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    AA flashlight for friend headed to Afghanistan

    I have been eyeing this Energizer 2XAA LED: It is expensive but very bright, 110 lumen, if you believe the spec sheet. Simple to operate tail switch; push to turn on at...
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    Thanks, the ELMCL21L that is rated at 110 Lumens looks interesting. Anyone tried one, are you impressed with the brightness?
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    So is this model from BrightGuy that the package rates at 110 lumens; is it a diffeent version?
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    LED Genius aims for 100% efficiency

    Given that the LED converts 100% of electrical input into (monochromatic) light the lumen output is going to depend on the efficiency of the phosphors.
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    LED Genius aims for 100% efficiency

    So, the best I can tell from the magazine is that by 100% efficiency he means all of the power delivered into the LED produces light, none of the power is wasted as heat. So a blue emitting LED driven by 5 watts electrical input would output 5 watts of blue light.
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    L2D runtime on primary lithiums

    There are many types of "lithium" cells with widely different voltages.
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    L2D runtime on primary lithiums

    The two types of cells have about the same energy content - 123 cells delivery about half as many ampere-hours but at about twice the voltage. I believe that they are entirely separate and unrelated companies.
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    L2D runtime on primary lithiums

    Lithium AA cells are a different chemistry from 123 cells and I have not seen any reports of Lithium AA cells "venting with flame".
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    How many prefer AA battery powered flashlights?

    I only buy AA cell lights. All my other devices use AA cells - camera, GPS and 2-way radio. If I had a light that used 123 cells I would have to carry spares just for it. Lithium AA cells perform just as well as 123 cells.
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    Lithium primaries in AAA light?

    Not really, 2 lights I know of from experience that do not tolerate Lithium AA cells are the PrincetonTec Surge and the Minimag AA Incandescent. In the Surge the bulb will fail almost instantly. In the Minimag with a fresh set of Lithium AAs the bulb will likely fail if given a little mechanical...
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    Neodymium magnets kill flashlights?

    If one Googles "magnetic braking" or "magnetic braking copper tube" he will find lots of people who believe that the slowed fall of a magnet in a copper tube is due to eddy currents. here are links from the University of Illinois...
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    Neodymium magnets kill flashlights?

    Unrelated to the magnetic in a copper tube discussion but here is a link that has video of a frog and other objects being magnetically levitated: The strawberry is the most stable when being levitated.
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    Neodymium magnets kill flashlights?

    It is a fact that a strong magnet dropped through a copper tube has its fall significantly retarded and this effect is produced by the magnetic field. You should try it. Since you say that it is not due to induced currents in the copper tube creating an opposing magnetic field then perhaps you...
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    Neodymium magnets kill flashlights?

    Someone had shown me this many years ago, a strong magnet is very noticeably slowed during its fall. I had never seen an explanation but had always assumed that it must be due to currents induced in the copper pipe creating a magnetic field to oppose that of the permanent magnet.
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    Mag Led 2AA lithiums ok to use ?
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    Streamlight LED Survivor

    If this light is regulated then I wonder why the packaging says that using Lithium AAs will cause damage?
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    UK 4AA eled (standard): availabilty update

    Thanks, I ordered a couple of those. It is too bad that these older 4AA LEDs are being discontinued. On a related note: I was going to order a couple of UK4AA 4-watt Xenon lamp modules along with the LEDs. I was shocked to discover that BrightGuy now lists the retail price for these UK4AA...
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    CMG Infinity Ultra? Did I get screwed?

    The brightness _is_ different. The Ultra is significantly brighter. Don't know anything about the hard anodizing, that is not something I care about. Obsoleted how? I use them as backup lights on my helmet. What is better?
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    LED lanterns - looking for the good the bad and the ugly (best/worst)

    Why do you want LED instead of fluorescent?
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    Color bins - what is the cause?

    Thanks for this link. It is a good resource. Here is one article that is relevant to my question though it is several years old: