Hello how many 12 volt bulbls can you light from the same cheap train set power pack. I use the track side so I can dim the light. I have no resistors in the line. I have 25 lights that light then they fade off. I have tryed two diferent power packs same thing happen’s. I am thinking to many lights? Thanks Frank
The GOR & GOW bulbs I use draw anywhere from 40ma up to 100ma at 12 volts. 25 bulbs at .04ma = 1 amp but 25 bulbs at .1ma = 2.5 amps. I would think any but the real cheapo power packs would handle 25 bulbs.
Mel
Modeling the early to mid 1950s SP in HO scale since 1951
My Model Railroad
http://melvineperry.blogspot.com/
Bakersfield, California
I’m beginning to realize that aging is not for wimps.
Look at the power pack label for amps it can supply.
Put your amp meter in series at the highest DC amp scale and see what the bulbs are drawing. Very easy.
I have done that over the years with bulbs that I did not have the specs for.
Rich
Hello ok It’s a life like power pack the blue one. 120 v input output 16v dc 7va max output. When I put the meter on just the power pack train side this is set all the way open. I get 15.62v dc and 2.98a. When I hook up the lights I get 7.39v and 1.23a. The lights only stay on about a min. I can watch the meter count down. The accessory hook ups I get 4.1v and .01a with out lights. With the lights 2.2v and .01a. The lights do the same when hooked up there as well. I am not sure what all that means? Thanks Frank
Something isn’t right! For one thing I’ve never seen a model railroad power pack rated that low, 7 VA? That’s .4375 amps, that’s marginal for a small can motor . . . . maybe Z gauge?
Edit:
The Life Like 390 Blue Power Supply is 7VA at 16 volts, I was very surprised to find that anything that puny was available. That power supply couldn’t fight its way out of a paper bag.
0-6-0 you need to get a real power supply!
Mel
Modeling the early to mid 1950s SP in HO scale since 1951
My Model Railroad
http://melvineperry.blogspot.com/
I have a couple of 12 volt DC, 5 amp power supplies I got on eBay. They were about $8 each, shipping included from China. They arrived in a few days and work fine. Lots of power for my accessory lights.
But, they do not have circuit breakers, so for each lighting bus I add a fuse block and a 4-amp fuse. Better safe than sorry, and a fuse is cheaper than a power supply.
One of several power supplies I use for “Hotel Power” on my layout is an MRC Controlmaster 20. Like the OP I have the lights wired to the throttle output and I usually like to have the voltage dialed down to about 8 volts unless there are visitors and I want the city lights to be a little brighter.
Normally at 11.5 volts I’m drawing 5.2 amps, well below the rated 8 amps (I never want to run anything close to the rated levels but about 15-20% below).
In my situation, If I leave the output at 11.5 volts and then turn on the C-M 20 the overload lamp will light and there will be no output. I have to dial down the throttle knob, turn on the power switch then dial up the voltage. This is my usual procedure anyway.
It may be a combination of the cold-inrush current of the incandescents and/or the circuitry of the transistorized throttle. Cold inrush current can be up to 14 times the usual resistance.
Other variable-voltage throttles (power-packs) may have similar behavior. You may have to bring the output up gradually.
Good Luck, Ed
The guys are right, you can pickup a good power supply off eBay for under $10. Use “switching power supply” in the eBay search.
Here is an example:
The sellers have pull down menus to select the voltage and current. There are many sellers to pick from.
I have purchased three 12 volt switching power supplies for the accessories on my layout. All work great! I use three DC to DC convertors to obtain 1.4 volts for my micro bulb vehicle lighting, 5 volts for my Arduinos and LED lighting from one 12 volt 10 amp switching power supplys. The second 12 volt 10 amp power supply uses a DC to DC convertor set to 8½ volts for my 12 volt Grain of Wheat/Rice structure lighting (reduced voltage f
I’ve standardized on 16 volt incandescents but I run them at 12 volts. This lets them run cooler and greatly extends bulb life.
It also gives a softer, “warmer” glow to the lamps, which better suits my Transition Era layout.
Smart-aleck answer, less than 25, obviously. LOL.
If they are 16V buld,s a 9 or 12V supply would be perfect. They will last nearly forever on the lower voltage, and nothing will look like it has a nuclear reactor planted int eh middle of it (light shining through structure walls). 12V bulbs - a 9 or 6V supply will be good. Then all you need is a simple on.off switch, plus there is no chance you could bump the control and turn the power up too high for the bulbs.
