Advise on RGB mini tree

Brettus

Brettus
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Hi guys

After going to this years Brisbane mini it has got me thinking about my first years computerized lighting setup. Was looking at setting up mini trees in the front garden this year and was first going to use three sets of 150 led lights in different colours. But after today have decided I am going to use dumb RGB lights instead. I was looking at getting Christmas creations mini tree frames and wrap them in 100 RGB lights. The frames stand about 90cm tall and have a base of 40cm.

These are the lights I was going to use http://www.aliexpress.com/fm-store/701799/209889132-522236867/IP68-DC12V-input-12mm-through-hole-LED-channel-letter-RGB-color-100pcs-a-string.html

My question is 100 going to be enough??? Or do I need more??? Have people got pictures of there RGB mini trees???
 

angus40

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i would look for the 5v version of these , i have them in 5v and i think 100 count would be fine for you .

imo 12v strings are a waste of power unless your running multiple strings on 1 output .

here is a video of 50 count 5v rgb . you will see how bright they are .

https://vimeo.com/35071166
 

Mike

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These lights are very bright comapred to the standard LED's so for that size tree I should imagine 100 would be plenty.

Why not make your own mini trees? They are simple enough to do. Its basically a tomato cage modified to suit. Bunnings has them in various sizes.
Just do one and try it out, see if you like it

I disagree with Angus though on the 5v versions. Reason for this is you will be able to run more lights off the 12v than on the 5v due to voltage drop, possibly cancelling out the need for power injection on your mini trees.

What you have posted in the link seems to not be a pixel but a Dumb RGB string , I cant see no chip references or chips actually on the pcb, so I doubt that there would be a 5v version of them anyway.
 

angus40

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Mike said:
These lights are very bright comapred to the standard LED's so for that size tree I should imagine 100 would be plenty.

Why not make your own mini trees? They are simple enough to do. Its basically a tomato cage modified to suit. Bunnings has them in various sizes.
Just do one and try it out, see if you like it

I disagree with Angus though on the 5v versions. Reason for this is you will be able to run more lights off the 12v than on the 5v due to voltage drop, possibly cancelling out the need for power injection on your mini trees.

What you have posted in the link seems to not be a pixel but a Dumb RGB string , I cant see no chip references or chips actually on the pcb, so I doubt that there would be a 5v version of them anyway.

Here mike , try these :)

as i said look at 5v .... much better !
also read the op's thread care fully , he asked about DUMB RGB .
http://www.diyledexpress.com/index.php?main_page=product_info&cPath=10&products_id=65
 

angus40

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np mike , i am cheap like scrooge when it come to shelling out for power .

even 50 count of these is bright .

Cheers
 

Mike

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These are definitely bright. But the 12v and 5v ones I have here are the same brightness. Just different input power.

Just because something is lower voltage dont mean that it has a low power consumption though. Its a very common misconception with low voltage lighting.

Most of these strings use 0.3w LED's
Based on ohms law the 5v ones will draw .06amp each LED on full white , 50 string = 3amp draw
the 12v ones will draw 0.25amp per LED on full white. 50 string = 1.25amp draw
Even though the same figure of 15w per 50 string remains , the current draw will not be as much with the 12v compared to the 5v.
So your still getting charged for the same amount of power, but the amp draw changes with the voltage.
What you are doing though is potentially maxing out the amp rating of your controllers much faster and not be able to use the board to its full potential.
Also voltage drops much much faster in 5v than 12v. Sometimes eliminating the need to inject power depending on the way things are set up, also the LEDs used.
Thats my opinion on it anyway.
 

Brettus

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Wasn't considering the voltage drop and the need for injection when i went with decided on the 12v leds. It was purely for the fact that i was going to use ray wu's 27 channel controler and i read somewhere that it doesnt go lower then 7v, making the 5v ones no good.
Thanks for the advise too.
 

