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Meteor lights with cheap, non isolating, potential death trap transformers

Discussion in 'Power Supplies' started by videoman3857, Feb 11, 2018.

  1. videoman3857

    videoman3857 Full Time Elf

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    Last Christmas display we had a handful of snow fall /meteor shower lights that were the talk of the display in the seated refreshment area.
    On Friday, to my pleasure, saw the delivery of 30 more of aforementioned lights that I ordered off E-bay for a quarter of the price I paid for the ones on display.
    These units were supplied with a "USA" plug in transformer and despite me telling the supplier that I did not want the "USA / Australia power adapter" they sent them anyway. My intention is to use a 5V psu to supply power to this number of lights. - so much easier than power boards and leads all over the place.
    I also had in my mind the need to "Extend" the leads so I can distribute the power from a central point.
    The lights themselves seem to be well constructed. The light lead connects to the transformer via a 2 prong screw together pigtail type connector. The distance between the first tube of leds to the transformer is a mere 30cm.
    How the manufacturer expects one to display the lights and keep the transformer out of the weather i will never know.
    That being said, I have no real issue with the length of the cable as I was going to extend the cable length anyway.
    Remembering that I read somewhere else that some of these cheap Chinese manufactured transformers are dangerous as the do not isolate the 240 ac power from the 5 volt dc side, I decided to pull one apart. Low and behold.
    The transformer is just that - a cheap, no isolating, sub standard potential death trap.
    Visiting David_AVD new store, I stumbled accros the same thing - though Davids post was about coloured meteor tubes.
    I "liberated" a copy of his photo of the said type transformer to show / remind you of these poorly designed transformers. transformer.jpg dodgy_led_psu-240x300.jpg
     
  2. David_AVD

    David_AVD Bite my shiny metal ass! Community Project Designer Generous Elf

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    I was thinking those photos looked familiar !
     
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  3. diyer

    diyer Full Time Elf Generous Elf

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    Over the last couple of years I have bought a number of sets of these from different eBay sellers, all of the 5v variety although I have seen some mains voltage powered and some solar. The power supplies I have received have all been US flat pin or Euro round pin types, some with SMPS and some capacitive dropper, doesn’t matter, they all went in the garbage bin.
    I joined a heap of sets together and power injected along the string and used a buck converter to power. The main issue I have is water ingress from the top caps, I noticed that some were going rusty so I ended up taking the bottom caps off the ones that leaked. The moisture didn’t seem to affect them overly.
     
  4. David_AVD

    David_AVD Bite my shiny metal ass! Community Project Designer Generous Elf

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    Yeah, I put heatshrink around the top of the tube, filled with silicone and shrunk them to force some of the silicone out. That seemed to seal them well enough.
     
  5. OP
    OP
    videoman3857

    videoman3857 Full Time Elf

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    I had moisture inside the ones I used at Christmas.
    I could't make up my mind if it was water ingress from the rain or condensation forming from the heat/direct sun on them.
    Either way, I ended up drilling a hole in the bottom of the tube to let the water out.
    I think I might try David's idea of the heatshrink and silicone on this new lot. :thumbsup:
     
  6. David_AVD

    David_AVD Bite my shiny metal ass! Community Project Designer Generous Elf

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    Even with the tops sealed they do get condensation, so best to leave a hole in the bottom of the tube.
     

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