RGB String testing

Discussion in 'Lights - Store Bought and Home Made' started by AussiePhil, Jun 11, 2010.

  1. AussiePhil

    AussiePhil Dedicated Elf Administrator

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    Well my RGB strings arrived today.

    These are a classic string with all LED's being controlled together.

    They require a 5v DC power by default and came as 50 RGB LED strings.
    [smg id=32]
    Two 50 count strings straight out of the box

    The spacing between modules is 75mm or 3 inches, giving a 50 count string a overall length of 3.75M or 12 feet.
    [smg id=33]

    Each Module is about 12mm wide and a 8mm RGB 4pin LED is used.
    [smg id=34]

    looking at the wire end shows that whilst the outer silicon(plastic) module is closely molded to the wires they is no sealing between the two 4 wire groups, a quick injection of silicon sealant should work well, yet to test
    [smg id=35]

    ............ continued post 2
     
  2. OP
    OP
    AussiePhil

    AussiePhil Dedicated Elf Administrator

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    ...........continued

    I then connected them up to the bench top variable power supply with digital readouts so i could measure current draws

    [smg id=36]
    Here they are with Red connected

    [smg id=37]
    Green - the green is not a deep green that is often seen but a lighter green, still looks good

    [smg id=38]
    Blue - this was quite an intense blue, very nice

    Technical details

    These use 4 pin RGB LED's with common positive.
    This means that ALL individual modules are connected in parallel.
    The string has a nominal FIVE volt rating.

    Based on the nominal 20mA LED current draw for a single LED i would expect to see 1A per colour for 50 module string at 5V

    Current Measurements
    I measured current draw for three voltages 5v, 5.5v and 6v

    5 Volt
    Red: 790mA
    Grn: 810mA
    Blue: 910mA

    5.5 Volt
    Red: 900mA
    Grn: 990mA
    Blue: 1.1A

    6 Volt
    Red: 1.02A
    Grn: 1.16A
    Blue: 1.32A

    Based on the above measurements, at 5 volts the string is slightly under driven, 5.5v is just about right and 6v is slightly over voltage.

    Over the weekend i will hook up a TigerDMX48 and see how low i can take the supply voltage and then test these with it.

    Cheers
    Phil
     
  3. ThaiWay

    ThaiWay 1500 C9's are not green

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    Thanks for that Phil... they really look good!

    John
     
  4. Garrison

    Garrison New Elf

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    I am anxiously awaiting the results of your testing Phil! These would be ideal for outlining the roof line of my home.
     
  5. OP
    OP
    AussiePhil

    AussiePhil Dedicated Elf Administrator

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    Ok

    First video of the RGB Strings running from the TigerDMX48.

    The supply voltage is 5.5v at the SMPS output (as far as i could adjust it up). As shown in the video the cable from the SMPS to the controller is about 3 feet.

    The 100 modules draw around 6A when all on and this WILL cause enough voltage drop from the SMPS to the controller to cause the LED drivers to lock up IF the cable is too long.

    Other than that these work quite well with quite good colour mixing.

    Over the next couple of weeks i'll look at putting these outside for a full on test, need to write a self running firmware for the controller.

    Untitled

    What would be good to do from a controller viewpoint is to use the split power capability and use the first half at 12/24/36/48v and use the second half at 5.5v to drive the RGB Strings. You would still need to mount the power supply close by.

    I will look at the possibility of a 16/24ch board just for 5v use.

    Cheers
    Phil
     
  6. dmoore

    dmoore Senior Elf

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    These do look good - they look just like the 6803 chip'ed versions with the little gap between the wires on the bottom. Thanks for "reviewing" them.

    David
     
  7. Nixay

    Nixay New Elf

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    Is this 4A current draw for 200 lights only with 1 colour on? From your post that suggests 20mA per LED per colour I would expect to see 12A current draw with 200 lights emitting white?

    These look very interesting to me, although I would have preferred a 12V working voltage.

    Nixay.
     
  8. OP
    OP
    AussiePhil

    AussiePhil Dedicated Elf Administrator

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    Nixay

    Sorry i have fixed that error...

    Each RGB light will draw 60mA when showing white. 100 of them will draw 6A.

    Very bad of me to make that mistake.

    Cheers
    Phil
     
  9. fasteddy

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

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    IM SHOCKED, YOUR HUMAN
     
  10. fasteddy

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

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    Or was it a faulty CPU module :D
     
  11. Nixay

    Nixay New Elf

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    Well, I've been running these light strings on my display for 5 nights now, and unfortunately they are not living up to their "water-proof" description. We've had some rain but had our first real downpour last night and now I have a dead short between green and common on one of my strings (2x 50pcs joined end to end) and another one which has green doing a slight flicker across the whole string. Also a number of reds have either stopped working or are flickering on individual LEDs. Rather disappointed that I haven't made it past December 1st with these.

    - Nixay
     
  12. Tabor

    Tabor Full Time Elf

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    There has been lots of discussion on performing some extra water proofing to these strings.

    Did you take any steps to make them more water proof?
    May help someone else to save theirs.
     
  13. Nixay

    Nixay New Elf

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    No, I didn't do anything to otherwise water proof these lights. They were advertised as being water proof and they looked pretty water tight when I got them so I didn't think much of it. Now that I look at them and the way they actually hang in our bushes (in a downwards direction, because they're quite bulky) I can see that water can get into them from between the lead-in and lead-out wires. They appear to be water tight on the outside of the wires but not the inside.

    I had actually thought it looked like the modules had silicon sealing over the internal connections beneath the module housing but that is obviously not the case.

    - Nixay.
     
  14. mrpackethead

    mrpackethead Full Time Elf

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    Sigh... perhaps the first of many people who are going to learn this lesson the hard way... its possible, but quite difficult to seal them up.. However once they have been wet, you're really in trouble, because the moisture will start to corrode the pcb and then bad stuff happens.. The construction technique that 90% of the manufacturers use is using injection molding to over mold the wires.. Unforuantly this simply does'nt work...

    You might be able to rescue them somewhat by drowing them in methelated spirts, which will displace the water, then drying them out for 2-3 days in a warmish spot..
     
  15. fasteddy

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

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    What strings are these, are they the 6803 or the 2801 or the 2801 UV cable type, there are some differences

    Another thing, how did you have the string mounted, where they hanging with the leds pointing down so the water could collect in between the cables and then seep in. A bit more info on the issue may help us all understand a bit more.

    Thanks
     

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