Large Scale Central

LED light help!

Electronics
#1

I recently purchased a roll of LED lights on a strip (5/16 wide strip). Thought that I could use them for passenger car lighting, and for building lights, as they are cuttable into length of three micro LEDs per section. Noticed that Micro-Mark has a teaser on page T7 of there fall catalog that appears to be the same thing… There is a “3M” adhesive on the back of the strip. I’m not an electronic ace by any means, but I can solder up basic components. Heres whats up. The system is powered by a 12vDC wall brick.

The strip has 300 LEDs total, they appear to be 10 sets of 30 LEDs strips. Each set has 10 sections of 3 LEDs and a Resistor.

Each 30 bulb set is soldered together with the next set, at the + - tabs

The three bulb set appears to have “Cut Here” marks between each 3 light set. Aprox. 2" long.

OK Guys… The Transformer will light all 300 light with 12VDC 900mA output. If I start cutting up this strip into 3 light sections, what am I going to need to drive these lights without frying them? Will they run on a lower voltage then 12VDC? If so how low? And what wattage would be needed at what volts per strip of 3 lights. + any other circuitry that I might need to make these work? Thanks ahead of time…

#2

Each section is 12 volts. They will light around 9.

each section being 12 volts, all answers to all voltage questions is 12 volts.

you have 100 sections each drawing 900 ma and that means that 1 section draws 9 ma… if you want to know watts, multiply volts (12) times current (0.009 amp) times number of sections.

Greg

p.s. make sure you have enough brightness at 9 ma per section.

#3

I’ve used about 3 to 4 sections (of 3 leds each) and stuck them in one of my passenger cars and powered them with just a 9V battery and they lit up to my satisfaction. In fact to test and verify that the whole roll was working I used a 9V battery to see the whole roll light up. That worked as a quick verification test. As long as the current limiting resistor is there and in series with the power source, and the power source isn’t too big it should be ok (you’d have to do the math to make sure the current doesn’t get too high - >9ma per section, otherwise the LEDs could burn out).

#4

I also use a PP3 9v battery via a push switch on two lots of 3 led strips in a couple of coaches. No problems…

#5

I used a full strip down the center of my bashed Aristo Sierra passenger cars and run them off of a 9v battery which is hidden in the restroom. I wired in a latching reed switch next to the top of the roof so I can turn the lights on and off with a magnet. Works fine and looks great.
Dennis

#6

For DCC, I placed 2 strips in series with a bridge rectifier and a 100 uf cap in passenger cars. Works great!!
My DCC system is set at 24 volts output to the track.

#7

Same here, years ago… but larger cap

Greg

#8

Each section contains 3 LEDs and a resistor in series. The strip has them all connected in parallel. Each section of 3 is designed to run on 12v and draws about 20mA. 9v will likely light them nicely.

See the two round “bubbles” on each side of the cut line? Use an xacto to pop the bubble off and there’s a solder pad underneath you can solder a wire onto. Tin your wire, and press it onto the solder pad with your hot soldering iron.

You can use as many or as few of these 3 led sections as you like.

#9

All true but wasn’t all this information in the first post by the OP?

In the ones I have, the “bubbles” are solder, pop them off and you destroy the copper film they are soldered to.

Do you have some of these Tom?

Greg

#10

I hope to take the plunge into led lighting this year.

While it doesn’t appear to be rocket science, I’ve not done hands on yet.

saw a video on doing lights
how to make miniature park lights - in
http://www.choochoobarn.com/videos/

he appears to be using led strips similar to what you folks are using here.

would I be farther ahead just buying individual leds, or getting a strip to play with.

looking for singles, not triples.

feed back appreciated.

CD

#11

For 9 volt battery operation I would change the resistor to a lower value to get brighter lights and as Greg pointed out the current appears to be 9ma at 12 volts, so at 9 volts the current must be less than that.

Also, lowering the resistor value will allow the lights to remain lit as the battery output lessens with use.