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Power question for mega tree

Discussion in 'Power Supplies' started by Stkilda123, Apr 17, 2019.

  1. Stkilda123

    Stkilda123 New Elf

    Mar 19, 2019
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    Hi, sorry if this is a dumb question but just trying to start this year from ordinary lights to programmable ws2811, and i've spent many hours trying to learn, but still have questions.

    I've purchased a F48 with 4 x 4 string differential boards, which i plan to use for a 16 string x 100 pixel ws2811 (12v).
    I've read that each pixel is .66 watts each, so my numbers say that 4 strings of 100 pixels attached to each board would be 264 watts at 22 amps. I read that the differential board can take 30 amps,
    So my question is if i attach a 30A (12v) power supply to the board, will it be able to run all 4 strings of 100 pixels without me needing to inject power?
    And that would mean that i would need 4 x 30A power supply's to power my 16 string mega tree?
    I would appreciate any advice,
    Thanks, Michael
  2. AAH

    AAH I love blinky lights :) Community Project Designer

    Dec 27, 2010
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    The need to power inject is due to voltage drop which is a function of the number of pixels, the distance and the gauge of the wire.
    If your power supply and diff boards are immediately adjacent to the base of the tree then most of your battle is won.
    The figures quoted on Aliexpress etc aren't always anywhere near accurate. I use the WS2811 spec which is 18.5mA/colour per pixel so that gives you 55.5mA per pixel. The 0.66W is pretty close but that number won't be listed the same across all 2811 pixels.
    If you use a 12V 360W supply you can power 540 pixels max. If you use a string of 100 on each of the 4 outputs of diff board then you should be good.
    If you want to preserve outputs of the F48 and diff board then instead of using 100 pixels per output then if you use more and use something like my Power8 power distribution board then you can hook up 2 power supplies to it and therefore power twice as many pixels from 1 pixel output.
    ezellner likes this.
  3. uncledan

    uncledan Full Time Elf

    Dec 27, 2014
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    Buellton California
    Very few of us run at 100% intensity. Most of my 12v nodes were 55ma +/- at 100% intensity white. At 30% intensity white the average was 20ma +/- per node. I have 1,000+ pixels on a Meanwell RSP320-12 and its loaded 50% or less when the show is running. I've had 200 pixels powered through the Falcon with no power injection or problems. 100 12v nodes shouldn't need any power injection unless they have small wire. I order everything with 18AWG to minimize voltage drop.

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