# LED Car lighting question



## DonR (Oct 18, 2012)

I want to light my passenger cars using
the 12 vdc LED strip lights from the reel of 300 I have.

Know I'll need to fashion the power
pickups with insulated axle metal wheels.

Need a circuit to provide 12 vdc
from DCC track power and to
include Capacitor to calm flickering.

Thot I had seen something on this but
it didn't turn up in a search.

Don


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## gunrunnerjohn (Nov 10, 2010)

Not being a DCC person, but knowing a bit about LEDs and passenger car lighting, what voltage is available on the track? I know it's a modulated square wave, but I'm not sure what voltage you have to work with.


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## NIMT (Jan 6, 2011)

I make the circuits to do that, if you want to make your own shoot me a PM and I'll give you the specs.


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## DonR (Oct 18, 2012)

GimrunnerJohn:

My handy dandy and very cheapo multimeter
from Harbor Freight can't measure the
voltage correctly so don't know what's
actually on the track...I suspect it must
be about the same voltage as DC as used
on those systems. I understand it is
not a pure DC or AC.

Nimt:

Will be in touch.

Don


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## gunrunnerjohn (Nov 10, 2010)

I think Sean has you covered, he's the DCC expert around here.


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## NIMT (Jan 6, 2011)

We're working on it.
Just to note: DCC power on the rails can vary anywhere from 12v to 18v it's not DC and it's not AC... Yes that's right it actually an amalgamation of both DC and AC. it's very close to Square wave AC but has a slight variation to it.
Simply put a normal meter will not give you an accurate measurement of the voltage on the rails.
I've been doing DCC for 20+ years now and I've never had a problem due to the voltage on the rails being off, most good DCC systems regulate the power output to be within the safe working voltages automatically.
This is one reason to invest into good quality DCC equipment!


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## DonR (Oct 18, 2012)

Sean:

IT'S ALIVE!

Lighted up my first passenger car today using the rectifier
with capacitor you recommended and enuf resistance to drop
the DCC track voltage to just under 7 vdc to power
4-3 led strips. They fit perfectly in the 
observation car roof...

The light effect thru the car windows at that voltage is the ghostly
greenish white old flourescent tubes produced. They
are most likely what was used in these
silver side Santa Fe passenger cars. So 
it's perfect.

I even drilled out the fake rear red beacon
to light it.

Wheels are on order so it's not on the track
yet. I have a number of high quality relays.
I plan to use the gold plated nubs on
their leafs as wipers for power pickup.

If I can follow instructions, when i get
the wheels a rollin, I'll post thrilling pics.

Don


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## NIMT (Jan 6, 2011)

Excellent to hear!:thumbsup::thumbsup:


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## DonR (Oct 18, 2012)

Sean:

Do these strip LEDs need some sort of break-in period?

I installed the strips in 2 more silver side cars today.

Pretesting them I got strange effects.

When first powered up they glow full brightness for
a second, then ebb back to the lower brightness
I prefer.

At one point the brightness would ebb and flow sorta
making like the eerie special effects in old horror flicks...

(Note: I don't drink and solder at the same time)

Would these two effects be caused by the
capacitor in some way?

Just curious. It is not a problem...the lights do settle down
and look great.

Dib


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## gunrunnerjohn (Nov 10, 2010)

LED strips require no break-in, the effects you're seeing have to be due to the supply voltage.


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## NIMT (Jan 6, 2011)

Yes sounds like the capacitor is oscillating, is the drop resistor before or after the capacitor?


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## DonR (Oct 18, 2012)

The drop resistor, I installed, is before the
capacitor in the line from the track..of course there are the other 
resistors that are a part of the strips. The voltage going
to the strips is just under 7 vdc. Gives just the right
brightness for the cars.

Don


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## DonR (Oct 18, 2012)

Gunrunnerjohn...

I sure am glad you put us onto these
LED strip lights...they are so easy to
work with and perfect for lighting
just about everything on the layout.

I'm wondering what kind of 'gel' that
could be pasted over the LEDS to 
give a little 'warmer' light similar
to incandescent that would be
suitable for a caboose for example.

Don


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## gunrunnerjohn (Nov 10, 2010)

You could probably use something like parchment paper over the strip to defuse the light. You can also buy them in various color temperatures, look for the lower numbered ones for more yellow components to the lighting.


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## NIMT (Jan 6, 2011)

Move the resistor to after the capacitor, that would be why it's oscillating. Are you using cool whites (blue light) Or warm whites(yellow white)? I use all warm whites.
To soften up the cool whites you can use some yellow paint over the LED.


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