Constant Lighting Circuit for LED Illumination in Passenger Cars

https://ogrforum.com/...lighting-kits?page=5

I highly recommend these.

Yep, the ones John H mentioned. Great product and very affordable. Buy from Hennings Trains.

I agree with John and Rod.  I must have 10 or so installed in various cars.

Thanks to everyone...the Henning's module has been ordered!

Great choice!

I can heartily recommend the lighting modules from Henning's.

@gunrunnerjohn

I've been reading a lot of threads concerning LED lighting in passenger cars this weekend and have come away with two new questions.

1. Someone asked if there was a way to set the brightness of the lighting board by measuring the output so "like" cars would have the same brightness.   I believe you answered "yes, measure the current across the DC output".  Doesn't the multimeter need to be in series with one lead going from the board to the LED strip?   Or in this case, since the board is current limited it can be measured across the outputs?

2. Mentioned a few times was installing a resettable fuse between the two center rail power pickup rollers to prevent melting the lighting wires in the event a derailment.   In my mind the wires coming from the pickup rollers are joined into one, like an upside down Y.   Where is the fuse installed? On one wire leg between one roller and where both wires join together?  For some reason I'm having a hard time picturing this idea.

Many Thanks

ward

Well, if you buy a DC capable clamp-on meter, you don't have to break the line.

I have the BSIDE ACM91 AC/DC Clamp-On

The PTC fuse mention is installed in the lead between the two pickup rollers.  If you have a derailment, it's pretty common for one of the rollers to land on an outside rail.  If the other one remains on the center roller, the full transformer current is dumped across that wire.  I've replaced a number of those wires that were melted by the accident.

1. While that is one heckuva deal for a clamp-on meter than measures DC current, I think Ward is asking if he can simply place a garden-variety DMM in DC-current mode across the outputs of your lighting board.  As he points out, the board is current-limited so the meter will shunt (steal) all the current whether or not the lighting strip is connected.  So indeed he does not have to break the line.

2. In his upside down "Y" visualization, the PTC can go in either leg.  Agreed that most cars I've seen are wired as an "L" as you suggest.

@stan2004 posted:

1. While that is one heckuva deal for a clamp-on meter than measures DC current, I think Ward is asking if he can simply place a garden-variety DMM in DC-current mode across the outputs of your lighting board.  As he points out, the board is current-limited so the meter will shunt (steal) all the current whether or not the lighting strip is connected.  So indeed he does not have to break the line.

Well, yes!  That is one of the ways I test the modules.  After all, they're constant current modules.  So, if you just wanted to pre-set a current value, you could just line them up on the bench and one by one adjust the current outputs to be the same.  And, like you say, the meter should short out the LED strip and steal all the current, so even in-circuit should work, I confess to having not tried that.

@stan2004 posted:

2. In his upside down "Y" visualization, the PTC can go in either leg.  Agreed that most cars I've seen are wired as an "L" as you suggest.

Correct again, anywhere between the two pickups will do the trick.

Stan, as you said, that measurement works perfectly.  The meter indicated the constant current and the LED's remained dark.  I could go all the way up to the 45ma max of the module, and down to the minimum of around 2ma.

Stan and GRJ, Yes, that is what I was asking and thought I read earlier.   The install is going to be the same on the 6 cars I'm working on now so I'm setting up the LED strips and constant voltage boards on the bench. Then will work on the actual installs.

Looking at Stan's diagrams it finally clicked on how to install the resettable fuses.  

Many Thanks

Ward

Ward, be aware that any cars that use more 3-led sections than a standard coach, will need the output ma setting increased linearly, to get the same brightness as other cars. This applies to such things as dome cars and vista domes for instance.

say for example a coach uses 6 led sections @ 30ma output, 5ma each section. A dome car using 8 sections will need 8 x 5 = 40 ma to have the same brightness. Hope that makes sense. In practice I find 3.5 - 4 ma per section looks about right to my eye.

Rod

Rod, Thanks, I wasn't fully aware of that.    I'll keep that in mind.

Ward

I find around 25ma looks good to me in an 18" car, and for heavyweight cars where I use yellow, I up that to around 35ma as the yellow strips are quite a bit dimmer.  For the 18" dual-level Superliners, I'm using around 40ma I believe, I just tune them until I like what I see.

I've been working on two MTH RK 0-27 Madison cars.   I'm using warm white LEDs painted with Tamiya (I think) clear orange paint to give the LEDS more of an incandescent color.  So far 40mA seems to be the number. When I move on to finish the other 4 Madison cars, having the starting point for the current settings will helpful.

I expect when I upgrade the 20th Century Limited and Empire State Express passenger cars I stick with the warm white LEDs and then will have to turn down the mA.

Ward

Painting the LED's surely does reduce the light output, so I suspect they're more like the yellow LED's I used in some heavyweights.

Of the 9 cars I plan to upgrade this winter, 6 are streamliners that I think will look better with warm white and 3 are Madisons that I want to have the more orange color.  One roll of warm white and some paint will handle all of the cars.