Constant Lighting for DC Passenger Cars

[JakeTurner11]

I'm sure this has been discussed before, i just can't find anything for DC layouts. I'm trying to add a few LED's to my passenger cars, and am not sure what kind of capacitor I need in order to keep the lights flicker free. I've read about bridge rectifiers but I'm not sure if thats just a DCC thing. I'm hoping I can just add a capacitor and be good to go. Thanks for your help! 

[gregc]

did you try cs.trains.com constant lighting dc

[JakeTurner11]

I googled, but didnt try trains.com. 

 

Thanks

[richg1998]

JakeTurner11

I googled, but didnt try trains.com. 

 

Thanks

 

A little trick I learned a few years ago was to include trains.com in the Google search text. Not always necessary though

Rich

[RR_Mel]

Operating on DC you will need a bridge rectifier if you want the car lighting to work in both directions.  When I was using super caps to prevent flickering I used a 1 fared cap.  The super caps work OK but they are not my way of lighting my cars, especially on DC.  The LED brightness will vary with voltage.  If you set the brightness for normal running say around 8 or 9 volts then when you’re running at a creep 4 to 5 volts they will be dim.

 

I tried using a 4 volt regulator and that worked until I dropped the speed below 4½ volts then the lights started to dim.  It isn’t very noticeable when using the lower voltage and they would work until the voltage dropped below 3 volts then the LEDs quit.  White LEDs require a bit over 2.9 volts to put out light.  I normally do a lot of slow running so that wouldn’t work for me in DC, no problems on DCC where the voltage is constant at 15 volts.

 

 

 

 

 

 

Mel

 

 

My Model Railroad   

http://melvineperry.blogspot.com/

 

Bakersfield, California

 

I'm beginning to realize that aging is not for wimps.

 

[Mark R.]

Batteries.  

Mark.

[rrinker]

 Really batteries are probably the only practical solution. For the whole rectifier/cuper capacitor thing to actually work to keep the lights on during station stops you would have to run the train with the voltage high enough to get the capacitor charged up enough, which depending on the rest of the set up may be too fast for your layout. The simplest for of this would need somewhere around 4.5-6 volts to charge up the 3.3V supercapacitor via a bridge rectifier (2 diode drops) which is getting close to half throttle. If you are running sound locos on DC then you'll already have the throttle turned up way past this just to make the sounds turn on before anything moves, so it won;t be a problem, but the better quality modern locos without sound will be moving before the track voltage gets this high, and the first train out fo the station then might not have lights until you get moving at some speed. Then it has to stay running at speed long enough to charge up, then you cna slow down and stop and the lights will remain on for a significant amount of time.

 Batteries work regardless of the track power system. Rapido's light kits use a magnetic want to turn the lights on and off, so no lifting the cars to flip a switch on the bottom. 

 Back in the day there were schemes that fed high frquency AC on the rails, this tended to not affect the motors in locos but light bulbs don;t care and so they lit up. With the electronics in so many modern locos, this is probably not a good thing to try any more.

 Long before DCC, this was always another of the advantages touted for the early carrier control systems. Constant voltage on the rails = lights always stay on.

                                  --Randy

 

[RR_Mel]

I use rechargeable Lithium Coin Cells in my shorty passenger cars and AA Lithium cells for my 72’ Athearn passenger cars.

 

I charge the Coin Cell batteries from track power through a full wave bridge chip and a series resistor.  I turn the lights on and off using a magnet to trip a latching read switch.

 

The LIR 2032 Coin will easily handle a half dozen LEDs at low current, I don’t run any of my passenger cars very bright because to me they look toy like when bright, normally 1ma or less per LED.

 

They’ve been in service for about three years and the only time I have to charge them is when I forget to turn them off.

 

The link is to my blog post on my battery powered car lighting.

 

https://melvineperry.blogspot.com/2016/04/april-15-2016-more-car-lighting.html

 

 

 

Mel

 

 

My Model Railroad   

http://melvineperry.blogspot.com/

 

Bakersfield, California

 

I'm beginning to realize that aging is not for wimps.