# Wiring for multiple voltage lights



## RGlaser

First, I know this forum is for advanced topics, and for me, anything electrical is an advanced topic. 

First, are "adapter" and "transformer" synonymous? I use them interchangeably, but am not sure. "Wall wart" is the best term I've seen.

I have multiple streetlight/spotlight sets from both Lemax and Dept 56 that I use on my layout. They are all battery operated and burn through batteries like there's no tomorrow. The ones that use 2 AA batteries can be plugged into a 3V adapter/transformer, and there are 4 jacks on the transformer. The ones that use 3 AA batteries can be plugged into a 4.5V transformer, and there are 3 jacks on the transformer. A couple of them don't even have the jack to plug into a transformer. Even though using the transformers saves me on the batteries, it's a monumental pain to plug in all of those transformers. I'd like to wire everything together, somehow, including a switch, and then have a wire or two going to a single plug.

Oh, I have a couple of things that require 2 C batteries, too.

Is this possible?????? If it is, and you can explain it to me, please use VERY basic instructions - think kindergarten!

Thanks!


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## Coolbreeze

You can use a dc transformer. Say 12 volts. You then use a resistor on the positive lead to drop the voltage. Example..in my other hobby we use led lights often. Leds typically are 3v but do vary. Our main voltage is 14 volts and we use a 330 ohm resistor, or which ever resistor is needed to drop the voltage down to our requirements.

Note when checking the volts after the resistor you must have the lights inline and on.

You can goto radio shack, get the assorted pack of ( i recommend 1/4w minimum for anything more then a led...led need 1/8 w) and start testing away. start with a higher value and go smaller till you get to where you need to


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## T-Man

Well you could group your battery dilemma. Get a good 12 volt DC power supply. Group two 4.5vtwo's and one 3v = 12 v. Place them in series. Or four 3 volters . You would have to test Three 4.5 volters for brightness.


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## RGlaser

Coolbreeze and T-Man, thank you.

T-Man - when you say "group them in series," I think you mean that I should take the end of one light string and wire it to the next one, etc., until I have the group that you've described. Say I end up with 8 various groups of 3-volters and 4.5-volters. Then what? Wire the ends of all of them together and hook them up (how???) to the 12 volt DC power supply? What would that 12 volt DC power supply be? One of the "wall wart" things, but that's 12 volt?

Sorry for what are probably extremely basic questions, but I wasn't kidding when I said I know next to nothing about electricity.


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## Reckers

RGlaser,

First, welcome to the forum! Second, any question is a good question----the answers lay the groundwork for the next guy who comes along. You are correct about series: you daisy-chain the lights. Your transformer has two wires: the "left hand" of the first light attaches to the first transformer wire, then it's right hand goes to light #2, then #3, and so on. Last light has one empty hand, and it attaches to the other transformer wire, completing the loop.
If you have a group of lights and each has a different voltage requirement, you make up teams of lights. A 3volt + a 3v + 3v + 3 volt =12 volts. Call that one team "A". connect them all in a series (daisy chain) and then attach one end of the chain via wire to one terminal post, the other end to the other post.
Now, go form team "B" out of 4 volt lights. 3 x 4 volts =12 volts. Attach them in series, get a second pair of terminal wires, and run them to the two posts on the transformer. Now you have two teams on the field, all lit up, each team using 12 volts.

At this point, you realize two things: first, there has to be a maximum number of these things one transformer can handle, and the second is you're getting an awful lot of wires on that transformer. Right on both counts.

Solving problem #1 requires no engineering degree: use your head and don't overload it. Excessive heat in the transformer, dim lights, etc. tell you it's time to stop. So do popped circuit breakers.

Solving #2 is more complex, but more elegant. Switch your thinking to water mains. A great big one runs down the middle of your street. Every house has the same load: 40 psi to have the shower, sink, and toilet work. That's your load, just like 12 volts is the electric load. Now, the water company doesn't run a separate pipe from the water plant to each house: it runs a big main, and then feeds smaller lines to each house, right? So, you want to do the same thing.

Choose a good location under your train layout and run a single line from one side of your transformer to there with a large-diameter wire: this is like your water main. Go to Radio Shack and describe what you're doing, and tell them you need a block to attach the main at one end and feeder wires to go out from it. They'll fix you up. Now, you have a heavy wire running to the block; you take feeder wires out from it to team "A", team B, team C, and so on. Run a second line and block from your other transformer post, and all three teams return to it. That way, you have only two heavy wires out of the transformer, and short feeders from your groups of lights. Saves you from running beaucoupe wire. Each team, by itself, draws only 12 volts.


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## RGlaser

Reckers -
AHA! If you'll pardon the pun, I see the light. The analogies were perfect. I can also see how this is scalable, and I'll mention to Radio Shack that I want to be able to handle future enhancements, so that I have some excess capacity.


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## T-Man

One problem is the electronics. Is it just LEDs or do they flash? If they have electronics the chain won't work The board will fry on the first one in line.Then you are stuck creating different voltage power supplies Like the warts, A 3v and a 4.5 v.

Now this is heavy. If you get a transformer 12v. You can build and filter out the two voltages. I did this with twelve volts dc because I run 555 flashers off of it.

See we are getting technical. These power supplies are just a bridge rectifer, voltage regulator, and resistors to tune the voltage and a capacitor to filter and make it friendly for the chips.

