Underpowering an LED strip

Discussion in 'Home Cinema Buying & Building' started by wellsi, Jul 7, 2015.

  1. wellsi

    wellsi
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    Just after anyone's experience on under-powering LED strips. I have a 120w 24v transformer and would like to power a 10m 5050 RGB 24v strip that has 60 leds / m.

    Assuming 0.25w per LED, that's 600 x 0.25 = 150 watts. Will I ruin the LEDs if I only supply 120w? Having them a bit dim is fine. I'm assuming I can't overload the transformer as it will ony give out what it can.... but any advice welcome.

    Cheers
    Ian
     
  2. supraTTman

    supraTTman
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    Wrong assumption!!

    In theory, 2 off 60/m strips will need 14.4W/m x 10m = 144W running flat out = all R G & B LED's ON = bright white, so you are not far out on that score.

    Running a switched mode power supply higher than around 80% of its rating will reduce the lifetime as it is working quite hard even at 80%.

    So in theory you will need 144W/0.8 = 180W for good reliability.
     
  3. wellsi

    wellsi
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    Fair enough! Thanks for the advice!

    Cheers
    Ian
     
  4. Member 721023

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    I would also like to add a tip; usually more than 150 Watt chassis PSU will have a built-in fan and that will cause some noise that could be disturbing if installed in silent enviroment. For this reason I would suggest an enclosed switch mode PSU (IP67) not less than 180W as very correctly already suggested to you.
     
    Last edited: May 6, 2016
  5. supraTTman

    supraTTman
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    Good point Hiline, I have found with my several psu suppliers that the threshold between fan-less psu's and fanned psu's to be around 20A/12V = 240W or 10A/24V =240W same power factor.
     

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