Track-powered LED Rope Lights

Rafi: What are the power requirements of the rope lights? Are they 110vac or what?

I bought a strip of led lights off Amazon it came with a cheap dimmer and wall wart power supply.  They had adhesive backing, which if attached under the table, I figured would last six months.  So I got a toothpick(s) and the blue painters masking tape.  I pulled a section of the backing off and coated the adhesive with the brown colored contact cement.   I put masking tape over the led strip and taped it in place to the wood and whatever else got in the way.  The next day I carefully peeled the blue tape off and several strips have been there a year now with no problems.  You can remove them but some wood grain may come up also.

Rafi: All the rope lights I see on Amazon are the type that plug into an AC outlet. Track power cannot be used with them directly. But you could use a relay to attach to your siding switch as long as you isolate the 110 volts going through the relay for safety reasons. Is that what you're trying to do?

It would be useful to provide actual product specifications for questions like this.  Without them, we're just guessing on how you might accomplish your goals.

Guys,

Thanks for the thoughts and probing for more specificity. 

I’m looking for any recommendations on LED light ropes that can be hard wired into AC track power put out by a Z-4000. So that would be 21v at 180 watts max. I’m mainly looking to avoid plugging in a wall wart and instead have the rope turn on along with track power. 

I hope that’s clear/cogent enough—my apologies if I’m not fluent enough in electrical terminology and physics to be making sense here.

Thanks again,

Rafi

Thinking you might be using the wrong description. Most LED rope lights are 120 volt AC. What you want is LED strip lights. Approx 16 ft long . Buy the kit that uses the 12 volt transformer and use a relay like Leo recommends to turn them off and on. The switch could be a DPST. The LED strip can be cut down in groups of 3. 3, 6, 9, 12, etc. Connectors can be bought to allow you to use the cut off pieces. Research using and connecting LED strip lights. Google and you tube are your friends! Hope this helps!

Pete and Leo,

I think you’ve provided a great potential solution. I need to study up on relays in this sort of application but it may work! Leo, can you expound a little bit on your advice to isolate the 110v for safety?

Thanks again,

Rafi

Personally, I would NOT use 110 volt on the layout!! 12 volt DC is the way to do it!!

Rafi: The contacts of the relay will be carrying high power (110 - 120 volts) to the LED rope lights just like the AC outlets in the wall. That is a lot more power than what is generally found under the benchwork for O gauge trains. You need to put the high power wires and relay into an electrical box that will provide hazard protection. You don't want to bump into that stuff while your on your back under the layout. Also, a proper electrical box is good in the case of a disaster like floods, fire, etc. The cleanup folks and firemen don't want to run into unprotected high voltage in these situations.

The LED light tapes typically come in 5 meter lengths and are powered by 12VDC.  You can get strips rated for outdoor use that have a transparent cover over the LEDs, but that is not recommended for your use,  Get the indoor tapes.  The tapes come with double-sided adhesive to stick on smooth surfaces.  Most ACX plywood is not smooth enough for reliable long-term use.  Hardwood ply coated with urethane is fine.  I often stick the tapes onto aluminum angle and then screw the angle to the wood substrate.  (the angle also functions as  a light shield).  There are also tape mounting clips available to backup the adhesive.

Electrical: the tapes run on 12V DC.  They are basically groups of LEDs and resistors mounted on a flexible circuit board (the tape).  Each LED group is a segment along the tape and consists of 3 or 5 LEDs.  You can cut the tape at the division between each segment - you will see solder pads and a cut line.  You can cut the tape to the length you want and also join two tape segments together with a drop of solder across the pads (most of the 5 meter tapes I get have at lease one soldered joint in them).  When you get your first tape, plug it in to the power supply (which you also ordered, if not included, to test the LEDs).  The whole reel should light up.

So, the next challenge is taking track power from your siding and converting it to 12 VDC.  A 10 cent bridge rectifier will convert your track power to DC.  Feed the DC output of the bridge rectifier to a DC to DC converter board ($1 ea in a 20 pack on the river site).  Use the converter's voltage trim to adjust the output to 12V or less.  The tapes are dim-able with lower voltages.  Connect the converter output to the end of the LED tape.   Observe polarity.   The converter you buy should be able to supply the amperage needed by the length of tape it powers so check the specs on the tapes you buy and/or adjust the length of your tapes accordingly.

For your application the LED tape you buy doesn't have to be the high CRI stuff I use for museum lighting and photographic work.  There are many types of tapes with LED numbers (ex:5050) and number of LEDs per centimeter - it doesn't seem to matter for most installations.  You only need a warm or cool white LED tape ($15 or less) and a 12VDC power supply for testing.  The tapes and power supply come with barrel connectors.  With a bit of practice, you will be able to solder feed wires via the rectifier and converter to the tape segments you cut to length and install your lighting.

There are also solderless tape connectors to join two tapes and assorted barrel connectors for power connections available.   For the application I described, soldered power wires are the most reliable.

