I thought power injection only affected the end ...

Discussion in 'Computers, Cabling & Other Miscellaneous Hardware' started by OzAz, Mar 3, 2017.

  1. OzAz

    OzAz Full Time Elf

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    when I connect 2 * 5m 30/10 pixel strips together, with a short extension lead, the whole of the second strip is duller than the first.
    I thought lack or power (power injection required) was usually identified by just the last few pixels dull?


    Voltage measured under load:
    12.35V out of controller
    11.75V out of 1st strip
    9.75V at end of second strip


    Theoretically the controller and power supply is supposed to be able to power 2 * 5m strips in series.


    Any ideas, apart from power injecting into the end of the second strip?
     
  2. David_AVD

    David_AVD Good news, everyone!

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    Powering even a single 5m strip from one end can be iffy. You should not be powering 2 strips from just one end of one strip.
     
  3. Boof63

    Boof63 Full Time Elf

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    try power into the end of the 2nd string and see how you go.
    Normally i can get 3 strings 30/10 ws2811 , but i need pwr at start and end of third to cover everything in the middle (this is half of my ray tree 6 x 25 pix), thus pwr-////// -pwr-\\\\\\-pwr : //=strings)
    cheers Boof63
     
  4. fasteddy

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

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    You could just inject power in the middle of the 2 strips so you back feed the first strip with power and forward feed the second strip. But you must also make sure that the gauge of the cable is large enough for the current drawn from 2 strips.
    The voltage drop seen in a strip is determined by the quality and size of the tracks on the strip PCB and also the cable gauge used to connect the strips. The voltage also has a major influence as you will get away with less % of voltage drop using 12vdc as apposed to 5vdc
     
  5. the grinch

    the grinch I guess I could use a little social interaction

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    Yeah my experiences with 2811 12v strips not a problem with running 2 strips without power injection third needs bit more power always in my situation ! I am wondering about the distance or Guage of wire you are using to feed strips may be insufficient don't think you should be having troubles . generally with 12v strips the third strip will run fine but little fade at end .also have you tried other strips and swapping around you may have dodgy strip ! Or insufficient power supply ?
     
  6. i13

    i13 Senior Elf

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    I demonstrated two 12V 30 LED/metre strips end-to-end at the 2016 Adelaide mini and the start of the first one was connected almost straight to the power supply. Voltage drop made the colours show up incorrectly on the second strip, especially with full brightness white.
     

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