Question On The Installation of LED street lights and Lampposts

Ai... I am no expert in the field for sure, and always ask GRJ and Stan2004 for help when it comes to this stuff. I almost bought those same lamps that you did, but they didn't fit the look I was going for, so I built my own using some SMD LEDs. The application/wiring is the same though. 

I mounted the posts with a finish nail, and drill a hole right behind the post to run the wires through the layout. I used red/black wires just because that's what I had.

I soldered a resistor to the red leg of each light underneath the layout. I used a 150 ohm resistor because again, that's what I had. You could also solder the resistor to the black wire, doesn't make a difference. I just did all red.

Then I twisted the ends of all the reds together, and all the blacks together, and then connected the red and black to the voltage regulator/convertor module similar to the one you have pictured. 

Make sure your regulator output is adjusted to the DC voltage you need, BEFORE you connect the lamps, and that is based on the size of resistor they sent you.

It doesn't matter which way the resistor faces.... I do them all the same, but it doesn't matter what end is what.

No need to use a diode.

You can connect/run many of those lamps off of 1 of those modules.

Now I won't talk about watts, mA, series wiring, parallel wiring, current draw, ohms, and all that technical data, cuz it really doesn't mean anything to me. I just learned the hard way that LEDs are very sensitive to more voltage than required, even by 1 tenth of a volt. So you really need to know what size the resistor is they sent you with those lights. I'm sure GRJ and Stan, and several others can tell you by looking at the picture you posted.  

How many streetlights are involved?

Did you already buy that pictured LM317 module?

Are there any other lighting or related scenery/accessory devices that you'd like to tie in to your streetlight electrical "grid"?

Laidoff: Thanks for the information, your layout looks fantastic!

Stan2004: Yes, I ordered two of the LM317 modules, they should be here on Monday. Eventually I will have other lights (LED's) tied into this streetlight electrical "Grid".  

I say eventually because I don't have the area in a "Finished" state.  I'm installing what I have to in order to finish the area that lies below an elevated line of track.

It's easier to install this now than later when the EL is assembled above this area.

26 street lights total so far.   

If you use the 1K resistors, you wire each light/resistor combo in parallel with the others.  At 12 volts, it'll draw around 10ma for each light, 26 lights, will be 260ma, the LM317 module should do that without much issue.

Thanks Gunrunner!

Are these 1K resistors? (See Photo Below) 

If I add additional lights in the future (Same Specs as above) would it be better to go with a separate "Grid" (LM Module and power supply) or can this "Grid" handle more?

If the specs of the LM module are: Input: DC 0V ~ 30V / AC 0V ~ 22V  -  Output: DC 1.25V ~ 28V  -  Output current: 2A Max, 

If the Output current is 2A max then the limit of the LM module would be approx. 2000 mA?  So that is why the 260mA is no issue?

Thanks for all the help! 

I found some info on resisters Brown, Black, Red, Gold is 1K.

Here you go, the Rosetta Stone for resistors.

I think most of your questions have been answered except this one.

I found what I think are your lamps on the wehonest ebay store but can't for the life of me figure out which wire is "+" and which is "-".  As you've obviously figured out from yoru question, it will light up one way and not the other (LEDs are "DC" devices so polarity matters).

My suggestion is as follows:

1. Attach at 1K resistor to the "+" screw-terminal output of the LM317 module.

2. Power up the LM317 module with your 14VAC accessory output.

3. Dial up the voltage until the display reads 5V (or so).

4. Take the 2 wires from a streetlight, and touch touch one wire to the "-" screw-terminal output and the other wire to the 1K resistor.  The streetlight will light up, albeit dimly, in only one orientation.  This will determine which wire color is "+" and which is "-".

Now you know which color wire is "+" for each streetlamp version.

As LOS says, it doesn't matter which wire you solder the 1K resistor to...but to insure world peace, you minds as well be consistent and put the resistor on, say, the "+" wire.

Once you know the polarity of your lamps you can mess with the voltage level to find a suitable brightness.  5V will light them up dimly and the brightness of an individual streetlight will not change as you add more lights.  I figure you'll find a voltage in the 10 to 12V range to be suitable.

One advantage of using a voltage in this range is you've probably read here about the amazingly low-priced LED "strips" that run around 12V.  These have mostly been used for passenger car lights but are great for building interior lights, station platform lights, you name it.  You might find you can tap into your streetlight power "grid" to light these too.

As you correctly concluded, 2A=2000mA so powering "only" 260mA is not going to break the bank.

Stan / Gunrunner / John, thanks for all the info!  I'll be working on this during the week!

Edit: Never mind, The chart had it on there and I missed it...

To show how old some of my resistors are, they only have three bands!   The tolerance with no 4th band is 20%.

I was actually going to add that in my post, but figured that no one else has a giant box of unsorted resistors from (at least) the 60's, possibly WWII surplus.  I do have a fair amount of 10%'s sorted.  Most folks, I don't think are likely to run into anything less than 5% tolerance these days.  

Truthfully, with resistors costing around 2-3 cents in any quantity, I don't spend much time sorting resistors nowadays.

Probably why they are still in the same box, on the same shelf for more than 40 years now...

Probably.