@Tracker John posted:

The LED light tapes typically come in 5 meter lengths and are powered by 12VDC.  You can get strips rated for outdoor use that have a transparent cover over the LEDs, but that is not recommended for your use,  Get the indoor tapes.  The tapes come with double-sided adhesive to stick on smooth surfaces.  Most ACX plywood is not smooth enough for reliable long-term use.  Hardwood ply coated with urethane is fine.  I often stick the tapes onto aluminum angle and then screw the angle to the wood substrate.  (the angle also functions as  a light shield).  There are also tape mounting clips available to backup the adhesive.

Electrical: the tapes run on 12V DC.  They are basically groups of LEDs and resistors mounted on a flexible circuit board (the tape).  Each LED group is a segment along the tape and consists of 3 or 5 LEDs.  You can cut the tape at the division between each segment - you will see solder pads and a cut line.  You can cut the tape to the length you want and also join two tape segments together with a drop of solder across the pads (most of the 5 meter tapes I get have at lease one soldered joint in them).  When you get your first tape, plug it in to the power supply (which you also ordered, if not included, to test the LEDs).  The whole reel should light up.

So, the next challenge is taking track power from your siding and converting it to 12 VDC.  A 10 cent bridge rectifier will convert your track power to DC.  Feed the DC output of the bridge rectifier to a DC to DC converter board ($1 ea in a 20 pack on the river site).  Use the converter's voltage trim to adjust the output to 12V or less.  The tapes are dim-able with lower voltages.  Connect the converter output to the end of the LED tape.   Observe polarity.   The converter you buy should be able to supply the amperage needed by the length of tape it powers so check the specs on the tapes you buy and/or adjust the length of your tapes accordingly.

For your application the LED tape you buy doesn't have to be the high CRI stuff I use for museum lighting and photographic work.  There are many types of tapes with LED numbers (ex:5050) and number of LEDs per centimeter - it doesn't seem to matter for most installations.  You only need a warm or cool white LED tape ($15 or less) and a 12VDC power supply for testing.  The tapes and power supply come with barrel connectors.  With a bit of practice, you will be able to solder feed wires via the rectifier and converter to the tape segments you cut to length and install your lighting.

There are also solderless tape connectors to join two tapes and assorted barrel connectors for power connections available.   For the application I described, soldered power wires are the most reliable.

John,

This is GOLD. This is precisely what I'm after. A couple points of clarification:

1). Can you point me to the "river site" that you mention?
2). Should I be looking for some key attributes/ratings on the bridge rectifier? ie voltage/amp Rectifiers are new territory for me so I'm learning here.
3). Same question for the DC to DC converter. Are there any particular specs that I should be filtering for?

Again, thanks so much for taking the time to post this information.

Thanks again,

Rafi

I mostly use Amazon as they list most of what I need for parts and Prime covers shipping.  eBay is another option.  For electronic components, Jameco, AllElectronics, Newark, Digikey, Mouser, et al are sources.  Jameco has low shipping costs for a few lightweight parts.

Your bridge rectifier should able to handle the peak AC voltage and the amp draw for the LEDs.  Parts rated at 2A or higher, and 50V or higher will work.  Assuming 18VAC (RMS) from your track, the peak voltage is less than 30V.

The DC to DC converter should be able input the rectified voltage from the siding.  Most of the ones I have looked at are rated for up to 48 VDC input.  Output amps should be 2A or higher.  The length of your LED tape is the deciding factor here, but the tapes I have used draw 2A for the whole reel.  The converters may include a voltage display - those cost more.

If you've been converted to strips (vs. ropes), take a look at this site which nicely summarizes 12V-DC powered LED strips.   I think the hardest part is knowing how much lighting you need, "how much" being measured in Lumens, Watts, number of LEDs, meters or feet of strip, etc.  I think the relationships and example used in the link is pretty good.  That is, can you imagine a traditional 40-Watt incandescent bulb, if the light could be distributed accordingly, lighting up your yard?  Or how about 2x 40 Watt bulbs.  Etc.

Ignore the prices in the link.  On Amazon, my guess is you'll spend say $10-15 for the LED strips from a U.S. Seller.  There will be many options for the electronics but to get the cart-before-horse, I suggest selecting the lighting before the electronics.

Separately, will you be running MTH-DCS command control on the yard?  If so, there is another consideration if you power the LED strip lighting from the 18V-21V AC track power.  There would be another component to add...but no need to complicate matters if DCS is not in the picture.

 Addendum: please comment on if (1) soldering is on/off the table, and (2)  you have a DMM / multimeter.

Stan, thanks for the thoughtful advice.

Yes, I am 100% on board with strips instead of ropes. Thanks for the suggestions-I am going to be researching all of this tonight.

And yes, DCS is going to be part of this equation alongside Legacy/TMCC. What do I need to consider on that front? I’m glad that you brought it up! I wouldn’t have guessed LED strips would interfere or vice versa in any way. 

soldering is not off of the table at all. I am not professional, but I can get things done if I need to. And yes, I have a multimeter.

