Any way to use the KATO pass car bulb sets w/ DCC?

[OldEastRR]

I really like the "warm glow" effect from the bulbs (when they aren't at full blast bright) which I think are more in tune with what the sleeper compartments in '50s trains looked like. However, with DCC's 22v AC the lights turn into heat blasters that melt the car roofs (they did this on DC too). Is there anyway I can salvage these bulbs for use in the cars w/o damage to the cars? 7-8 volts is probably the best range I'm looking for them.

[MK]

22 volts doesn't sound right and sounds quite high!     How did you measure?

[altohorn25]

They specifically say you are NOT suppose to use them for DCC applications (as you said, they melt the roofs because of the increased voltage used in DCC).

I wouldn't try it unless you fit resistors in the circuit.

Nate

[nickelplate759]

Unless you already have a lot of the bulb-style lights, it might be less trouble to change the color of the LED-style lights (with a marker, or something like a piece of Rosco lighting gel) than to modify the bulb-style light boards.

[atsf3751]

I use the Kato 11-212 LED light kit in all my Kato passenger trains and there is no issue with DCC. They also have another advantage, they do not flicker. The light is solid and steady even after many hours of running.

[peteski]

The only viable option I see to reduce the brightness and amount of heat is to rewire the bulbs from in-parallel to in-series. That will split the voltage between them and they will run at half brightness (and half the heat).  But I would still recommend replacing them with the LED units. If you don't like the stark white light, paint the LEDs with some Tamiya clear amber paint.

[mmagliaro]

How much current do those things draw, and how many bulbs are in there?

It might be possible to wire a resistor into the circuit in each car so the would burn nicely
on your track voltage.   But the current draw is probably high enough that it would require a big
resistor that will give off a lot of heat.  Even a 1W resistor is cumbersome in size and makes a lot of heat.
You could use a pair of 1/2W to spread out the footprint and the heat, I suppose.

Total current the car draws on DC at full 12v is the key thing to measure.  Get us that and we can
see if it's even feasible.

[peteski]

How much current do those things draw, and how many bulbs are in there?

It might be possible to wire a resistor into the circuit in each car so the would burn nicely
on your track voltage.   But the current draw is probably high enough that it would require a big
resistor that will give off a lot of heat.  Even a 1W resistor is cumbersome in size and makes a lot of heat.
You could use a pair of 1/2W to spread out the footprint and the heat, I suppose.

That is the big problem - heat dissipation. The total amount of power (heat) dissipated by 2 smaller wattage resistors sill still equal to the power dissapated by a single resistor with the same resistance (assuming that the total resistance is the same in each example).  IIRC, there are 2 12V light bulbs in those old Kato units. They were infamous for getting hot enough to melt the roofs (especially under DCC power).  That is why I recommended series connection.

[atsf3751]

The Kato LED light kits I mentioned include an amber filter that can be snapped over the LED if you are looking for an incandescent appearance.

[OldEastRR]

Hey, those bulbs melted roofs with DC power, too. Running a long heavy train meant cranking up the power.
There is only one bulb in each car. And thanks for all the suggestions about using the LED ones, I am using them in my cars too. But even with tinting and exposed film filters they don't look like bulb light. I assume it has something to do with light wavelength of each device.
Interior car lighting is somewhat of a craft for me. Not many people run their trains in the dark, even if they have lights in them, but it can be beautiful.  I'm not talking about the same light shining through every window in every car at the same intensity. I like to make the lighting varied in different cars and even different parts of cars. And eliminate it from showing where it shouldn't. To be in a dim-lit room and watch/listen to sound unit locos pulling cars with unlit baggage door windows in an illuminated baggage-RPO, "fluorescent" lights in the coaches, and cars with aisles and lounges lit by "flourescents" while in the same car there's warm "light bulb" glow in some sleeper compartments -- and some are completely dark -- is ... well, relaxing, satisfying, something like that.
Tho I have a NH layout I couldn't resist the challenge of lighting up the UP COLA domes (since KATO didn't). So I have a  diner dome with "light bulbs" in the dome and "flourecents" in the kitchen, running along in my lighted UP passenger train thru Connecticutt.
So I'm not being cheap, or have anything against LEDs, I like to use the bulbs for these effects. And big resistors are no problem ... there's a lot of space in passenger (and especially RPO) cars. If the resistor only gets slightly warm then it can be jammed right up against the plastic insides w/o worrying about melting anything.
Those LEDs are awfully bright at 13 volts DCC -- wouldn't hurt to cut down their power, too.

