Hi Group,
I will be installing headlights to my HO locomotives soon.
The locomotives are a mix of Athearn, P2K and Atlas products that I
have reworked over the years in order to have a decent 1978/1981 Canadian National roster.
These will be operated with MRC Tech II (2500) DC power packs.
DCC is a real possibility for the near future.
I have made some tests with regular 1.5 V bulbs (with an N4001 diode to
have directional lighting) but I do not like this set up which makes
the intensity of the lights totaly dependent of the speed of the loco.
I have tried different bulbs (voltage) to solve this problem and found
that by using a 6.3V, 35ma bulb, I get almost constant directional and
powerfull lighting.
Is this simple basic set up dependable ?
Can it be used with DCC ?
Thanks for your input,
Michel from Québec
On DCC, when the headlights are on, they are full intensity all the time. If you want to use 1.5V bulbs, you’ll have to wire resistors to them (if you use DCC).
The “classic” constant lighting arrangement for analog DC is to wire 2 diodes in series for forward w/ 1 for reverse. Tap off of the end of the diode gang and attach the tap off wire to your 1.5 V. bulb. You’ll have full bright forward and dim in revrse. The diodes bleed off .7 V. each for 1.4 V. to the bulb in forward. This is subtracted from the voltage to the motor but you should still be able to run 99 MPH frt trains if that’s your thing.
Thanks guys , I appreciate the info.
Michel D.
Go get Joe Fugate’s video on Electrical for his Siskiyou layout, He talks about install lights–it sure helped me.
Here’s the constant w/reverse lighting circuit for DC I put in an earlier post:
I mount two white light LED’s inside the locmotive shell and then flare 1.5 mm fiber optic strands with a candle just large enough to fit in the headlight sockets…then i run the strands to the LED’s and hold them against the LED’s with heat shrink tubing…it makes a nice light and the fiber optics are flexible enough to also add ditch lights…the ditch lights are .75 mm strands of fiber optics…here’s a picture of a GP-35 with the fiber optic headlights (don’t have a good one of the ditch lights but this pic can give you an idea)
Here’s a link to some other constant voltage/directional lighting circuits. I’ve used some in my Athearn locomotives for years. And you can have the locomotive sit still and have nice bright lights.
http://www.mrollins.com/constant1.html