Thanks again,

Rafi

Re:  WaveformLighting pricing on the site Stan referenced., my comment "the LED tape you buy doesn't have to be the high CRI stuff I use for museum lighting and photographic work" applies.  I used a reel of Waveform's 99CRI for photographic reproduction work - it's very very bright and draws more power than most LED tapes.  Too bright for layout applications (except my mini floodlight for the train cam ;-).

To get started, there are kits with a power supply and a reel of white LEDs for about $15 sold for "undercounter lighting".   LED reels w/o power supplies are less.  About the only differentiation among the LED strip vendors I see is the quality of the adhesive backing.

Get a DC to DC converter (or a pack of them).  This was the first on the river search I just did and matches the input/output requirements:
Valefod 10 Pack DC to DC High Efficiency Voltage Regulator 3.0-40V to 1.5-35V Buck Converter.

Here's a bridge rectifier that is appropriate: (Pack of 10 Pieces) Chanzon KBL406 Bridge Rectifier Diode 4A 600V KBL-4 (SIP-4) Single Phase, Full Wave 4 Amp 600 Volt.

I didn't mention a capacitor to smooth the ripple output of the rectifier.  I don't think it's needed as there is a cap pictured on the input side of the dc to dc converter I mentioned.

There are also AC to DC buck converters that have the rectifier and cap built into the board: Buck Converter, Yeeco AC/DC to DC Step Down Converter AC 2.5-27V DC 3-40V 24V 36V to DC 1.5-27V 12V Voltage Regulator Board 3A.

I haven't searched the electronic supply houses (Jameco etc.) but they also carry these components.

You can also review the forum's threads on passenger car LED lighting.  Lighting kits have a purpose-built power supply. 

@Rafi posted:

 

1). Can you point me to the "river site" that you mention?

That's a new one on me, but it's a reference to Amazon. Similarly, you'll see references to "the bay" (Ebay) and "that auction site" (same).

These arise from an old Forum legend (this place has been around since 2000) that mentioning Ebay in a post will cause it to get deleted as some sort of acceptable-use-policy violation. The truth is mostly that you're not supposed to link to a particular auction for  the purpose of ridiculing a clueless-sounding description, over-the-top pricing, or similar "will you look at this?" dog-piling on a seller.

---PCJ

A picture is worth a thousand words so....

18-21V AC track voltage enters on the left.  12V DC to the LED strip exits on the right.  If using DCS you should install a 22uH inductor (a.k.a. "DCS choke") in one of the AC inputs. Without this inductor, the capacitor in the AC-to-DC conversion process is known to drag down the DCS signal.

Then, to perform the AC-to-DC conversion you can use either an AC-in, DC-out converter module shown at top, or a DC-in, DC-out module shown at bottom.  The DC-in module requires an external bridge rectifier and additional capacitor.  That is, the DC-in module indeed has a small onboard capacitor but for the power levels you'll be working at you should add additional external capacitance.  Note that the AC-in module has such a larger capacitor.  The components are not expensive but when you only need 1 or 2 but have to buy a bag of 10 or 20 it can get tedious.

Both versions I show come with screw-terminals for input and output.  I happen to find this convenient but if willing to solder wires to the module you can probably save on cost.  I also show a DC-in version that has an integral DC voltmeter; I am not aware of an AC-in, DC-out converter with built-in voltmeter.  This can be handy if working under the layout in that you don't have to awkwardly mess with a voltmeter while adjusting the tiny screw which adjusts the output DC voltage (brightness of strip).  Or as discussed in previous post, you can get the basic (no voltmeter, no screw-terminal) version for less than $2 each when you buy a bag of 10.

As has been discussed, the LED strips in various lengths though you'll probably be buying a 5-meter rolls.  Unless you have a long-skinny 5m/16ft yard, I figure you'll be cutting the strip into multiple sections.  There are "cut-lines" every 3rd LED.  Then solder a pair of wires from + to + and - to -.  For an under-table yard I figure the LED strips are relatively close to the trains.  In other words you are not trying the illuminate a kitchen or living room.  Hence, I'm suggesting you won't be driving the LED strips at full-power (12V) but rather at maybe 10 or 11V using the adjustment screw on the converter.

If just getting started with these LED strips it is indeed difficult to guess-timate how many Lumens or Watts or whatever you need. 

I have no idea how large your under-table yard is but to ballpark some numbers, I'll say 20 Watts of power which you'll be "stealing" from the 180 Watts of available power on a Z-4000 track output.  Hobby-grade LEDs produce maybe 50-75 Lumens per Watt.  And there are power losses here and there.  Anyway, I'm thinking ~1000 Lumens - about the light you'd get from a pair of incandescent 40 Watt bulbs.  Your mileage may vary! 

PCJ—I face palmed when I realized river meant amazon. 🤦🏻🤣 thanks for the background as context, too!

John, this is extremely helpful—thank you. 

and Stan....

To say that you went above and beyond is a serious understatement. THANK YOU!!! Indeed, your pictures are worth tens of thousands of words. I have a lot of studying to do here but this looks...really fun!! Seriously...this could be pretty darn cool. 

Thanks again guys! 

Rafi