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Thread: Fuse and Power Safety Question

  1. #1
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    Default Fuse and Power Safety Question

    First year with my setup/show. I have 250 12V pixels attached to Falcon PiCaps (three of them, each with their own Raspberry Pi). For each 250, all connected together, I am running all three wires(power and data) to pixel #1. Then I power inject at pixel #250. For the power wire from the controller to pixel #1, am I at risk of pulling 15A? (ie 250 * .06). For the wire from the PSU to the controller, also at risk of pulling 15A? I have 14 AWG wire from the PSU to the controller. So 15A is max. But the wire from the controller to pixel #1 is 18AWG. I assume I should fuse with a 15A fuse between PSU and controller.

  2. #2
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    Default Re: Fuse and Power Safety Question

    I just run data only from the PiCap. Run your pixels directly off of the power supply with 15 amp capable wire. I do not run fuses on the pixels. But I do carry a heavy AWG wire to my next injection point (the small AWG pixel wires will drop the voltage). Just make sure the pi gnd and the pixel gnd are on the same pwr supply gnd. I only run 22 awg to the Pi.

  3. #3
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    Default Re: Fuse and Power Safety Question

    Quote Originally Posted by aknflyer View Post
    I just run data only from the PiCap. Run your pixels directly off of the power supply with 15 amp capable wire. I do not run fuses on the pixels. But I do carry a heavy AWG wire to my next injection point (the small AWG pixel wires will drop the voltage). Just make sure the pi gnd and the pixel gnd are on the same pwr supply gnd. I only run 22 awg to the Pi.
    I agree with everything up to the gnd statement. You need to run heavy gauge V+ and V- from the PSU to your injection points. You then run light guage V- and data (two wires together) from the controller to the first pixel. In additin, tying the V- together at the PSU gets you nothing and is a waste of time and effort.


    2021 New Tune-to sign. New 40x27 matrix at the house. Retiring the Strip based matrix. Updating some of the old window frames to the new house. Adding two new songs.
    2020 Full sized show reworked for the new location. Only adding (famous last words) 13 RBLs that I finally got converted to using pixels
    2019 - Just moved into a new home (yet another change of plans). Will be dim but not dark. Too much to do at the new place to leave time for a show. Dim show (3000 pixels) had regular visits most nights.
    https://www.youtube.com/user/MartinMueller2003

  4. #4
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    Default Re: Fuse and Power Safety Question

    Yes, you are at risk of pulling 15A for the first 250 pixels. I would suggest power injection at a lesser number of pixels, like 100. You will likely see a significant voltage drop (and resulting performance loss) from the thinner pixel string wire. And I would invest in some type of fuse device. Although not a PiCap setup, you can see in the photo how I fuse/power inject from the power supply.
    20210104_100757.jpg
    Kevin

  5. #5
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    Default Re: Fuse and Power Safety Question

    Quote Originally Posted by kev View Post
    Yes, you are at risk of pulling 15A for the first 250 pixels. I would suggest power injection at a lesser number of pixels, like 100. You will likely see a significant voltage drop (and resulting performance loss) from the thinner pixel string wire. And I would invest in some type of fuse device. Although not a PiCap setup, you can see in the photo how I fuse/power inject from the power supply.
    20210104_100757.jpg
    Thanks! The white wire I see coming from your controller, it looks like you hooked up data, ground and power. Is that right? How many pixels are hooked up to that controller?


    Sent from my iPhone using Tapatalk

  6. #6
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    Default Re: Fuse and Power Safety Question

    Yes, the white cable provides power and data to the first pixel. The first green lead feeds the ESPixelstick and then the other green leads from the fuse boards provide power injection to every 100 pixels. This ESPixelstick controls 645 pixels spread over three tall mini trees. The last fuse board output is for the enclosure cooling fan.
    Some people only send data and ground from their controller but I send +V too because the board is designed to provide power to the pixel string. You just have to inject when necessary.
    Kevin

  7. #7
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    Default Re: Fuse and Power Safety Question

    Quote Originally Posted by kev View Post
    Yes, the white cable provides power and data to the first pixel. The first green lead feeds the ESPixelstick and then the other green leads from the fuse boards provide power injection to every 100 pixels. This ESPixelstick controls 645 pixels spread over three tall mini trees. The last fuse board output is for the enclosure cooling fan.
    Some people only send data and ground from their controller but I send +V too because the board is designed to provide power to the pixel string. You just have to inject when necessary.
    Thanks! Mine is similar. I am only setting up 250 Pixels, and my controller(a PiCap) can also provide power to the first pixel. I bought some pops power fan out boards, which I will use to inject (either at 100 Pixels or at the end, at 250). My question is this: since the controller has 250 pixels connected to it, do they try to draw 15A, or do they not because I am injecting at 100 or 250?

  8. #8
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    Default Re: Fuse and Power Safety Question

    It will split the current. Connecting power at #1 & #250 may cause you to run lights @ 80% or 70%, but that is not normally noticeable. I have done that to reduce injection points.

    If you say 15A load and you split with 2 power points 1-#1 & 1-#250. Each power point is 7.5A
    Fuse each lead @ (7.5A x 1.25 then round up to next fuse size) 10A a side.
    You will have potential to carry 25A-30A on your pixel wire, but hopefully your wire is rated at 105C and it will carry that current long enough for the 10A fuses to open. One will blow then the second will blow.
    In Lights Therapy

  9. #9
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    Default Re: Fuse and Power Safety Question

    Quote Originally Posted by MartinMueller2003 View Post
    I agree with everything up to the gnd statement. You need to run heavy gauge V+ and V- from the PSU to your injection points. You then run light guage V- and data (two wires together) from the controller to the first pixel. In additin, tying the V- together at the PSU gets you nothing and is a waste of time and effort.
    I think you misunderstood what I was saying. Just 22 awg to the controller. " You need to run heavy gauge V+ and V- from the PSU to your injection points" the controller minus and pixel minus do need to be common.

  10. #10
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    Default Re: Fuse and Power Safety Question

    Quote Originally Posted by aknflyer View Post
    the controller minus and pixel minus do need to be common.
    Not at the PSU. They need to be common at the pixel. When running your 22AWG Data and V- from the controller to the first pixel, The controller V- and the PSU V- and the pixel V- get tied together. It is important that the V- wire from the controller goes to that first pixel and it is unimportant that there is a V- wire between the controllers PSU and the pixels PSU. This is true even if you are only using a single PSU. Many people (not all) have encountered flickering when they ignore this recommendation.


    2021 New Tune-to sign. New 40x27 matrix at the house. Retiring the Strip based matrix. Updating some of the old window frames to the new house. Adding two new songs.
    2020 Full sized show reworked for the new location. Only adding (famous last words) 13 RBLs that I finally got converted to using pixels
    2019 - Just moved into a new home (yet another change of plans). Will be dim but not dark. Too much to do at the new place to leave time for a show. Dim show (3000 pixels) had regular visits most nights.
    https://www.youtube.com/user/MartinMueller2003

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