[C62-2]

Have you looked at the light from the 11-213 / 11-214 LED lights with the orange filter bit added? (see the lower picture on this page: http://www.katomodels.com/n/led_roomlight_clear/). The light is pretty warm, although it's not as yellow as the old incandescent ones. But those now look too yellow to me by comparison. The 11-211 / 11-212 are intended to look like the fluorescent lights that are common on Japanese trains, and seem too blue even for that unless you add the filter. The one advantage of the newer LED design is that the lighting is much more even, especially if you put a bit of light blocking tape to block the light from escaping at the joint between the LED holder and the big clear plastic piece.

[mmagliaro]

Peteski, the reason I proposed using two resistors in parallel is that they could be spaced apart (not like 1/8" apart, like at opposite ends of the car or something) just to spread the heat, rather than have it all concentrated at one point near a plastic part of the shell.

So, OldEastRR, there is only one bulb?  Really?

Can you measure the current draw of one car please?

I'll take a leap and guess it's a typical 60ma grain of wheat bulb.  If you want to knock off 6v,
6 / .060  = 100 ohm.  6 x .060 = 360 mW  So a 1/2 watt 100 ohm resistor will do it.   
But if the current draw is higher, your DCC track voltage is high enough that you need to knock off more than 6v, or you have 2 bulbs, that resistor wattage is going to go up, of course, so we really need that current draw and an accurate measure of the DCC track voltage if you even want to attempt this.

[jdcolombo]

Peteski, the reason I proposed using two resistors in parallel is that they could be spaced apart (not like 1/8" apart, like at opposite ends of the car or something) just to spread the heat, rather than have it all concentrated at one point near a plastic part of the shell.

So, OldEastRR, there is only one bulb?  Really?

Can you measure the current draw of one car please?

I'll take a leap and guess it's a typical 60ma grain of wheat bulb.  If you want to knock off 6v,
6 / .060  = 100 ohm.  6 x .060 = 360 mW  So a 1/2 watt 100 ohm resistor will do it.   
But if the current draw is higher, your DCC track voltage is high enough that you need to knock off more than 6v, or you have 2 bulbs, that resistor wattage is going to go up, of course, so we really need that current draw and an accurate measure of the DCC track voltage if you even want to attempt this.

Hi Max.  Your numbers are an excellent guess.   Information on the web indicates that those bulbs are 12v, 60ma.  But if you're dimming them by reducing voltage using a resistor, aren't you also likely reducing the current passing through the bulb?

And by the way, if Old East is correct that his DCC system is putting out 22v to the track, then you're dropping 15v, and 15v at 60ma is .9 watts, so you'd need a 1-watt resistor in that case.  That's a lot of heat.  If the DCC system really is putting out 22v, he needs to find a way to adjust that down to something reasonable, like 13v (or even lower for N scale; I use 11.5v).

John C.

[mmagliaro]

Hi Max.  Your numbers are an excellent guess.   Information on the web indicates that those bulbs are 12v, 60ma.  But if you're dimming them by reducing voltage using a resistor, aren't you also likely reducing the current passing through the bulb?

And by the way, if Old East is correct that his DCC system is putting out 22v to the track, then you're dropping 15v, and 15v at 60ma is .9 watts, so you'd need a 1-watt resistor in that case.  That's a lot of heat.  If the DCC system really is putting out 22v, he needs to find a way to adjust that down to something reasonable, like 13v (or even lower for N scale; I use 11.5v).

John C.

Good point.  Filament bulbs are very nonlinear devices.  I tested a GOW bulb here and it draws about 50% more current at 12v than it does at 6v.   Okay, so let's call it 45 mA at 6v.  Therefore  6 x 45  270mW,  just over 1/4 watt, so you still need a 1/2 watt resistor.  And the value 6/.045 = 133, so a 120 ohm resistor would be closer to what you want here.

As for the 22v, I'm just not buying that.  That can't be right.  Does any DCC booster let you run it that high?
And if it is, something is wrong.  I'll go along assuming he gets that under control.

Until we get actual measurements from OldEastRR, these are all guesses anyway.

[jdcolombo]

A Digitrax Chief will put 20v to the rails on the O-scale setting.  Not sure if the Zephyr is capable of that or not, but 22v isn't out of the realm of possibility.  Nevertheless, like you, I think it is highly improbable.

John C.