The choke was a recommendation for anyone who wanted to use the MTH DCS system and prevent interference with its signal to DCS-controlled locomotives. The choke is the black rectangle with the red outline. The break is represented by the disconnected yellow line below the choke image. If the car will never be used on a DCS system, the choke is not necessary.
The next element is the bridge rectifier, the gray circle in the diagram. The rectifier's job is to take in either DC current or alternating current and send out only the DC current required by the LEDs and the buck-boost module. The two yellow lines represent the current from the two trucks and connect to the proper legs of the rectifier. The rectifier cannot span the PCB board lines that are parallel on the board because those two lines are to be reserved for the "rectified" or "corrected" DC current out from the rectifier.
The rectified current out from the rectifier is represented by the black ( -) and the red ( + ) lines that can connect to the parallel printed circuit board lines on the PCB board. Be sure to note which line is going to be positive and which is negative because the buck boost converter has to connect to the right one. The capacitor, the blue cylinder in the diagram, also has to connect to the correct lines because it has a positive leg and a negative leg (represented by the white marking down the side of the capacitor. Capacitors have markings on them to show which leg is negative.) The idea behind the capacitor is that it acts as a "battery" to temporarily store a charge on it so that lights don't flicker when current from the wheels on the trucks sees slight interruptions due to dirty track or crossing switches. Capacitors DO reduce flicker; but unless track and wheels are clean in the first place, I found that they don't eliminate it.
The buck-boost converter has pads on each of the four corners for connections. Each is marked--two on one end for input and two on the other end for output. The red and black lines on the diagram represent the positive and negative current from the capacitor or, more easily, the correct parallel printed line on the PCB board. I just used the holes from a removed incandescent light bulb to solder a connection from the positive or negative line to the correct positive or negative input pad on the buck-boost module.
The buck-boost converters I used had voltage output settings too high for the LEDs when I removed them from their packages. To make initial adjustments, I hooked each one up to wires with alligator clips on both ends of the wire. I attached one end of each wire to the input ends of the modules and the other ends to the track. I applied 10 volts from the track and tested the voltage at the output pads of each converter module. The initial voltage was between 25 and 30 volts, so I turned the brass rheostat screw on each module counterclockwise so that the measured output was about 7-8 volts. If the track voltage was 5 volts, the module put out 7-8 volts. If the track voltage were 12 volts, the output would still be 7-8 volts; and that is how the lights stay "constant" even when the passenger train is moving fast or slowly. (It's easiest to adjust all the buck-boost converter modules in a batch rather than adjust each one to complete one car, then go to complete another car, and so forth.) I set all the readjusted modules aside. When I need one for the PCB board, I glued it to the underside of the PCB board, away from any windows so that it would not be visible. Then it was easy to solder connections to the module's pads to the old holes in the PCB board using small wires.
The LED light strips have adhesive on the the reverse side. Before I attached them to the PCB board, though, I soldered wires from the converter's output pads to the correct positive (red) and negative (black) inputs on the LED strips. The strips are marked as to + or - connections, and they have small solder spots on them to make the connection easier. (Getting a good connection at this point , however, was the most difficult part of the assembly and required testing multiple times to make sure the LEDs lit up.) Once I was convinced the connections were good and the LEDs lit up, I stripped off the waxy paper over the adhesive and glued the strips to the bottom of the PCB boards. Most, if not all, LED strips already have resistors attached to them to control current. The buck-boost converter alters the voltage to alter the light output from the LED strips. I used 12-volt strips because I already had some, and this type was the easiest to find.
I reattached the PCB boards to the under frames of each car but left the upper body off for further testing. Once I had finished all the cars--a long process because I included heavyweights, streamliners, Amtrak cars, and cabooses--I lined up all the cars of the same type on the same stretch of track and applied current to the track. The lighting varied a bit from car to car, but adjusting the brass rheostat on each converter allowed me to make the lighting entirely uniform for each car. As gunrunnerjohn points out, adjusting current is more controllable than adjusting voltage; but if the voltage from the buck-boost converter stays well below 12 volts for 12-volt LED strips, there is little danger from burning them out. Each car now had the same amount of illumination no matter if the track voltage was varied from 4.5 volts (for American Models DC locomotives pulling cars) up to 15 volts (for American Flyer Legacy AC locomotives). I moved each car along the track to check whether the connections were sound. After each car passed, I reattached the bodies to the frames.
The benefits outweigh the work involved: uniform lighting from car to car, uniform lighting at any speed above that requiring more than about 4 volts, low current draw, and minimum heat generated in each car. There are other ways to illuminate cars, but this worked for me.
Terry
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Interesting, thanks John. Looks like this strip can be cut in one LED increments. Six bucks for 5 ft.
Tom, That is $6.00 for 5 meters, somewhere over 15 ft, excellent price, and to be able to use individual LEDs is a bonus.
Ray
Perhaps a picture will also help. There are three versions of the AM passenger car lighting boards. The earliest, at the bottom of the picture just has the three incandescent bulbs. This came out of one of the long out of production lightweight 80’ scale cars when I replaced them with LED’s.
The one in the middle is likely the one Terry used and is out of a current production 70’ heavyweight coach. The board at the top is the newest AM LED version that is in some of the new heavyweights and is available for replacement use. The black LED boards have enough capacitance for 1/4 to 1/2 second power interruption.
These lighting boards are not designed to fit the Budd cars with their full interiors. It may be possible to adapt them for ceiling mounting, I have not tried that yet.
The second picture shows the LED board mounted in an AM 80’ sleeper. The outboard round holes are for 80’ cars and the inboard slotted holes are for the 70’ cars. They provide constant lighting with AC or DC conventional and with command control.
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Tom,
I would ad one more piece of info, I put my strips on the roof of my cars and did find a few came loose with the adhesive that is on them. When I do the installations now I use a little contact cement to hold the strips to the roof. I prefer when the room is dark that the light shines down towards the ground on the layout. If you do need to change the strip or as I have add a tail light to the observation car, I was still able to remove the strip and solder to it and re-install with some more contact cement.
Ray
I use a few spots of CA adhesive or hot glue to insure the strips don't come loose. As for low voltage operation, my regulator board will operate at any reasonable track voltage if you're using 5V LED strips, typically a train transformer starts out at 5-6 VAC, that works fine for the 5V strips.
Thanks again to everyone for your explanations and patience. John, your board sounds perfect, but at $20 a car, I couldn’t afford that even if was the installed, ready-to-run, price.
So Terry, I don’t need a choke with straight DC track power – okay, but what if I upgrade to DCC? When I Google 22mH chokes I see $3.00+ ones from Mouser while the 22R226C from Digi-Key is like 84¢. With that kind of difference, I assume I am looking at two different things and doing something wrong… my head is spinning.
Still overall, I think I starting to understand what needs to be done and more importantly, what parts to order – except for the LED strips. 5V or 12V, do I care other than perhaps price?
Probably thinking too much,
Tom Stoltz
in Maine
@Tom Stoltz posted:Thanks again to everyone for your explanations and patience. John, your board sounds perfect, but at $20 a car, I couldn’t afford that even if was the installed, ready-to-run, price.
I guess you didn't notice that was the price for two boards that would do two cars. 
