I’ve just started adding buildings to my railway (dcc controlled) and have started to drill holes in the baseboard for lights. I was originaly going to use an old dc controller to power the lights but I was wondering if it would be better to have a dcc decoder for the lights and get power from the tracks. has anyone done this? if so I have a few questions:
is it worth the hassle?
If so what wires on the decoder do I connect to the lights?
What decoder should i use?
can I have 1 decoder for all the lights or does each light need a decoder?
should I use LEDs or bulbs?
also could I put a decoder on a smoke generator and put it in a building?
I would stick with the DC supply. Using DCC strikes me as horrific waste of decoders, and booster capacity. Not to mention the increased possiblity that a short in the building wiring, would shut down the railroad.
If I remember correctly, most HO scale decoders can give you about 100-150 mA (at 12V) on the function outputs. Assuming that the lamp pulls 20mA @ 12V you can put up to 5 lamps per function - HOWEVER since they peak at 12V, they will be just over 50% brightness. You also have to account for the lamp’s inrush current so you wouldn’t want to put 5 lamps on the decoder’s outputs (probably only 3 or 4).
Though I gues a benefit is that most decoders have 2, 4,or 6 function outputs, so you could wire 6-24 bulbs on a single decoder (depending on the number of outputs available).
Just looking though, it appears that you’d need to use mobile decoders to do this,as all the stationary ones I can find info on are made to throw tortoise machines, and work in conjunction with signalling systems…
Your DCC system can only put out a limited amount of current. Without an extra booster, the biggest ones top out at 5 amps. You really want to save all of that for your locomotives. Strings of lights, even very small ones, will add up and severely limit your railroad.
Toggle switches are very cheap. You can cannibalize an old computer for a big power supply, or find a wall-wart with the right voltage for your lights. That’s a much cheaper solution than going DCC, unless you really feel that you need to control building lights from your throttle.
I built a DCC controller for my building lights that doesn’t draw power from the track. It has 3 outputs fixed always on, on/off DCC controlled and variable DCC controlled. Here’s the URL:
If you just want off/on you could use one decoder with an external DC power supply and a relay(s). The relay(s) would be tied to the function outputs and then you could switch off/on lights with DCC. I do it myself and I like it. It is more complicated than straight DC (i.e. old power pack etc…) but it depends upon your desires.
It might sound cool or be considered bragging rights, but that would be a waste of DCC power. An old DC power pack is what our club layout uses. A pair of #18 wires distributes the power around the layout. It has been in place for thirty five years, the KISS principle. We also use the same power for the slow motion turnout machines. When I installed block signals some years ago, it was easy to pull power for the electronics. We started running the NCE PH Pro five amp system five years ago and saw no good reason to change.
Using DCC to power building (and street) lights is sort of like using a brand-new Cadillac Escalade to haul fertilizer - especially if you have a beat-up old Toyota pickup, er… toy train power supply, available.
I, personally, am a big fan of de-centralized electricals. My turnout power is a single-purpose dedicated supply. Panel lights run off a toy train power pack. As I bring towns on line, their buildings will be lit from a number of separate toy train packs (collected at yard sales by my sister.) That way, if one system turns up its toes and dies, I can concentrate on it alone instead of trying to figure out where to start looking for the problem. The only thing that would shut me down completely is a house power failure.
Chuck (modeling Central Japan in September, 1964 - with help from a '94 Toyota X-cab)
I use a power supply canabilized from an old 486 computer. It puts out more than enough power for all the structure lights I’ll be using. On my last layout it was pulling over 70 bulbs without turning a hair.
The only reason I could imagine one would want to go to the expense and complexity of doing this would be if they wanted the lights in the buildings to turn on and off on some sort of an automatic schedule.
No
Depends on the effects you want. Hooking them to the motor output would be like having a dimmer switch.
You do realize that you could light the lamps from a DCC system without any decoders at all? If they are the right voltage just hook them directly to the bus. But if you are after the lighting effects like MARS, flashing, alternating ditch lamps for some reason, then you would choose the decoder that had the appropriate functions built in.
Once again it depends on what effect/control you are trying to accomplish. A decoder is limited by the amount of electrical current it can be loaded with, so that would be the limiting factor.
There is no “should”, what do you want to use?
Yes. That is a much more practical use of a decoder.
I’ll be the dissenting voice here. It really isn’t all that complicated and to get around many of the comments regarding pulling track power just attach a realy to the decoder function output and still use your external power supply. Use multiple relays each tied to a function output if you want to switch multiple zones. It is no different than what folks are recommending with a straight external power supply. It just costs one decoder and a relay (or however many you want to use). If you have just a handful of lights, you can likely power them straight from the decoder (check thge current ratings) and not worry about the small DCC power drain. I like being able to turn on/off the lights from anywhere (I use a wireless throttle). It is the same reason I use stationary decoders and routes for turnout control. I currently have around 60 lights being power off of my sctach built light controller.