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Thread: Anyone able to test some LED strings?

  1. #31
    Join Date
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    Default Re: Anyone able to test some LED strings?

    Quote Originally Posted by fj View Post
    i just want to say a big thanks to yourself, aussiephil and aususer for helping me out on this !!
    Glad I could help.

  2. #32
    Join Date
    Dec 2007
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    Canberra, ACT, Australia
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    Default Re: Anyone able to test some LED strings?

    Quote Originally Posted by aussiephil View Post
    fj

    Hi, package arrived this morning, not long home and just had to play.

    Initial impression is build quality is good.

    Had to pull the little box apart that is on the cable, it contains a bridge rectifier so if you wish to run these from a AC SSR then they are full rectified.

    The bridge is a KBP210 a 1000v 2A unit that is no doubt used across all their voltage options.

    Powered up the pink/purple ones, what a great colour. That's as far as i have got, plan to measure voltages and count led's per section etc over the next few days.

    As always Left to Right.
    1. Bridge rectifier covered in what seems like some sort of hot melt glue.
    2. Took quite some effort to cut away and lever this up so i could get a model number.
    3. purple set powered up

    if i was going to use these with the rectifier in place i would undo the four screws and just run a bead of silicon around and screw the cover back to ensure it's completely waterproof.

    Cheers
    Aussiephil
    Here's what i have and think.

    I had Purple and Red Strings

    Both strings are 10 leds per section with 10 sections per string.
    Resistors used for current limiting were different indicating thought went into forward voltage differences.
    At 200mA per string...
    Purple is visually not that bright and is backed up by LUX readings and has a very incandescant look.
    Red is somewhat brighter visually (2x measured at the same total current)

    At around 350mA (quite overdriven) both sets start to approach the brightness of the Big-W strings from last year, visually at least at the same voltage. The 120 count Big-W string was drawing less than 80mA though.

    I have the purple string next to my custom RGB string and yes the RGB string blows it away for brightness but the purple string is not lost and would still look good in a display.

    Fading is actually very smooth on the Tiger controller with a visual variance visible from DMX levels 10-225.

    I haven't had a chance to throw them outside under rain yet but they look like they would be fine.

    Dislikes:
    One section of the purple string had a weird resistor value and is a little duller.
    Significant difference (3v) between the strings for nominal 20mA/200mA current.
    Only about half the visual brightness of a Big W string. This can be a positive if looking for a softer look.
    The purple string is overdriven at 24v DC.
    Removing the full wave bridge will make the overdrive issue even worse if you cut these into shorter sections

    Conclusion:
    Overall mechanical construction is good with decent wire and insulation thickness, however the poor resistor choices that lead to the differences in current /Vf indicates to me a desire to get it right but not keeping quality checks going all the time.

    value wise - at $6-$8 a string they are not to bad, easy to work with, cuttable every ten leds and at least for full strings no polarity concerns, they also have a consistant spacing for the LED's.

    If i was looking to buy more lights this year i would likely order some.

    Hope this helps in some way.
    Cheers
    Aussiephil
    2012:
    Software: LightFactory Personal
    Hardware: J1Sys Pixel controllers . [url]Http://www.j1sys.com[/url]
    Lights: 6000+ Pixels and 20k+ LEDs
    Channels: around 20,000 channels

    You know where to find me....

  3. #33
    Join Date
    Dec 2007
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    Melbourne, Australia
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    Default Re: Anyone able to test some LED strings?

    hi aussiephil,

    thanks very much for your review, i really appreciate it.

    is 200mA per string normal or acceptable? that means only 5 strings per amp and i thought LED's were much more efficient than that or am i getting this totally wrong?

    i'll let them know about the different resistor used in one section of the purple string to make sure they are aware of it.

    thanks, fj

  4. #34
    Join Date
    Dec 2007
    Location
    Canberra, ACT, Australia
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    Default Re: Anyone able to test some LED strings?

    Quote Originally Posted by fj View Post
    hi aussiephil,

    is 200mA per string normal or acceptable? that means only 5 strings per amp and i thought LED's were much more efficient than that or am i getting this totally wrong?

    thanks, fj
    Leds are more efficient, however for low voltage use the difference will be less than our friends in the USA see at 120v.

    Each series section of leds should have a nominal 20mA of current..
    So
    12v = 3 leds is the normal regardless of colour
    24v = 6 to 10 leds depending on Vf of the colours
    110v = 35-50 again depending on Vf of the colours

    Calculating nominal string current is as easy as counting the number of sections and multiplying by 20mA.
    So for the ones you sent me they had 10 sections so 200mA is exactly expected.

    A Big-W white string is also 10leds per section with 12 sections for nominal current of 240mA
    A big-W red string as 15leds per section for 8 sections and a nominal current of 160mA.

    Why do i use the word "nominal", because it is purely a calculated starting point. As all these strings either use resistors or have a higher Vf (more leds) than their rated voltage the ACTUAL current will need to be measured for you specific operating voltage.

    As you could see when i ran the purple at my usual 27v they drew 350mA.

    hope that made sense....
    Cheers
    Aussiephil
    2012:
    Software: LightFactory Personal
    Hardware: J1Sys Pixel controllers . [url]Http://www.j1sys.com[/url]
    Lights: 6000+ Pixels and 20k+ LEDs
    Channels: around 20,000 channels

    You know where to find me....

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