Another 12V RGB+WW strip question...

Discussion in 'RGB Lights - Intelligent Pixels and 3-Channel RGB' started by nutz4lights, Jun 29, 2014.

  1. nutz4lights

    nutz4lights Full Time Elf

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    So, as I mentioned in another thread, I'm getting ready to do some interior RGB decorating and love the idea of the new(ish) RGB + Warm White dumb strips that are out on the market. Ray obviously has one and the other that I am considering is the Supernight brand sold on Amazon with free shipping.

    Here is the Amazon product:
    http://www.amazon.com/SUPERNIGHT-16-4ft-Lighting-Waterproof-Multi-colored/dp/B00K6ZJVP4/ref=sr_1_1?ie=UTF8&qid=1403967031&sr=8-1&keywords=rgbww

    Here is the Ray Wu product:
    http://www.aliexpress.com/store/product/5M-300-LEDs-60led-M-5050-RGBW-RGB-Warm-White-LED-Strip-Light-waterproof-in-silicon/701799_1844042119.html

    The question I have is... they are both 300 of the 5050 LEDs... they are both 120 degree spread, they are both 10mm wide strip, they are both 5 meters... everything seems to be identical... so why is the power draw on Ray's site listed as 6A and 72W power draw whereas the Supernight is listed as 5A and 60W.

    Any thoughts? I plan on ordering one of the Supernight products so I can measure power draw, but would rather not pay $20 shipping on a $20 strip from Ray just to find out they are the same.

    Thanks,

    -Louie
     
  2. Ɠαяєтн

    Ɠαяєтн Mae gen i C.L.A.P ei heintus iawn

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    Have a look at this


    http://electronics.stackexchange.com/questions/19413/why-doesnt-my-5050-led-strip-draw-as-much-power-as-i-expect


    Ray's I expect are using slightly different resistors in the strip and therefore may have a different power rating and may be brighter. I say "may" as the specs that are quoted are sometimes copied and pasted from other products, e.g. Ray's says power consumption is 11.52W/m, so 11.52W/m x 5m = 57.6W..........


    They look very similar products but the only true way is to compare side by side. If your concerned about the postage cost then I would try the ones from Amazon first t see if they suit your needs.
     
  3. scamper

    scamper Senior Elf

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    I agree, I looked at three different ones that all look the same.
    1 was 58w another was 60w and the third was 72w.
    I guess you will need to try them, or just pick 1 and if you are happy with it, stick with it just in case there is a variation in brightness/colour.
     
  4. OP
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    nutz4lights

    nutz4lights Full Time Elf

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    Excellent link, thanks. I have a bunch of experience with pixels and voltage drop, so it appears the same phenomenon is present with these strips... I have never worked with strips. I didn't see the 11.52 W/m the first time I looked... only the 72W rating... wonder which it is... I suppose it depends whether the warm white or RGB are lit...
     
  5. OP
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    nutz4lights

    nutz4lights Full Time Elf

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    ...and I guess I should add that if they operate like anything else in the RGB world that I've dealt with, I probably don't need nearly as big of a power supply as I think I do ;)

    -Louie
     
  6. fasteddy

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

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    Dont always trust Chinese vendor ratings, many times i have found these to be wrong due to the use of copy and paste.

    There are also a large variation in LED quality and resistor values used especially with the cheap budget strip as they generally use whats cheap and available.
     
  7. OP
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    nutz4lights

    nutz4lights Full Time Elf

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    Hey all,

    So I received some of the strip from the Amazon link above (although I ordered them off eBay). The Supernight brand rated at 60W. I just went out and completed some voltage-current testing and as others mentioned, the current values are much lower than the rated wattage. Measurements are for the full 5 meter strip.

    Current draw, full intensity:
    Warm White: 1.37A
    Green: 0.78A
    Red: 0.76A
    Blue: 0.71A

    Voltage at output of controller with warm white on: 12.33V
    Voltage at end of 5 meter strip with warm white on: 9.79V
    Voltage at end of 5 meter strip with blue on: 10.77V

    So this strip is only drawing around 14W, not 60W as stated in the specs.

    FYI.

    -Louie
     
  8. David_AVD

    David_AVD Good news, everyone!

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    How did you arrive at the 14W result?
     
  9. OP
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    nutz4lights

    nutz4lights Full Time Elf

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    I figured the average voltage was probably around 11V and 1.37A at that voltage is 14W, no?
     
  10. David_AVD

    David_AVD Good news, everyone!

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    The advertised wattage would be the sum of all colours, so 12V (input) x total current (1.37A + 0.78A + 0.76A + 0.71A) would be the way to go. This gives you around 44W.

    Did you measure the current with just one colour on at a time? If so, those values will drop some more f you have more than one colour active at a time. This is due to voltage in the common (V+) wire.
     
  11. OP
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    nutz4lights

    nutz4lights Full Time Elf

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    I understand what you're saying but you don't have a reason to turn all the colors on. This strip has a separate white LED and when I ran just that white LED I got the 1.37A value.
     
  12. David_AVD

    David_AVD Good news, everyone!

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    The wattage rating will still be the sum of all circuits ( colours) unless the seller specifically stated the wattage rating of them separately ?
     
  13. OP
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    nutz4lights

    nutz4lights Full Time Elf

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    I guess that's fair, but when I think about total wattage, I think about what you can turn on. For instance, even if the rating is not completely accurate, a normal RGB pixel might have a wattage draw of 0.3W (5V) or 0.6W (12V), right? That is if you turn all circuits on and produce white. So a string of 50 could theoretically draw 15W or 30W. I get that. These RGB+W strings don't have a need to be turned on like that, since they have a separate white line. I was thinking that would affect the rating value, but obviously my thinking was incorrect. At least we're addressing it here.

    They are 60 LED/meter, 30 of those are warm white and 30 are RGB. So, if you turn on warm white, you'd expect 30W and if you turn on all RGB lines, you'd expect 30W as well. I guess that makes sense, and I'm measuring 14W for warm white.

    -Louie
     

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