I saw a listing for these capacitors on Ebay and they indicate they can be wired to a passenger car LED light to maintain power thru turnouts or dirty track. Is this all I would need is the capacitor wired in series with the LED’s? Just seems too simple.
SMD storage capacitor 470 uF 16 VDC
-Bob
With a few other components. This is rather an older site but it can get you started.
http://www.awrr.com/lighting.html
Some now use super caps. Much smaller with much more capacitance.
http://www.members.optusnet.com.au/nswmn/flicker_free_JB.htm
Super caps can be bought via ebay from China. A few buy them to build their own stay alive modules for DCC decoders.
Rich
I’ve tried several circuits to stop the flickering over many years and finally went to battery powered lighting. It’s a pain you know where but pretty much all non flickering passenger car lighting is just that. Some work better than others but the best I came up with is a 1 fared 5.5 volt super cap powered through a full wave bridge rectifier in series with a 1k resistor and a 5.1 volt zener diode but even that has it’s problems. I use 8 to 10 low level warm white LEDs with 10k resistors in each passenger drawing a total of 3 to 4ma.
There is very little ambient light, the LEDs are actually quite dim.
Mel
Modeling the early to mid 1950s SP in HO scale since 1951
My Model
Mel,
That is nice lighting in your SP car. I have tried several resistor values and the 2-3K range seems right to my eyes. I have been installing the adhesive strip SMD warm white LEDs in my Walther’s cars and they look quite good and for the most part don’t flicker much. I know wiper styles have an effect on how steady they light as well. I guess I will have to live with it for now until I settle on a ‘circuit design’ that I am comfortable with building. I do remember riding the NYC along the Hudson River many years ago and the lights would flicker every so often, just like my HO versions?
-Bob
Bob
As a kid I road the UP City of Los Angles and the SP Golden State. Memories of a 12 year old kid at 78 can be off a bit but I don’t remember the lights flickering so I made my Daylight passenger cars so that they won’t flicker.
My Mother, brother and I got stuck in deep snow at Donner Pass December 21, 1949 for about 10 hours. Everything held very good, didn’t get cold and lights stayed on. The SP sent a snow blower up to Donnor Pass from Sacramento to get us going. Quite a thrill for a 12 year old, not so much for my Mother.
I have two cabooses with the super caps that do pretty good, no flickering through turnouts and I keep my track super clean for my DCC operation. They work good enough for me so I don’t plan on changing them.
After screwing around with lighting for several years and not liking how the lighting looked I revamped all of my passenger cars for battery power, I didn’t like the first try with a battery in every car. Turni
The solution is very similar to the above, except you can optionally drop the diode from the capacitor lead. But you have to insert a 1kOhm resistor before each LED.
A very extensive, in-depth discussion recently on this very topic …
http://model-railroad-hobbyist.com/node/23755
Mark.
Mark:
Thanks for the link.
Dave
Bob,
Down the page in this part of my Night Scene thread, I discuss my car lighting.
http://cs.trains.com/mrr/f/88/t/213765.aspx?page=2
There’s a circuit digram in there somewhere.
I tend to use segments cut from LED light strips for mine. The 470 uf cap i the one I use most often and is commonly available, although sometimes I use a smaller one when space is an issue. With the LED strip segments, I’ve used resistance of up to over 100,000 ohms. Dimmer is better in most cases IMO. Much of the commerical car lighting is unprototypically bright, I guess so that it’s obviously lit even with room lights on, but I like it dim…[8D]
Well, it is “too simple.” Capacitors are DC devices, as are LEDs. I’m not sure about those particular capacitors, but if they are electrolytic they are polarized, like LEDs, and you must get your plusses and minuses correct. And, they would go in parallel with the LED-resistor combination, not in series.
If you are running DCC, you have a square wave coming in from the tracks, and you should add a bridge rectifier to get DC out of it. Likewise, DC provides +/- in one direction and -/+ in the other. The rectifier will take care of that, too.
This is the diagram I used for my passenger cars. They light the athearn shorties very nicely, and will work on just about any mess of dirty track. As far as LED’s, I used a spool of outside LEDs from Amazon for $12. I think they’re designed for 12v, but they work well and have a prototypical brightness.
Here’s an album of my cars. http://imgur.com/a/obSJx
You used 15,000 ohms for R2 ? Was that used to dim the LEDs to create a “glow” ?
Mark.
TheWizard:
Thanks for sharing your lighting diagram. Based on your pictures it works very well.
Dave
Yes. The cars are just kinda sorta visibly lit with the lights on, and when you turn the lights off the cars have a very even glow without being overbearing like the MTH or Walthers lighting kits.
I’m sure you could play with the resistor to increase brightness, but then they wouldn’t stay “on” as long if the track power gets cut. As they are now, they take a second or two to “charge”, but remain on for about 30 seconds before they start to dim, and take about a full minute before they go out.
I’ve used that identical circuit in my cabooses with one alteration - I used a 5 volt 1 farad super cap. R1 was calculated to drop the voltage to safe limits to use the 5 volt cap and R2 just made up the difference (R1 + R2) for the LEDs.
Many people have told me it shouldn’t work like that, but I built it back when these super caps were something new (13 years ago) and just “assumed” my logic was correct. Thirteen years later, these lit cabooses are still running and working !
Mark.
Yep. Shouldn’t matter as long as R1 << R2 and ALL your LEDs are in parallel (since you are using a 5V super cap)