–Randy
Hello Guy’s I am kinda following. Electronics was always a tuff thing for me to follow. This is what I am trying to do I have 50 grain of rice 12 volt bulbs. This is buliding’s,yard lights ect. My layout is a 13’ x 15’ horse shoe shape. Most of the lighting is on the right 15’ side closest to the power about 38 light’s this is where the yard round house and other bulidnig’s are. The rest are buliding’s spaced out over the 13’ part and the left 15’. I would like to have them all work from one power source if I can ? I am not sure where to even start. Is there a book I can get at the library on something on line ? Or with this many lights am I going to need multiple power source’s? I never worked with the power source from eather of the link’s. Thanks Frank
You don’t need a book. Use an ohm’s law online calculator.
What current do the bulbs draw at twelve volts DC.
I would suggest running them at nine volts DC for longer life.
Buy a step down 12 volt to nine volt volage regulator from Amazon for a few dollars if you do not know how to make one.
I recently saw a two amp and five amp at Amazon.
Rich
Hello Rich I looked at the ohm’s calculator and I am not sure where to find the info to put in. I took a Altas power pack input 120vac 25w 0-14 vdc max 10va output 17vac max 15va. I took my meter and set to the train side turned the knob till I got 12v and 2.17a showing on the meter. When I hook up just one bulb I get 10.47v and 1.86a showing. So that means the bulb is using 1.53v and 0.31a? So if I want to light 50 of them at 100% I need 76.5 v and 15.5 a? I know I wont really need that much power. Because I wont have the light’s that bright. Can I make that much power and what would I need? or am I still missing something.Thanks Frank
Check your IM (Messages)
Mel
Modeling the early to mid 1950s SP in HO scale since 1951
My Model Railroad
http://melvineperry.blogspot.com/
Bakersfield, California
I’m beginning to realize that aging is not for wimps.
You don;t even need Ohm’s Law. You don’t even need to know who’s law it is, but in this case it’s Kirchoff. If you put light bulbs in parallel, the total current is the sum of each current. so if they are 30ma bulbs and you have 50 of them, that’s 1.5 amps. 50 x .030. So you need a power supply capable fo supplying at least 1.5 amps, and good practice says the total load should be no more than 75-80% of the capacity of the power supply. SO you really want a 1.9-2.0 amp power supply. You can always go higher - amps are drawn by the load not pushed in by the power supply, so a 10 amp power supply wont blow up your light bulbs that draw 1.5 amps. You would however want to provide some sort of fuse or circuit breaker because 10 amps at 12 volts is 120 watts which is a lot of heat.
–Randy
Hello ok I think I found two problems with my wiring. Some of my lights were not wired in parallel so I’ll fix that first. How big should the wire be feeding the lights? Mine is solid 18ga by my striper’s. Is this to small? I used phone line form there to the light’s it is the same size as the wire on the light is this wrong to? Can there be a light at the end of the parallel feeder’s ? Thanks Frank
18 Gauge is fine and Yes to Your other questions.
Take Care! [:D]
Frank
Small Tiny Light Bulbs
Between (2002-2004) I purchased may different sizes of light bulbs from Miniatronics (Micro Miniature Bulbs).
At that time, there were many different choices of sizes and many different choices of voltage.
Now Miniatronics is only selling one type of 1.5V 1.34MM (.053") Dia. 25mA incandescent bulb.
Code: 18-025-10 [10 pcs] Price = $15.95 and Code: 18-025-20 Price = $28.95
Miniature Light Bulbs
Any and all types of small model railroading Bulbs use an electrical filament. Just like any regular light bulb using an electrical filament, has an expiration usage time date. Any type of Constant vibration on a bulb will in time will break the wire tungsten filament.
Question?
How much longer will miniature light bulbs be manufactured?
Why Not Convert To LED’s?
An LED using the correct Current (voltage and amperage) will last for ever. LED’s being sold on Ebay, only cost pennies each and there are Thousands of different choices.
Ebay search = LED → Model Railroads & Trains
Caution
“White” LED’s give off a soft blue color tint, while “Warm White” LED’s give off a soft yellowish color tint.
Fact
LED’s are also used as lighted Diodes, to control V-DC voltage direction.
Warning
Each and every LED will require a Resistor. I use this excellent location for required calculation. (LED = Diode Forward Voltage)
http://led.linear1.org/1led.wiz
Example Connection
My Model Train Structures
I will be using small soft yellow
Not so. If you use a power supply with the correct voltage for the LED you don’t require a resistor.
Dave
Actually you do for any kind of permanent installation. A quick check with a couple batteries is ok for testing purposes only.
Hate to be that “copy-n-paste guy”, but this link will give you the reasons why …
Mark.