When to use light bulbs over LEDs?


P

Psapple83

Member
Hey everyone,

I'm looking at purchasing a bunch of lights, and I'm wondering if there is ever a case in which I would want to purchase a light bulb (such as a grain of wheat/rice/dust, etc.) over an LED? I'm looking at buying all kinds of lights from street lamps to in-structure lighting to something you'd see in a Mine (picture below- I have no idea if this is LED or Light bulb). And I just want to make sure I'm not missing some obvious reason not to use in LED in certain cases.

IMG_1625.jpg
thanks,
Silas
 
IMHO for locos use LED for areas like the mine I would use a bulb, It just gives the more realistic look. Leds look so much more better in locos cause they give you that super bright pin point lighting just like they wold look on a real loco. bulbs give you the droned out wide angle style light, I think in building and all that bulbs look the best because like I said before it looks more like they should.
 
Bulbs are also more useful where space is limited for resistors that must be used with LED's to reduce voltage to the point where the LED's won't be burned out. Also, LED's are polarity specific. If you are reversing the polarity of DC current, the the LED's will only be on when the current is in one direction. For example, I use bulbs where I have them connected across track gaps to determine if the polarities match. LED's must be used on signal lights that have plastic housing, as bulbs will get too hot. I use brass signals where I use 12-14v bulbs.
 
Good question and replies. I was going to replace my bulbs with LEDS (for buildings, street lights etc). After reading this, am sticking with the bulbs.

Cheers,

wombat457
 
Psapple83 said:
I just want to make sure I'm not missing some obvious reason not to use in LED in certain cases.
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I still use light bulbs in a few instances. First is in marker lamps and lanterns (such as caboose, observation cars, and some locos) where the light is needed to shine all around. I could use 4 surface mount sized LEDs, but that is such tiny precision and detailed work it is a real hassle. It is much easier to just pop a blub into the fixture and put colored lenses around the lamp.

Second is for locomotive headlamps (or observation car tail lamps) where I want to use DCC effects such as the Mars Lamp and Gyro Light. Since the effects are usually done by varying the voltage, a lamp responds much better than an LED would. ... Now there is a feature that is needed on decoders. Have a CV to set whether the lighting effects work based on voltage for lamps or based on current for LEDs.

I suppose cost could still be a factor. A string of 300 Christmas bulbs to light a massive city could be had for $0.75 after Christmas, while a similar number of LEDs is still in the $18 range.
 
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Forum:

I agree with WC3026, in most cases stay with LED's for loco headlights and regular lamps where the source of the light will be seen. The lamps provide a more natural glow and will cast a better lighting effect.

One note when using lamps, try to use lamps of a similar voltage to make the wiring easier. Run a two wire buss under your layout to power the lighting. Use an adjustable power source and wire a voltage meter between the power source and the lamps. Run the lamps at 10 volts to extend their life. Lamps make also last longer when powered by DC as opposed to AC current.

Thanks.

Greg
 
I would say use LEDs for more modern diesels and such, as first gen diesels used incandescent bulbs. I would also use bulbs on steamers as well. An LED just doesn't give that "glow" associated with the older headlights. Nowadays, they have halogens, and such for the diesels so they do really put out a lot of light.
 
Greg@mnrr said:
and regular lamps where the source of the light will be seen.
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Good point. This F unit would look pretty silly with two monster LEDs instead of the four prototypical bulbs. Once again I assume with a lot of work one could trim down and fit a couple surface mount LEDs into the headlamp fixture, but....

nosejobsmalh.jpg
 
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Is there a standard for max voltage for bulbs? I hear lots of stories about the bulb melting whatever its close to- and it would be nice not to ever worry about that.
 
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I agree with Cjcrescent on the use of lamps for earlier diesels, but the "DayGlow" LED's that were offered several years ago, do appear to provide that incandescent look. also, there's new "micro" LED's on the market that would work from classification lights and other applications.

Thanks.

Greg
 
I have a set of Proto Power SD60s that I swapped the headlights out for grain of wheat bulbs. After a short run, I noticed the roof of one unit had a hole being melted in it from the light bulb. I put an A/C unit over the hole to cover it and put a higher value resistor in line with the bulb.
 
