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OT: LED based bulbs. What's your experience?

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  • OT: LED based bulbs. What's your experience?

    I've decided to try those bulbs consisting of multiple LEDs and designed to be used in a regular light bulb socket. Bought a couple of different ones on eBay. Both from the more powerful variety, but with different spectrums. So far I received one with, presumably, 6500-7000K color temperature.

    Gosh, what a horrible device this is! Although it's supposed to be a 1050 lumen bulb, it looks as dim as a night light. And the color is so ugly (blueish-grey) that I can hardly stand it at all (let them tell somebody else how 6500K spectrum looks: I deal with those bulbs on everyday basis). The only possible use for this garbage would be in Hollywood to light night scenes in morgue.

    Is this because it's a cheap chinese crap or all of them are that bad?

    Here is the one I tried: http://www.ebay.com/itm/E27-13W-110V...item415fc261e6

    Still waiting for a "warm light" one to arrive. It's supposed to be a bit more powerful, and I hope the spectrum will be, at least, tolerable.

    P.S. Yes, I'm well aware of different eye sensitivity to different parts of spectrum (perception of brightness) and other related issues. I also took into consideration the difference in design (direction of light) between those corn cobs and regular luminiscent lights. And I knew it will be on a bluish side. Still I didn't expect them to produce such a totally unacceptable result.

    What's your experience with those bulbs? Do you know how they connect LEDs there: in series or in parallel (which will make a night and day difference (pan intended) if one of the LEDs fail)?
    Last edited by MichaelP; 12-23-2011, 04:11 AM.

  • #2
    I've been a bit leery of those 'corn cob' type light emitting units. I've bought a couple of more normal looking ones (can't recall the manufacturer, possibly Lights of America). They use the more normal looking leds, and there are more than 60 of them standing up on a circuit board. One was warm white, the other I bought was 'bright white'. I like the warm white, and the bright is, well, brighter and less warm. Even the bright white is less blue than the white leds of the past, but the warm white was actually fairly pleasant.

    I say was because I actually bought them for the leds. I've used several of them so far in some tiny keychain flashlights I was making. Needless to say, I destroyed them to remove the individual leds.

    Taking a guess here- I'd say that about ten of the individual leds fired up would produce about as much light as a nightlight using a 7 watt bulb. It almost sounds like there's something really corny about your bulb-
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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    • #3
      You got crap Chinese LED's.

      Buy the real stuff. Buy CREE

      Disclaimer: CREE shareholder.

      Comment


      • #4
        My LED experience, so far:

        I tried the one on the right first. It's a Sylvania, but I don't remember the model name or the color temperature. I bought this to use in some lamps that had unvented shades that were getting too hot with an incandescent bulb. A major problem is that all of the light goes out the top, and none flows down to the bottom of the shade and to the tabletop. This seems to be the common design with these LED units. I don't know the color temperature on this one, but it is much too blue and harsh.

        The one on the left is a GE. It does a somewhat better job of distributing the light, and is listed as 3000K color temperature...closer to an incandescent. It also cost a good bit more than the Sylvania...about $34.00 instead of $28.00



        I think the manufacturers are on the right track with these, but there is still a long ways to go. The bluish light is harsh, hard, and annoying. Hopefully as time goes by we will be able to get LEDs that more closely replicate the output of incandescent lamps.

        On the other hand, they do operate at a MUCH cooler temperature, and can save a lot of money in the long run if you keep a lot of lights on all the time.

        (Another problem with the Sylvania units is the the packaging was poorly done; the bulb is in a plastic clamshell within a cardboard outer wrap. The clamshell is not held together in any way, and as soon as I removed the first one from the outer pack the clamshell popped open and the bulb fell out and shattered.)

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        • #5
          Originally posted by beanbag
          You got crap Chinese LED's.

          Buy the real stuff. Buy CREE

          Disclaimer: CREE shareholder.
          I just looked at the CREE website. I don't see anything that can directly replace a traditional incandescent bulb and provide a nearly spherical light output.