Christmas on Clarafield

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It depends on what kinda of look you want from your mini trees. I just got my frames from Christmas Creations this week and have started to play. I do like the frames and my original idea was to have the old 200 LED strings in RGBW but I have decided to go with RGB strip. I have just posted some pics on my website http://christmasonclarafield.weebly.com/behind-the-scenes.html with these frames and 5m of RGB strip from ray.These strips are 12v so you can use rays 27ch controller. I did consider the RGB strings but with these frames you will need at least 100 RGB lights although I would imagine that probably 150+ would look better (but I dont have that many yet)
 

DougieB

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On the ones I did last year I had 4 strings 150 leds and they looked very full. On the 4 new ones I have, I am going RGB and was looking at 2-3 strings of 50. I was thinking strip as per pipers but she who must be obeyed wasn't really fussed with the look.
I would use 100 as a minimum
 

AussiePhil

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Mike said:
These are definitely bright. But the 12v and 5v ones I have here are the same brightness. Just different input power.

Just because something is lower voltage dont mean that it has a low power consumption though. Its a very common misconception with low voltage lighting.

Most of these strings use 0.3w LED's
Based on ohms law the 5v ones will draw .06amp each LED on full white , 50 string = 3amp draw
the 12v ones will draw 0.25amp per LED on full white. 50 string = 1.25amp draw
Even though the same figure of 15w per 50 string remains , the current draw will not be as much with the 12v compared to the 5v.
So your still getting charged for the same amount of power, but the amp draw changes with the voltage.
What you are doing though is potentially maxing out the amp rating of your controllers much faster and not be able to use the board to its full potential.
Also voltage drops much much faster in 5v than 12v. Sometimes eliminating the need to inject power depending on the way things are set up, also the LEDs used.
Thats my opinion on it anyway.

Mike,


A very common mis-understanding and i wish i had some handy to measure, the 0.3W thing should be taken with a gain of salt.


LED's are require a current value "x" to be a certain brightness, the current value "x" is independent of voltage.


"x" can be achieved either by a constant current IC like a 2801 OR by using a resistor to control the current based on the expected voltage.
What's this mean in real life.... assuming the friendly chinese company has set the resistor value correct to the expected 20mA / Colour a single RGB node set to white will draw 60mA with 100 nodes drawing 6A regardless of 5v or 12v.


Now 12v will allow for a greater voltage drop along the cable before any visible effects are evident but will have greater heat generated AND are less power efficient than the 5V version.


Cheers
Phil
 

Brettus

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Just trying to understand the draw of these units. If there specification say that each LED are 0.3watt draw and i was going to get strings of 100 at 12volts, wouldnt that mean that each 100 string would be 30 watts which at 12volts would 2.5amp.

The other thing is that their being three different circuits on these lights wouldnt that mean that the 2.5amps is spread across each colour???
 

David_AVD

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What Phil was alluding to was that the 0.3W figure often bandied about can be wrong. The 5V and 12V dumb RGB pixels are usually rated at 20mA per colour per LED.

So this means a 5V version will be 0.02A (current) x 5V (voltage) x 3 (colours) = 0.3W per LED. A 12V version will be 0.02A (current) x 12V (voltage) x 3 (colours) = 0.72W per LED.

In both bases the current draw per LED is 60mA when white. That translates into a higher power consumption (wattage) for the 12V ones, despite the current draw and brightness being the same.

So.... a 12V 100 count string would be 0.02A x 12V x 3 colours x 100 pixels = 72 Watts. (12V @ 6 Amps)
 

richardd

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I have the frames from Christmas creations and have a string of 12v 100 RGB's and it looks ok not as full as I would like be for now it will have to do. Since I have 8 trees looking at the math, I will only be able 4.86 trees with one of the 27ch controller and a 350 watt psu is that correct? How would the psu "feel" if I put 5 stings on of the board? I guess it would be just better to have 4 on one board with their own PSU and 4 on another board to achieve the best look.
 
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