What do you think?
This is my thread


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## RGlaser

Well, T-Man,....I don't want to offend you, b/c I know you're trying to help, but that may as well be Swahili that you're writing, for all that I can understand of it. I am totally impressed by anybody who understands all that. For my purposes, I think I have the info I need. I'm not using LEDs, and nothing flashes. Once I understand the basics, then I will investigate more into the more complicated areas.


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## tankist

1. why go to radio shack and pay money for the snow when its winter and there is plenty out there to just pick up? it doesn't have to be 12V specifically. you can use old wireless phone brick (Panasonic's are usually at 6V) or old cell charger or whatever. and if you were good about throwing all this stuff before thinking its useless - look at your craiglist free section. 


2. _and I'll mention to Radio Shack that I want to be able to handle future enhancements, _ - do you really think the person there will know what you talking about? somehow i doubt, same exact thing when asking a best buy kid. it is your responsibility to know what power-draw you need.

3. _I'm not using LEDs_ - 
one word for you - BAD! 
start using them and enjoy less heat, less power draw, better light, more lifetime and if done right negligible cost (for our purposes). it is 2010 today after all.


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## T-Man

After reading my section you are at least exposed to it. It is a progressional curve. I am not offended. I normally assume the worst if I have to give any direction. Regular bulbs work fine and they are easy. Just ask and the more specific a question is the less confusing the answer will be. BE aware you didn't give any specifics on your lighting.

Anton sit!!! Goodboy!


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## Reckers

*LOL* Hey, Tankist! I was just told in a business meeting that incandescent bulb sales in the US are up by 70%, right now! People are apparently buying and hoarding them because they don't want to switch to LED's and those squirrelly flourescents.


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## tankist

we are talking model lighting, right?






oh well, i'll just keep


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## Reckers

That 70% was about household lighting. Jerking your chain over it was about having fun.


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## RGlaser

OK, finally, I have taken the plunge and took one "team" as Reckers described, and hooked it up as he described to a barrier strip from RS. Everything worked as you all said it would thumbsup so I'm ready to take care of all the lights now, not just Team A.

So, of course, I have a few more questions.

- I have a couple of light sets that use 2 C batteries, which is 1.5v. What is the difference between C batteries and AA batteries? Both draw 1.5v, so in my creation of "teams," does it matter that the previously-used batteries are different sizes, and the voltage is the important thing? One of them is a set of LED lights. Does that change anything? All other lights are non-LED - please don't beat me!
- What size wire should I use out from the 12v power supply to the barrier strips?
- How do I handle a situation where I don't have enough things to come up with a complete "team" of 12v? For example, say I only have to 4.5 volt items, and nothing else to come up with the additional 3 volts needed to fill out the team?

Thanks again for your help...it was great the way everything came together today!!

Ruth


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## Big Ed

RGlaser said:


> OK, finally, I have taken the plunge and took one "team" as Reckers described, and hooked it up as he described to a barrier strip from RS. Everything worked as you all said it would thumbsup so I'm ready to take care of all the lights now, not just Team A.
> 
> So, of course, I have a few more questions.
> 
> - I have a couple of light sets that use 2 C batteries, which is 1.5v. What is the difference between C batteries and AA batteries? Both draw 1.5v, so in my creation of "teams," does it matter that the previously-used batteries are different sizes, and the voltage is the important thing? One of them is a set of LED lights. Does that change anything? All other lights are non-LED - please don't beat me!
> - What size wire should I use out from the 12v power supply to the barrier strips?
> - How do I handle a situation where I don't have enough things to come up with a complete "team" of 12v? For example, say I only have to 4.5 volt items, and nothing else to come up with the additional 3 volts needed to fill out the team?
> 
> Thanks again for your help...it was great the way everything came together today!!
> 
> Ruth


Welcome back.
Wow it took you a long time to take the plunge.:laugh:

I can't help you as I don't speak Swahili neither.

But am learning from these posts, little by little.


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## T-Man

For gage wire anything between 18 and 22 should be fine.
You are correct 1.5 volts is 15 volts no matter cd or AA.

I do not think a series lineup of LED and NON LED will work the amperage drawn by the incadescent will burn out the LED.

Now a lesson An LED will take 3 volts so 4 in series will work with 12.

But you only have 3 so 12 volts - 9 volts / .02 amps = 150 ohms so a resistor of 150 up to 230 would be fine for ballpark.

A screw lamp draws 100ma

Lets say it 6 volt not 14 14 will work with 12 too.

12-6/.1= 60 ohms so lets say 60 to 180 ohms will work.

Get it? You will need the amperage the lights draw, if you can't get the 12 volts Radio Shack packages have that information.


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## RGlaser

Thanks, T-Man. I'm feeling a bit more confident now, so I'm off to RS later today. I will not wire the LED in with the non-LED, but instead, will add more LED! They look great, anyway!


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## T-Man

Since you are going there you can get lights and sockets. If you want a lot of white bulbs get a string of Xmas lights. They also have micro lights too.


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## Rich_Trains

Hi,
This is a good place to mention this. Big Lots, a place that sells overstocks, has mini LED xmas lights for half price. I picked up a few 20 light strings for $1.50 each. Longer strings were even less per light. As far as I know Big Lots is only in the West but I'm sure other parts of the country have similar stores.
Rich


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## gunrunnerjohn

FWIW, NEVER connect LED's to a power supply without some sort of current limiting.


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