# Volts / Amps - Migration to LEDs???



## Ron045 (Feb 11, 2016)

I hope is the right area to post this question. Please notify me if it is not. This is my first post on this forum.

Tonight I was running an MTH O Gauge Railking Big Boy with 14 lighted coach cars and a lighted caboose (All conventional lighting).

My Z-4000 was at 18 volts and was reading 9 Amps. There were a couple of times where the Z4000 Red light would come on and the trains would stop.

If I migrated all the coach cars to LED's would that drop the Amps down? Thus making the trains run better?

Thanks!
Ron


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## DonR (Oct 18, 2012)

Definitely. LEDs take just a tiny fraction of the amp draw of 
incandescents. 14 lighted coaches would be a serious amp
draw if not LED. Likely there were 3 or 4 bulbs per car, right?

If you haven't bought your LEDs yet, you might want to
consider getting a reel of the warm white STRIP LIGHTS.
These take 12 v DC. What voltage is on the track
when you run your trains as desired speed?

Now, you are aware that LEDs don't
dim in the same way that the other bulbs do. They will go out
when their minimum voltage is reached as you slow
the train. 

Don


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## gunrunnerjohn (Nov 10, 2010)

Passenger Car Lighting With LEDs will get you started.

You should be able to drop your power consumption in those cars 90-95% and get better lighting in the bargain.

You can also get the circuitry packaged with intensity control 20110 LED Lighting Regulator, 2 Pcs.










Oh, LED's will dim like regular bulbs, just over a narrower range. The above regulators have intensity control. If you use the 12V strips, they're more appropriate for command operation, there are solutions for conventional uses as well. I would still use the strips, but I'd pair them with a voltage boosting module.

This DC-DC 4-35V to1.25-28V buck boost power supply module paired with a cheap bridge rectifier will allow operation down to 5V AC on the track.


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## Ron045 (Feb 11, 2016)

Great info DonR and Gunner. I run DCS with 18 volts about 99.98% of the time. So low voltage use does not concern me. Simple plug and play would suit me fine. 

vr
Ron


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## gunrunnerjohn (Nov 10, 2010)

The regulators on the Henning's site will give you good flicker-free lighting from a strip of LED's, they have the 22uh chokes for DCS compatibility, and also an intensity control to adjust the lighting to your preferences. You just connect track power to two of the connections, and the LED strip to the other two. I mount them with double-sided foam tape to wherever they will fit and be out of sight. You can also bend the tab of the regulator over if that helps hide them.

Here's a closer view of the module, note that the link above is for a pair of these.


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## Shdwdrgn (Dec 23, 2014)

The new adjustable regulators I recently got for my HO arduino conversion are even smaller. The module is 11/16 x 7/16 and supposedly will handle a continuous 1.8A. They can be adjusted between 1.0V to 17V and will accept up to 23V input. These are great for a wide variety of applications, HOWEVER, I would consider this to be overkill for simply running onboard LEDs. My advice would be to find some fixed 5V DC-DC regulators which can be found smaller and cheaper. With a fixed output, you don't have to fiddle with pre-calibrating them, and you can easily calculate the proper resistor to use. Buy the parts in bulk to save money and get all of your cars converted at once.

You DO know that you have to use the proper size resistor in series with LEDs to keep from blowing them up, right? Unless you get something like the 12V strips that John mentioned, which already have the resistor built in, however the lights will cut out much sooner. If you wire your own with a 5V regulator (or even lower, if you can find one -- LED's only need about 1.2V to work), then your track voltage can drop much lower before the LEDs turn off.


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## gunrunnerjohn (Nov 10, 2010)

There's lots of ways to skin this cat, I prefer constant current vs constant voltage. It gives you a much finer adjustment of intensity. When you use constant voltage, you're range from off to full brightness is only about a volt and a half for the 12V strips.

I suspect your regulators also have DC input and don't offer DCS compatibility as well, something that is important with O-gauge command layouts.


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## Shdwdrgn (Dec 23, 2014)

You're right, the regulators are just basic DC input. I'm not familiar with DCS, but would assume it is like most systems that put an AC signal on top of the DC voltage, in which case a cap on the input would filter it out anyway.

Now I'm curious, how exactly do you go about getting a fixed current? Everything I've ever seen for working with LEDs requires a resistor value calculated from the source voltage and the current requirements of the LED, but increasing the voltage would also increase the current that flows through. Are there current regulators available that are independent of the input voltage?


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## Ron045 (Feb 11, 2016)

gunrunnerjohn said:


> The regulators on the Henning's site will give you good flicker-free lighting from a strip of LED's, they have the 22uh chokes for DCS compatibility, and also an intensity control to adjust the lighting to your preferences. You just connect track power to two of the connections, and the LED strip to the other two. I mount them with double-sided foam tape to wherever they will fit and be out of sight. You can also bend the tab of the regulator over if that helps hide them.
> 
> Here's a closer view of the module, note that the link above is for a pair of these.
> 
> View attachment 145962


This seems like maybe the best way to go for someone who wants to do it cheaply, but doesn't want to get their hands too dirty. I'm NOT good with electronics, but I can solder power in and power out.

I did not see LED strips at Hennings. Do you suggest I just buy the roll on line as many others have? I found this roll of 300 lights for $9. 

Coupled with the Hennings regulators I estimate I couple upgrade each coach for $10.

I did see some LED bayonet bulbs. I may get a handful of them for my Lionel 260 bumpers on my two yards.

Thanks!
Ron


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## gunrunnerjohn (Nov 10, 2010)

Shdwdrgn said:


> You're right, the regulators are just basic DC input. I'm not familiar with DCS, but would assume it is like most systems that put an AC signal on top of the DC voltage, in which case a cap on the input would filter it out anyway.
> 
> Now I'm curious, how exactly do you go about getting a fixed current? Everything I've ever seen for working with LEDs requires a resistor value calculated from the source voltage and the current requirements of the LED, but increasing the voltage would also increase the current that flows through. Are there current regulators available that are independent of the input voltage?


You can create a regulator circuit for constant voltage or constant current. I use the common LM317T in a constant current configuration. I add a large capacitor for flicker resistance, and a small current adjustment pot for intensity control. Of course, my boards also take the AC and a bridge rectifies it before the regulator circuit, remember for O-gauge we're running on AC. Here's a page that talks about Constant current with the LM317 Regulator.

For the DCS, I add a 22uh choke to the input to prevent the large capacitor from killing the DCS signal on the track. DCS is not like DCC, and a capacitive load across the track will degrade the DCS carrier, the choke prevents that degradation. 

These modules were specifically engineered for O-gauge command operation with constant 16-18 VAC on the track.

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Ron045 said:


> This seems like maybe the best way to go for someone who wants to do it cheaply, but doesn't want to get their hands too dirty. I'm NOT good with electronics, but I can solder power in and power out.
> 
> I did not see LED strips at Hennings. Do you suggest I just buy the roll on line as many others have? I found this roll of 300 lights for $9.
> 
> ...


When I do cars, I use my regulator board and roll LEDs. I don't pay anything close to $9 for them, 

Here's a 5 meter strip of warm white LED's for $3.18, free shipping.


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