Another LED constant lighting question for passenger cars . . .

The strips light at about 7volts, I have bench tested a car I just did with small K Line transformer work just fine.

I have used gunrunnerjohn's constant current driver with a CL2 on the roll strips that break off in sections of 3 leds. I just tested a caboose with only 3 and it lights at 6.6 volts ac track voltage. Fluke true rms meter.

Anyway, it's all about your driver circuit. the leds raw will light at 2.3 - 3.4 depending on the color. It's the driver circuitry converting the AC and controlling the voltage or current that uses the rest.

Consider this eBay module, auction #: 122186424028, $1.39.  Add a bridge rectifier in front of the input to convert the AC to DC, and you have constant intensity adjustable lighting with any input voltage.

Boost Buck DC adjustable step up down Converter XL6009 Module Voltage

Thanks John! will order a few and try 'em out!    Does this mean I don't need a limiting resistor just before the LED?

GRJ: How large is that device?

You would just set the voltage to the proper voltage from around 10V to 12V.  Each 3-LED chunk of the strips has a build-in resistor, no extra resistors needed.

rex desilets posted:

GRJ: How large is that device?

Looks to be about 1" x 2" footprint, there are no dimensions in the ad.

Ordered lots of parts on Ebay for my lighting project, but they all come on a slow boat from China.  10 - 25 days.   More likely,  25 days.     Good prices though!   

Ok, humor me a bit with my basic questions.. Can I use Henning's 20110 LED regulator to operate LEDs in conventional and TMCC?? If so, what LEDS should I purchase and where do I get them?? My layout is wired to run conventional via transformer (power on at 5v) or TMCC  using 135w bricks...

Here's a how-to writeup with lots of pictures of using a similar DC-to-DC voltage boosting module (plus bridge and capacitor) to drive the 12V LED strip for conventional voltage operation.

http://jcstudiosinc.com/Consta...-Using-12V-LED-Strip

This photo shows you relative sizes of the various elements.

"Ordered lots of parts on Ebay for my lighting project, but they all come on a slow boat from China.  10 - 25 days.   More likely,  25 days.     Good prices though! "

They have their New Years party going on right now.

The 20110 LED Regulator was really designed with command operation and constant voltage in mind.  I like the module Stan shows for conventional operation.  Had I known then what I know now, I might have attempted to do a fancier module with the capability of operating over a wide range of voltages.  I think that ship has sailed at this point.  It would probably be a larger module than the one I came up with, but of course it would also be more capable.

Thanks for your responses guys!! Greatly appreciated!!

I just finished my sixth car with John's module. Took about 20 minutes. I just take bulbs out and tie in to pickup wires in case the next owner wants  to use bulbs. Tucked the module in the vestibule with rubber cement. I added a two pin connector so the roof can be disconnected.  To John. 

Any "next owner" of my cars will have to live with LED's, I rip all the old stuff out except the one feed of power from the pickups.

This topic has rekindled my desire to convert some of my passenger cars to LED lighting. 

I found the following modules on Amazon for $12.98.

]WGCD 10pcs Mini 360 DC to DC Buck Converter Step Down Module 4.75V-23V to 1V-17V       

I realize I need to add a rectifier and capacitor for AC current input.  Does anyone know a reason not to use these units?

I have a good reason right here. $18 gets you two modules and the only thing to add is a light strip. That was my point in my post. I think it's a pretty good deal.

Those modules only handle 23V DC maximum, rectified 18V track power will usually exceed that, something to keep in mind.  I use similar modules that have a 28VDC maximum in a little P/S module I created.  You'll need at least a rectifier and a filter cap, and for DCS compatibility, the 22uh choke.  Here's The board I used and my module perched on top that  adds the choke, bridge, and filter caps.  Note the hole in the upper PCB to allow for voltage adjustment.

This is the schematic for the module.  I have a jumper option to use full-wave or half-wave rectification.  That's useful as most TMCC stuff has a common AC and DC ground.  If I use this in a TMCC environment where I want the DC to have a common ground, I use the half-wave feature.  If I don't mind the DC requiring total isolation, I use the more efficient full-wave feature.

John H posted:

I have a good reason right here. $18 gets you two modules and the only thing to add is a light strip. That was my point in my post. I think it's a pretty good deal.

 In Greg's defense, he's talking about ten of the modules for that price. Of course, you do have to add the other components to make a complete solution.

I think ten modules for $13 versus $18 for two is a better deal.  If l still bought from eBay l would get the modules GRJ recommended, but l don't.  

ETA*** GRJ posted while l was typing.