          Comment


          • #6
            I have not tried any, in fact, I recently went out and bought a bunch of 120 W interior floodlights for my living room. I should have enough to last another 10 years or so.

            That said, I was discussing this recently with a friend that had converted his living room lighting to LED and he was very pleased with it. Don't know what brand, I'll try to find out.

            I have another friend that tried LED floods for outdoor use. Half the lamps that were supposed to last 7 years or more failed in less than 7 months. He had to send the failed lamps back to the manufacturer for replacement, and the color of the new ones didn't match the color of the remaining ones. He was less than pleased...

            I guess this is to be expected with a government mandate.

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            • #7
              There are many problems with using "led light" as a generic term. The differences between them can be as great as the difference between a HF mini-lathe and a full blown Pacemaker. The design, the materials and engineering all make a difference.

              An LED is a solid state semiconductor and as such it has the same vulnerabilities to power spikes and over heating as any other device. A typical cheap 'corncob lightbulb' simply puts enough LEDs in series that each one uses ~ 1/35 of the line voltage. If any one bulb fails open, they are all gone. If any one fails shorted, the voltage in the rest goes up and they fail quicker.

              A well designed one has a usable heatsink and fins to dissipate the heat that is generated by the LED and it's power supply. The power supply is there to ensure the LED gets the proper voltage/current and to filter out spikes.

              An LED that is properly cooled and run at the current that it is designed to use will last quite a while, often 11 to 15 years of constant use. But... if they are run at maximum current (often twice as bright) the life falls to months or years.

              The reason that steve45's friend was not able to get lights that matched his first set's hue is that the lower cost LEDs have a lot of variation. The manufacturers save money by simply gathering all the leds from each batch that are close to the same and sell them by 'bin'. A light made from all LEDs from the same bin will be close in color. A light made from LEDs from random bins will have a lot of different shades of white, usually ranging from snowy white to blue to yellow to 'cat piss green'. Red is noticeably absent from most white LED lights.

              In general, if you see 40 or more LEDs then the bulb will have unpredictable quality, color and unknown lifespan.

              I only have one LED "40 watt equivalent" bulb, and I bought it as an experiment. My wife did not like that it was brighter and whiter than the one it replaced, so it has been relegated to an area that only I use.

              Dan
              Last edited by danlb; 12-24-2011, 05:40 AM.
              At the end of the project, there is a profound difference between spare parts and extra parts.

              Comment


              • #8
                Originally posted by john hobdeclipe
                I just looked at the CREE website. I don't see anything that can directly replace a traditional incandescent bulb and provide a nearly spherical light output.

                The nearly spherical output can be accomplished by the use of frosted bulbs and clever reflectors. An easy way to bypass the clever reflectors is to use frosted bulbs with 3 LEDS (each has a 125 degree 'beam') pointing outward from a central post. Three Cree XM-L LEDs running at only 700 ma each ( at 3.2 volts) will consume only 7 watts and output about the same light as a good 75 watt bulb (780 lumens). 700ma is the "long life" setting for that LED. If needed it can run as high as 3000ma per LED and put out 3 times the light.

                Yeah, I've been into LED lighting for a decade or so.

                Dan
                At the end of the project, there is a profound difference between spare parts and extra parts.

                Comment


                • #9
                  Originally posted by danlb
                  I only have one LED "75 watt equivalent" bulb, and I bought it as an experiment.
                  What exactly bulb was it, Dan?

                  Comment


                  • #10
                    Originally posted by MichaelP
                    What exactly bulb was it, Dan?
                    Darn. I mis-remembered. It was a '40 watt' equivalent by Utilitech.. (post corrected) I bought it at Lowes.

                    http://www.lowes.com/pd_223319-28839...Info=4%20-%205

                    I tried to replace the 40 watt "reveal' bulb that was in the lamp in the living room since it is on 8 to 12 hours a day. It made the room too bright for her.

                    Dan
                    At the end of the project, there is a profound difference between spare parts and extra parts.

                    Comment


                    • #11
                      light output

                      I have been looking at the Philips brand of GU10 led replacement light bulbs but -so far - have called it off when [email protected]! qqqqqqqqqqsaw the price (~$30 Cdn each).

