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Thread: red/blue led grow bulb

  1. #21
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    That is really odd. So none of the LEDs worked after taking the optics off?

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    Quote Originally Posted by Floyd R Turbo View Post
    That is really odd. So none of the LEDs worked after taking the optics off?
    No, none of them work .It seems like the optics and the upper plate push the plate with LED down to have some kind of contact and them the bulbs lites up.

  3. #23
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    Sounds like that particular one has some kind of contact like you mentioned. That's pretty strange though. Have you tried a process of elimination? Remove just one optic and see what happens. See if there is one particular chip that is "breaking the chain". You might have a bad connection on one chip that is being held in contact with the lens. If one contact is lost, then the whole array will not work.

    I would not think that they would have designed it such that it would not work without all the lenses in place. I would think what you are experiencing is a defective product. Try the elimination process first though.

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  5. #25

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    Quote Originally Posted by SantaMonica View Post
    a lot of reviewers have problems with those like wrong led's, burnouts.The Philips 14.5 watt led 2700k flood would work really well. saw them for about $20 at homedepot

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    LED 2700K is not the same as CFL 2700K. CFLs use phosphors to shift base UV light to visible, so there is a large spectral mixture. LEDs are element based and give out a completely different signature. That is why all LED grow lamps you see are 660nm red and not 2700K WW - because LED 2700K doesn't work for growing plants, at least not growing them at the optimal pace.

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    Quote Originally Posted by Floyd R Turbo View Post
    LED 2700K is not the same as CFL 2700K. CFLs use phosphors to shift base UV light to visible, so there is a large spectral mixture. LEDs are element based and give out a completely different signature. That is why all LED grow lamps you see are 660nm red and not 2700K WW - because LED 2700K doesn't work for growing plants, at least not growing them at the optimal pace.
    they use phosphors for leds aswell (its cheaper) then elemental based ones.

    CFL's with no phosphors emit mostly harmful UV light

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    I didn't say that we use CFLs without phosphors. All fluorescent tube lighting is UV on the interior. The phosphors shift that light into visible light. This is why a UV fluorescent tube is totally clear. That's what all fluorescent tubes are like if you take away the phosphors.

    I am aware that there are phosphors applied to LEDs as well. But it is still a totally different form/source of light.

    Many have tried WW LEDs and they don't work as well. I have been meaning to do some sorts of testing but have never gotten around to it. One thing that could be the issue is that 660s output a much lower intensity that other LEDs. Similarly, deep violet. But when you throw on CWs, RBs, etc, these tend to overpower a screen. This might be the reason why WWs haven't really worked as well. But regardless, there is still 'wasted bandwidth' in any other LEDs inside the deep red through royal blue spectrum.

  9. #29

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    Quote Originally Posted by Floyd R Turbo View Post
    I didn't say that we use CFLs without phosphors. All fluorescent tube lighting is UV on the interior. The phosphors shift that light into visible light. This is why a UV fluorescent tube is totally clear. That's what all fluorescent tubes are like if you take away the phosphors.

    I am aware that there are phosphors applied to LEDs as well. But it is still a totally different form/source of light.

    Many have tried WW LEDs and they don't work as well. I have been meaning to do some sorts of testing but have never gotten around to it. One thing that could be the issue is that 660s output a much lower intensity that other LEDs. Similarly, deep violet. But when you throw on CWs, RBs, etc, these tend to overpower a screen. This might be the reason why WWs haven't really worked as well. But regardless, there is still 'wasted bandwidth' in any other LEDs inside the deep red through royal blue spectrum.
    Phosphor led's are not the perfect bulb, elemental based are a little more efficient but here is a lot of wasted bandwith in CFL's as well and we know they work.philips rebel Click image for larger version

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ID:	4940 CFL 2700kClick image for larger version

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    Both are using material to slow light down

    also consider other problems with cfls

    -Light is scattered everywhere even backwards towards a reflector
    -Wrong temperature ruins intensity
    -500 hours of operation gives a 10% perminent drop in intensity

  10. #30

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    this vid made me feel most photosynthesis response charts are exagerrated.

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