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Where's The LED's?

Discussion in 'Home Power and Microgeneration' started by Bob Adkins, Oct 22, 2003.

  1. Bob Adkins

    Bob Adkins Guest

    White LED's are cool (and kewel too!) and extremely cheap lighting. The
    prices have dropped precipitously, and should pay back very quickly.

    Why are they seldom mentioned as a means to save energy?

    Will they become mainstream before the energy saving specialists (that would
    be us) embrace them?

    I know their light takes some getting used to, but the up side is
    tremendous. For 1 thing, they save nearly double in cooling season. That's
    important in the Southern US where cooling is used 8-9 months out of the

    I suppose LED's are best for point lighting rather than general area
    lighting in home settings at this stage in their development. However, they
    should be fine for shop, cabin, and security lighting.


  2. Save energy compared with what? Last time I checked, white LEDs were
    about as efficient as incandescents, much less than fluorescents. Has
    their efficiency improved recently?

    Tom Q.
  3. Bob Adkins

    Bob Adkins Guest

    I dunno. Hey, waitaminute...who's asking the questions here? :)

    Here's what I know, which isn't much. That's why I asked.

    My LED flashlight with 3 AAAA cells will last about 2 weeks continuous. My
    fluorescent flashlight with 4 AAA cells will last about 2 hours. <shrug>

    Fluorescent tubes last 6-12 months. LED's last 11 years. <shrug, shrug>

  4. mark Ransley

    mark Ransley Guest

    and the lumen comparison of the 2, the flourescent is the winner
  5. LED's are great, don't get me wrong. I just didn't think that they
    were all that efficient at producing white light (but they may have
    improved since I last checked - a year or two ago). I'm assuming that
    your fluorescent light puts out a lot more light than your LED
    flashlight. If you don't need much light, LEDs might be the right

    Also, cheap is relative. I'd hate to have to pay for enough LEDs to
    replace a couple of 4 ft T8 fluorescent fixtures.

    Tom Q.
  6. Bob Adkins

    Bob Adkins Guest

    We're obviously not talking about the same LED's. My tiny little flashlight
    will knock your eyeballs out. White LED's have dropped to around $1 apiece
    in bulk.

    I heard a 80W equivalent LED bulb uses 180ma @120v. But that's only a rumor.
    If only half true, imagine the possibilities.

    While most multi-LED bulbs are still very expensive, the price is dropping

    I thought perhaps this group would be intrigued by them before the general
    public. Guess not.

  7. Steve Spence

    Steve Spence Guest

    LED's are no more efficient than incandescents. However, their tiny
    consumption (and corresponding tiny lumen output) make them ideal for task
    lighting and instrumentation where incandescents are overkill. It's a matter
    of scale and appropriateness. CF's are the most efficient, and the most
    appropriate, for area lighting.
  8. Steve Spence

    Steve Spence Guest

    The replacement cost for an LED is much higher, but life is much longer,
    meaning fewer or no replacements needed.
  9. Steve Spence

    Steve Spence Guest

    Check the lumen output on your LED's compared to your fluorescent. That
    explains the usage differences. per lumen, cf's are more efficient than
    Very true. Nothing to do with power consumption however.
  10. OK, I picked a couple of examples at random (not really random, the
    Luxeon name I remembered from when it was announced as the brightest
    white LED a little while back, the Phillips fluorescent was the first
    hit in a Google search).

    Luxeon 5W LED - 120 lumens
    Phillips 30w T8 fluorescent - 2750 lumens

    So it would take 23 LEDs and 115 watts to generate the same lumens as
    the T8 lamp generates with 30 watts. Maybe you can find some more
    efficient LEDs, but now you have something to compare them to.
    Aw, c'mon Bob, don't be that way. <g> Hey, if I could snap my
    fingers and make the LEDs more efficient, I would.

    Tom Q.
  11. Steve Spence

    Steve Spence Guest

    analogZONE Says . . .

    LED-based lighting is gaining popularity because of its long life, power
    efficiency, and highly flexible form factor. Where it's practical, compact
    fluorescent lights are still the most energy-efficient at 50-75 lumens/Watt,
    but at 24 lumens/W, the Luxeon devices are much better than the 12-15
    lumens/W offered by standard incandescent bulbs.

    Cost? $50 or $.41 / lumen

    CF cost? $6 or $.008 / lumen
  12. Bob Adkins

    Bob Adkins Guest

    Look Tom, we know you're holding out. Snap those fingers!

    LED light is different. I don't know if you can really compare lumens. ( I
    know how sacrilegious that sounds)

    It's a high color temperature light. I bet it's near or over 9300K. I don't
    think fluorescents are nearly that hot. Let's look at a little 300 lumen
    incandescent, fluorescent, and LED. Colors with the incandescent would
    probably look dull. Better with the fluorescent. Very rich and vibrant with
    the LED.

    My guess is based on using all 3 types of light, not from lab data. (That's
    not my job)

  13. mark Ransley

    mark Ransley Guest

    9300 k I thought the sun was 5500 k
  14. mark Ransley

    mark Ransley Guest

    All light can be and is rated in lumens, I checked out a few sites but
    cant find lumen ratings. Ledtronics has a good selection. But the
    cost !! Everyone will buy them when the price is worthwhile. Your
    led flashlight is focused your flourescent tube 360` full lighting.
    Unscrew a mag lite or regular flashlight lens to expose the bulb and
  15. Vaughn

    Vaughn Guest

    True, but you were responding to a post about white LEDs. Unless
    something has changed recently, red and yellow LEDs are far cheaper and more
    efficient than white LEDs which makes them increasingly practical for things
    like tail lights. If you look closely, you will see that many traffic
    signals now use LEDs.

  16. Guest

    Actually, my LED headlamp is a little much for reading; I like a PALight on
    low beam for that.

    Now if the PALight guys would just make a headband to fit the damn thing...
  17. david

    david Guest

    whay not use the same technology that those lazer pointers us for light only
    use white insted of red to me it seems like that would me a very powerful
    flashlight or light bulb with very little energy use
  18. Well, to start with, lasers are monochromatic, and white isn't, and
    laserpointers have nothing to do with efficiency...
  19. My info (recalled rather poorly, but I will input it anyway) shows that the
    LEDs range from about as efficient as very efficient incandescent bulbs, to
    about half as efficient as typical fluorescent bulbs. They are mechanically
    very rugged, and can have several thousand hours of operational life. For
    things like night lights, the incandescent bulb is much lower in efficiency.
    I think this was dealt with in an article in Electronic Design magazine,
    perhaps about a year ago.
  20. Tony

    Tony Guest

    Daylight tubes run around 6500K (from memory).
    We were using them for starting seedlings in the spring.
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