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Lighting bridgelux full-spectrum leds (400nm-840nm)

Discussion in 'General Aquarium Discussion' started by Tim, Nov 24, 2015.

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  1. Tim

    Tim Member Trusted Member

    Dear readers,

    I recently ordered some chinese bridgelux led spots for my upflow scrubber. I have 2 holders for e27 spots and decided to go with 2x15w (5x3w) grow lights. I got in touch with the seller and explained that I really wanted the 3w version and not the 1w version.. however the seller told me that a 5-7w diver is used to extend the lifetime of the leds.. if this is true or not.. I don't know. Anyway the actual wattage will be around 5 watt, I have been told. I wonder what you think about this led spot.. it peaks at 450 in the blue spectrum and 650 in the red.
  2. Tim

    Tim Member Trusted Member

    [​IMG] Here are some pictures:
  3. Tim

    Tim Member Trusted Member

    What I noticed is that the graphs do not exactly match:
  4. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    Yes, this is typical for LED manufacturers and that is why I wrote up that as a heads-up in the resource for the stock LED fixtures. What they will do is under-drive the chips so that the odds of a chip burning out are almost nothing. Driving a 3W chip rated for 700mA at 300mA reduces the heat stress (and the requirement for eat sinking) way down, and this increases the life dramatically. But it also decreases the output and makes for a fake marketing power rating.

    So to start, a 3W 660nm chip does not really consume 3W. If you look at Philips 660s they drop about 2.2-2.4V across the chip at 700mA. Power = volts * amps so P=(2.4)(0.7) = 1.68W. Now decrease the current to 300mA and your voltage drop will actually be less, so 2.2 * 0.3 = 0.66W, that's you actual wattage draw per LED at that current.

    So using their math, they are likely driving the chips at close to 700mA, maybe 650mA, and then 3 chips * 2.4V * .65A = 4.68W driver, add a little loss factor for the driver and you are closer to 5W. So that's how, magically, a "15W" fixture is really a 5W fixture.

    In contrast, my LED boards drive 6 660nm chips at 700mA, so 6 x 2.4 x .7 = 10W per board of actual wattage draw, not including the violets and not including the power loss of the driver. So there's a reason that I don't advertise that as a "18W" board, or any wattage really, because LED wattage is a lot of false advertising. The reason is marketing, if they started calling an LED what it is based on actual wattage draw at rated max, people would get all confused when you offered a 1.7W chip even though that's what it really is - because it used to be a 3W chip, but tech has gotten better and what used to draw 3W of power years ago now draws 1.7, with the same flux output as the original 3W chip.
  5. Tim

    Tim Member Trusted Member

    Wow, thank you for elaborating on the subject. I never new this.. good to know, I asked many chinese led manufacturer about this and a few of them admitted that the actual usage is much lower.. too bad their are not many genuine and reliable companies out there..

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