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Thread: 75 pixels using 5V is working... am I crazy?

  1. #1
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    Default 75 pixels using 5V is working... am I crazy?

    Let me start this off by saying that I've been around these forums and pixels for a very long time and I'm not looking to start a battle between 5V and 12V, this is just a simple exploratory question...

    Some Background: After 5 years in service, we decided to switch up our approach to our megatree after this past season. When we originally set it up, there were no HDPE pixel strips... only people affixing flex pixel strip or individual pixels to things like strapping, conduit, steel cable, etc... we went with 20' lengths of 3/4" PVC conduit pipe. It obviously wasn't too bad or we wouldn't have kept it going like that for 5 years... but it required us to use a flat back square pixel node that I think caused many issues for us being here in Florida with humidity and rain at Christmas. Almost every year I would have at least one dead pixel in 1/4th of our strings. As the years have gone on, it seems that almost everybody is using pixel strips with pixels punched through. I am now interested in moving our display in that direction.

    So, I am a 5-volt'er. The majority of our display is 5V. Only the roof is 12V because we use Technicolor and they were originally only available in 12V. Our megatree in the past has consisted of 48 x 50 strings running off a single F16V2 + Expansion. It is a 20' tall pipe and we were running roughly 4.5" spacing between pixels (we zip tied them to 3/4" PVC so I could set the spacing at whatever I wanted). That would get us around 19' of lighted length on the megatree leg, which is fine. We don't need to go all the way to the bottom since our ring is 16" off the ground and we have 48 mini trees around the base of the megatree.

    I know many of the megatrees that I have seen are 12V and consist of over 100 pixels running at 2" spacing... They look AMAZING, but I can't seem to be able to get myself to go that crazy. We have over 20,000 other pixels including four large window matrix units, so I don't need to use the megatree for graphics... the 2" spacing on the window matrix units does a good job of that. I am thinking about going to 3" spacing on the megatree and I wanted to see how far I could push 5V lights now that it is so common to use 50% or less for the output intensity out of the Falcon controllers. I ordered some lights from Ray that were 60, 65, 70, and 75 lights long with 8.0cm and 8.5 spacing (3.14" and 3.34")... I thought for sure that there was no way the 75 count would work... but it did... so what does "work" mean? Well I have them running at 50% output intensity and there is ZERO noticeable difference in white between pixel #1 and pixel #75. I measured the voltage after pixel #75 and it is around 3.65V. The current draw for the 75 lights is around 1.15 amps to 1.20 amps running the white fade test sequence in FPP.

    So does anybody else do this with 5V lights? I tried it once with 65 lights in my bushes, but those were 6" spacing between pixels and I think the pixel string length just got too long resulting in heavy pink-ing of the lights at the end...

    75 lights at 3.0" spacing is equal to the same height as 50 lights 4.5" spacing... so I wouldn't be losing anything in height... Since I have room on the Falcon... I would probably set it up to run 60 or 64 strings... I have to see what megatree rings are available out there... 5V x 1.2 amps is 6 watts which is only 360 watts to 384 watts total... and I have dual Meanwell 350 watt power supplies in that case...

    Thoughts?

    Thanks,

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  3. #2
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    Default Re: 75 pixels using 5V is working... am I crazy?

    the issue is current per inch, 50 pixels at 1 inch spacing works great. 50 pixels at 10 inch spacing may fail.


    2018 - Moving and going to visit my Daughter in New Zealand. Most likely I will be dark or nearly dark, Some static stuff that is simple to put up.

  4. #3
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    Default Re: 75 pixels using 5V is working... am I crazy?

    I go off of results not what others say can or cant be done. If it works at 50% on white go with it. Very rarely if ever will the tree be all white. I tend to push the limits on my 12v stuff. 48x110 tree powered only at the bottom and I can run at 100% intensity(I don't, run at 40%). My fence along the perimeter worked flawlessly with 300+ pixels at 20% intensity. I powered from both ends anyways but it was doable from one end. If it works, it works. I've also found that pixels from different orders react to voltage drop differently, even though they should be the same

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  6. #4
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    Default Re: 75 pixels using 5V is working... am I crazy?

    I have a 30x100 mega tree with 5v pixels running at 40%. I have it configured as 15x200 strings with power at the beginning and end. I had originally planned to inject at 50 (halfway up the tree) but when I tested my setup I could not tell a difference with my current setup. I run my whole tree plus 270 node star (3270 total) on two 350w power supplies.

  7. #5
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    Default Re: 75 pixels using 5V is working... am I crazy?

    Quote Originally Posted by uncledan View Post
    I go off of results not what others say can or cant be done. If it works at 50% on white go with it. Very rarely if ever will the tree be all white. I tend to push the limits on my 12v stuff. 48x110 tree powered only at the bottom and I can run at 100% intensity(I don't, run at 40%). My fence along the perimeter worked flawlessly with 300+ pixels at 20% intensity. I powered from both ends anyways but it was doable from one end. If it works, it works. I've also found that pixels from different orders react to voltage drop differently, even though they should be the same
    100 % agree with this reply . If it works go with it !

  8. #6
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    Default Re: 75 pixels using 5V is working... am I crazy?

    My advice would always be to do the appropriate math. Make sure you're not exceeding the limits of your power supply, wire gauge and distance. What might work in testing could overheat when used for longer periods of time. To save myself the trouble of going over the math, there's a useful calculator that would help you determine how far you are within power limits. Based on that calculator, which I believe to be accurate, 75 pixels at 5v shouldn't be a problem.

  9. #7
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    Default Re: 75 pixels using 5V is working... am I crazy?

    Quote Originally Posted by dcamron View Post
    My advice would always be to do the appropriate math. Make sure you're not exceeding the limits of your power supply, wire gauge and distance. What might work in testing could overheat when used for longer periods of time. To save myself the trouble of going over the math, there's a useful calculator that would help you determine how far you are within power limits. Based on that calculator, which I believe to be accurate, 75 pixels at 5v shouldn't be a problem.
    Agreed. I would also like to add that you should never exceed 80% of the capacity of the PSU or the wire. Overheating is a condition that does not show up until a prop melts down or goes up in flames.


    2018 - Moving and going to visit my Daughter in New Zealand. Most likely I will be dark or nearly dark, Some static stuff that is simple to put up.

  10. #8
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    Default Re: 75 pixels using 5V is working... am I crazy?

    The truth is, and will always be...
    Whatever works for you!
    Live, Laugh, Love.

  11. #9
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    Default Re: 75 pixels using 5V is working... am I crazy?

    Ok thanks everybody! The individual outputs for the Falcon F16 are 3 amp or 5 amp I believe... and I will only be putting out 2.4 amps max from my measurements. I have eight (8) x 12 AWG stranded wires running from dual 350 watt power supplies which averages around 15 amps per line, which is safe.

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