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Have I messed up?

Discussion in 'Power Supplies' started by moogle, Nov 2, 2017.

  1. moogle

    moogle New Elf

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    Hi all,

    I'm currently building a setup using 40 meters of ws2812b 5v pixel strip which has 60leds/m they draw roughly 14w/m. Now I've built a rack mount that houses two 60A power supplies plus network switch and pixlite controller. This is going to me mounted under a stage desk and the plan is to inject power every 2 meters into the installation.

    I have 4 lines going out to the strip and then 20 power injection points. Now the cables I've ordered from ray wu (and received) are 3 meter 2 core cables with waterproof connectors which look to be about 1.5mm2. Now I'm freaking out that these cables aren't going to be sufficient enough to power the lighting display and I've just prewired the whole rack mount with 2 pin plugs and don't have enough time before next Saturday to re-wire everything!

    I need some assistance in the best way to calculate where I currently stand with power consumption I'm a bit lost and with the size of this rig it's the first time I've had to worry about cable sizing.

    Any info is greatly appreciated! Thanks.
     
  2. AAH

    AAH I love blinky lights :) Community Project Designer

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    You shouldn't need to break strips up so injecting at the 4m or 5m intervals should be fine.
    The cable is probably either 0.75mm2 or 1mm2, it should be imprinted onto the cable itself.
    The voltage drop should be limited to about 10% so that no pinkening occurs. There's a calculator that I put in the ACL 101 (I think) that should allow you to calculate it. It's hard to give any advice without knowing cable distances and sizes though. If you draw up a sketch of how things connect and check to see if the cables are marked then better advice can be given.
     
  3. scamper

    scamper Senior Elf

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    Like Alan said it is a bit hard without seeing exactly how you are doing it, but if you are running that much power injection and each cable is going back to a power supply, then the load is spread very lightly across each one, so it shouldn't be a problem, If you were running them in a serial connection, then you may have problems.
     
  4. OP
    OP
    moogle

    moogle New Elf

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    So I've had a look on Ray wu's website the cable is 0.75mm2. This is an image of the stage layout. There are 40 pieces of led strip all at 1m each in length. The led's are split into 4 runs of leds at 10m each. Each of these 4 led runs have power injection every 2m of LED strip. So a total of 24 injection points (the 24 includes the 4 power connections at the start which also have the data signal in the 3 core cable). This is all fed by 3m long power injection cables to T pieces in-between the strips. (0.75mm2) back to the rack mount control unit. Inside the rack mount are two Meanwell 60A power supplies. Is there anymore info I need to work it out?
     

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  5. scamper

    scamper Senior Elf

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    So if each of the power injection leads are going back to the power supply, then it should be fine.
     
  6. fasteddy

    fasteddy I have C.L.A.P Global Moderator Generous Elf

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    So if the strip is 14.4 watts per meter and you have 40 metres then the total max wattage of the installation should be approx. 576 watts which is approx. 115 amps @ 5vdc
    When using 2 x 60 amp power supplies then it will be very important on the brand of power supply you are using because if you are using a cheap Chinese brand instead of Meanwells then you may come into some load issues because it is recommended to only run the cheap Chinese power supplies to 80-85% of their total load rating. Personally I would be using 450 watt power supplies for this installation so you don't drive your power supplies too hard, or else don't use any white for your effects as that will be where you maximum current draw will occur.
     
  7. OP
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    moogle

    moogle New Elf

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    I'm using two 300W Meanwell's and probably going to restrict the LED outputs to about 80% in the advatek assistant client. I'm more worried about the power injection leads are not a suitable size.
     
  8. Boof63

    Boof63 Senior Elf Generous Elf

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    Consider brightness even at lower %, you will find some effects , butterfly- will wash out at higher brightness, but lower % makes them work much more effectively and look more like the preview in XL. i run my megatree and matrices at around 40-50 %, plenty bright enough for cars 25-35 m away
    Cheers Boof63
     
  9. djgra79

    djgra79 Senior Elf Generous Elf

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    Look forward to seeing some pictures or video of the stage/display once up and running!
     

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