1. New to Christmas lighting? Get started with the AusChristmasLighting 101 Manual:

24 FT long Matrix Alphapix 16 problem

Discussion in 'DMX, E1.31 & Networking' started by bhosted, Nov 9, 2015.

  1. bhosted

    bhosted New Elf

    Oct 14, 2015
    Likes Received:
    St. Marys Georgia USA
    My brothers, a short story. I have built a matrix using strips of 12v 30/10 ws2811 and one alphapix 16. The matrix is 21x100 or about 7 ft tall and 24 ft long. There are 9 universes all have 252 pixels in them except the last one which only has 84. for a total of 2100 pixels or 6300 RGB. I am using a 1500 watt gold rated computer power supply that has 6 PCI express outputs. Each outputs has a rating of 30amps continuous. I have injected power on every 3rd strip. the number 1,13,25,37,49,61,73,85,97 universes power and data cable go back to the controller. When I power everything up and use the test built into the controller every light, strip and pixel works great. When I test in xlights I get some universes that don't come on, some pixels are slow even colors that are not part of the test pattern. The Alphapix is version 1.03. I will include pictures of the controller setup the xlights setup and one of the power distribution panel I have created. Also the longest cable used to inject power is no more them 30ft and I am using 16/2 for everything going out to the controller.
  2. battle79

    battle79 Full Time Elf Generous Elf

    Dec 8, 2012
    Likes Received:
    Chirnside Park, Victoria, AU
    Going to guess you have a power problem.

    Looking at your power supply you have 1500W. 1500 / 12V =125A. It may do up to 30A on each of the 6 outputs but not all at the same time. (Also note the PS in the photo is only 1350W, so only 112A)

    2100 pixels = 210mtr of strip

    1mtr of strip = 0.64A (based on reference of current draws sticky'd under pixel forum)

    therefore 2100 pixels = 134.4A when full white.

    when your matrix is only doing one color it will work fine. When it tries to mix all three colors to make white, your going to have issues. Firstly it won't light up full brightness, and more importantly as your noticing, the drop in voltage on the positive, and the rise in ground reference will not allow for pixel data to be read properly by ICs.

    Also best practice is to not load a power supply more than 80% of its total load.

    I would recommend using a smaller PS to run the last few rows of the matrix to fix PS issue.
    I would also suggest that the Power injection cabling may need to be doubled up on any run over 5 mtrs, as that's not very thick cable if it's 16/0.20 as i'm assuming.

    Hopefully that fixes your problems.

    Still heaps of time till Xmas, I haven't even started putting anything up yet. Think I should panicking but I'm actually pretty relaxed.

  3. lizardking


    Dec 26, 2014
    Likes Received:
    Gold Coast
    Find Me On:
    so you have 7ft long strips injecting every 3rd strip how many pixlels per strip and what size wire did you use for the long runs of power injection

Share This Page