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Wiring - Beginner.

Discussion in 'Computers, Cabling & Other Miscellaneous Hardware' started by klaus, Nov 25, 2014.

  1. klaus

    klaus New Elf

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    I have just received my 30 metres of LED Strips which are 12V 5050 -60- WS2811. They use 14.4W per metre. I have attached them to 25mm conduit and will be attaching that below the guttering. My question is in relation to the wiring and the best way to connect to the LED strips and size. I will need approx 100m of wiring in total with 19 metres being the longest distance between a power source and Strip. The LED's are a 3 Wire setup so I was thinking of running 3 core 1.5mm flat insulated wire back to the garage where the 4 Power Supply Units and Basic LED Controller will be. There are 7 Sections/Channels with 10 strips in total.
    I have attached a layout to help visualise what I am trying to do.


    My Questions is: Is the 1.5mm wire good enough to go the distances I require so I don't lose voltage/signal etc and have I forgotten anything.


    Thanks in advance!


    Klaus.
     

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  2. BundyRoy

    BundyRoy Senior Elf

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    Klaus, as long as you can get the power to the end of the strip with limited voltage drop you should be able to run 2 strips joined together before you need to connect power to the following strip. It would be easier to help with the voltage drop calculations if we had a list containing, distance from PSU and length of strip run in each section.

    The other thing you will need to think about is you will need a null pixel every 3-5m in the cable between the controller and the start of the pixel strips and also between strips if they are connected with more than 5m of cable in between.

    What controller are you using? You may find that the current draw of the strip is more than the controller can handle. This is fine but it means that the strip needs to be powered straight from the PSU not through the controller.
     
  3. OP
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    klaus

    klaus New Elf

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    BundyRoy. I have a 8 output Amplifier connected to my controller for signal but yep I will have to connect each led strip to a PSU. The lengths of the strips are in the Layout Pic I put on the post(I hoped it worked). The distances I have gauged are:
    17 m to A (3m strip)
    19 m to B and B1 (5.2m strip -3.2m & 2m)
    10 m to C (3.4m strip)
    10 m to D (5m Strip)
    11 m to E (2 x 2.5m strips)
    5m to F (2 x 2.5 m strips)
    16m to G (3.4m strip)


    And here comes the novice in me. What is a null pixel. I've heard about them just no idea what it is.


    Cheers Klaus.
     
  4. BundyRoy

    BundyRoy Senior Elf

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    No such thing as a dumb question Klaus. The only mistake you can make is not asking the question. A null pixel is just a normal pixel in a cable between the controller and the pixels you want to light up. A null pixel is in the cable and you tell your controller in its settings how many you have and then it adds these null pixels to the sequence data so that they never get turned on, they just pass the signal down the cable.

    The reason for a null pixel is that after about 5m or so the strength of the data signal in the cable gets too weak to work. Putting the signal through a pixel regenerates the signal strength and it can go another 5m or so (depends on interference and surrounding materials etc) and repeat this till you get to the pixels you want to turn on. The null pixel needs to be the same protocol (ws2811) so it can pass on the signal. Hope this makes sense.

    If you have a signal amplifier then you may not need any null pixels though. Others will have to chime in here as I have never used an amplifier. This is only my first year. Not sure how far you can go with an amplifier.

    In terms of calculating your voltage drop. I would start here. http://www.da-share.com/calculators/

    Go to the led current section first and select your type of strip and the strip lengths. This will give you the current draw of each strip.

    Then go to the cable voltage drop section and select your wire size, wire length (remember the wire length is the return distance from PSU to strip, not just one way) and your calculated current draw. This will then give you voltage drop in each cable.

    I have not done roof lines yet, so I'm guessing there are many tricks to save cable. Hopefully other will chime in. My guess is maybe run a thicker cable for the main distance from PSU to roof. Then branch out from this one cable with smaller cables to each of the strips on the same PSU if possible.

    Also remember if you have cheap PSU's then you don't want to use more than 60-70% of their rated wattage to prevent them overheating. I think it is okay to use higher loads on the good quality meanwell PSUs.

    Hopefully this will get you started. I am by no means an expert.
     
  5. OP
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    klaus

    klaus New Elf

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    Thanks great info.
     

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