                      While heavily promoted for their plus attributes - low power consumption & long life - I am interested in the light output. Specifically, is a GU10 LED's visible light output (lumens or candlepower, or whatever) anywhere near that of the 'good-old-standby' halogen?

                      Comment


                      • #12
                        Thanks, Dan. I was trying to find something with the "regular" E27 socket and much more bright than a 40W equivalent. Looks like they don't have any of the same brand/construction. And it sounds like it'll cost a fortune that will totally negate its purpose (unless one is a Green Peace activist).

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                        • #13
                          I'd sure like longer life for the living room 3-way bulbs. This time of year they are on 12-15 hours a day.

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                          • #14
                            The economics of low wattage lights are directly tied to the price your local power company charges.

                            My power is more expensive if I use more than a certain amount. It's a tiered system, like our taxes. I end up paying 1/3 of a dollar (36 cents) for every 10 hours that a 100 watt bulb runs.

                            The kitchen/dinning room light is on most of the day, so that bulb costs about $10 a month to run. Change to an 12 watt LED and I pay around a dollar a month for the same light. The payback for a $30 bulb is 3 months for me.

                            If I were to cut my electricity use to about 1/4 of my current use, the rate would be only 12 cents per KWH, so the payback gets closer to a year. If it lasts longer than an year then I'm ahead of the game.

                            The cost to build an LED light bulb is directly related the choice of led type and the premium involved in buying color matched LEDs. 80 low powered commercial grade LEDs are less than 10 cents each. A design using 3 high power, high output, high CRI LEDs will pay 5 to 15 dollars per LED.

                            I don't seem to get a long life from the compact fluorescents, and I dislike the idea that I'm throwing away an energy intensive, mercury filled light bulb instead of a nice, inert tungsten filament bulb. There was a development a few years back that created a incandescent bulb with a filament that had a tungsten lattice. It was 10 times more efficient than a standard incandescent.
                            http://www2.electronicproducts.com/T...2002-html.aspx
                            At the end of the project, there is a profound difference between spare parts and extra parts.

                            Comment


                            • #15
                              Originally posted by Dunc
                              I have been looking at the Philips brand of GU10 led replacement light bulbs but -so far - have called it off when [email protected]! qqqqqqqqqqsaw the price (~$30 Cdn each).

                              While heavily promoted for their plus attributes - low power consumption & long life - I am interested in the light output. Specifically, is a GU10 LED's visible light output (lumens or candlepower, or whatever) anywhere near that of the 'good-old-standby' halogen?
                              --- slightly simplified ---
                              The light power rating can be can be given in lumens (total light output in all directions at once) or in candlepower (how bright it is at the brightest spot at a standard distance). The candlepower can be impacted greatly by the presence and shape of reflectors or lenses.

                              If you look at the LUMENS rating of the good old standby halogen you will see a bit of variation, since different filament designs heat up and radiate light differently.

                              I found a chart at http://www.lighting.philips.com/us_e...oad/p-8632.pdf that lists the lumens of average incandescent lights ( page 6 )
                              Given that 35 watt halogen, MR16 bulb with a GU10 base creates 480 lumens concentrated in a 25 degree beam, you simply need to find another bulb that makes similar light. Phillips lists a 4 watt LED in the MR16 form factor that is 10 lumens higher output than the 35 watt halogen mode.

                              One interesting point that some people have discovered is that they are over lighting their homes. Your eyes limit the amount of light you see. A common saying among flashlight collector's is that most people can not perceive the difference in light output until the lumens are 50% greater IF there is no direct comparison. If the brightest light in the house is 75 watt, ( 1000 lumens) then your irises open up and the room appears just as bright as if you have a 100 watt (1500 lumen ) light. The trick is to use even lighting levels.

                              The flip side to that last paragraph is that many older people can focus better when their iris is shut down. The depth of focus is much greater under bright lights. Oh well.

                              Dan
                              At the end of the project, there is a profound difference between spare parts and extra parts.

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