Psapple83 said:
Is there a standard for max voltage for bulbs? I hear lots of stories about the bulb melting whatever its close to- and it would be nice not to ever worry about that.
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Yeah, there always is, just in the sense that an incandescent can only take so much voltage before the filament will just break under the current load. Same way a fuse works. But the thing is, you've usually got just a constant voltage on any given accessory buss. While you can run a 24V incandescent on a 12V buss, the bulb will be very dim. That does, of course, limit heat but it also doesn't put out much light. Generally speaking, the brighter the bulb shines, the more heat it puts off. Even dimmer bulbs can put off enough heat that even if they don't outright melt plastic, they can eventually cause what they're mounted in to sag, warp or discolor after repeated long-term use. As one other poster noted, it's a good idea to use LEDs in applications where the bulb is completely enclosed in plastic and can't dissipate heat. Bulbs that hang out of street lamps or are in open-air mounts inside buildings etc. will always work just fine.
 
Psapple83 said:
Is there a standard for max voltage for bulbs?
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No, each bulb will have its own set of specifications. The incandescent ones in the loco I put in the picture above are 1.5V. I run them at 1.2V to 1.3V. Grain of wheat and grain of rice bulbs can be found for almost any voltage. 6V, 9V, 12V, 13V, 16V, and 18V are common. Powering a bulb at the exactly its rated voltage will eventually burn it out. Running slightly less and they will last a long time. There is a fire station in California that still has an original Edison bulb burning. It has been on almost non-stop for over 110 years now. I assume the bulb accidentally got an extra turn or two in its filament, raising its voltage tolerance.

I hear lots of stories about the bulb melting whatever its close to-
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That is a different issue. Generally filament bulbs produce 20% light and 80% heat. Even running less than the full voltage can still heat things up. I used to use a lot of aluminum foil to dissipate heat. The 1.5V micro-minature bulbs I use have not yet melted anything - yet.

This accident was from an 18V bulb on a Railcommand 17.5V system. Bulb was just too close to the side.
MeltDown.JPG
 
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Iron Horseman said:
No, each bulb will have its own set of specifications. The incandescent ones in the loco I put in the picture above are 1.5V. I run them at 1.2V to 1.3V. Grain of wheat and grain of rice bulbs can be found for almost any voltage. 6V, 9V, 12V, 13V, 16V, and 18V are common. Powering a bulb at the exactly its rated voltage will eventually burn it out. Running slightly less and they will last a long time. There is a fire station in California that still has an original Edison bulb burning. It has been on almost non-stop for over 110 years now. I assume the bulb accidentally got an extra turn or two in its filament, raising its voltage tolerance.

That is a different issue. Generally filament bulbs produce 20% light and 80% heat. Even running less than the full voltage can still heat things up. I used to use a lot of aluminum foil to dissipate heat. The 1.5V micro-minature bulbs I use have not yet melted anything - yet.

This accident was from an 18V bulb on a Railcommand 17.5V system. Bulb was just too close to the side.
[/img]http://www.walkersquawker.net/images/MeltDown.JPG[/img]
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Ouch!

So if I am running a 12vdc bus, I should get 13v or 16v bulbs if its in open space and I'm not using an LED in that building?
 
This is a great thread! I learn so much from you guys!

Only things I can add:

Current is much lower in LEDs

Incandescent lamps produce heat.
 
Forum:

Many older DCC decoders and perhaps some of the newer ones are without resistors for lighting and have a higher in-rush of voltage when the decoder is first powered up. This in-rush of current could burn out many the headlights of many locos. As a general practice it was and is a good idea to install a dropping resistor with the lamps used in DCC loco's.

As a suggestion, when using lamps for loco lighting, test the lamp first with a resistor and allow it to burn for several minutes to determine how much heat is being generated. Too hot, increase the size of the resistor and then retest.

Like Iron Horseman stated there is a lamp that been burning in a fire station for over a hundred years. An old building maintenance trick was to use 240 volt lamps in 110 or 120 applications like exit lights and elevators. The higher rated 240 volt lamps will burn for an extremely long period of time. I know of some 240 volt lamps that have been in service for 20 plus years in exit lights.

Thanks.

Greg
 
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