Full description not available
R**.
You'll Put Your Eye Out With This Light!
This thing is awesome and SUPER BRIGHT! The only issue is that there are no markings whatsoever to indicate the direction to insert the battery. In fact I thought I had them in correctly and even requested a return authorization because it would not come on, then I decided to reverse the battery figuring that since the light did not work doing so could not harm it anyway. KAPOW it worked when I reversed the battery. Sooooooooo by trial and error I learned that if you put the battery in and it does not work, then just turn the battery the other direction and try that. Putting the battery in the wrong direction did not harm the light, it just would not come on.One other consideration is that the same model# batteries from different manufacturers ARE DIFFERENT LENGTHS so do not tighten the light end cap on this light all the way down without paying very close attention to how tight the last few turns feel or you could damage the light if you happen to be inserting longer batteries. On longer batteries you may not be able to tighten the cap all the way down. In that case, just get different batteries that are shorter and all is well. However, I had some that were so short they shook inside the light and others that were so long the cap could not be tightened all the way. Not a problem with the light, rather sizing inconsistencies among battery mfgs.
M**R
BRIGHTER THAN THE SUN...(but plese read more...)
This a truly astonishing hand-held flashlight design (the 15 LED version)..But after reading some of the other reviews that report a variety of problems with this flashlight, I am very surprised. I purchased 2 of these (at the same time), along with 4 (8, actually) Tangsfire 26650, 6800 mAh, Li-Ion batteries, and a pair of NiteCore i4 charger units.After coating the threads of the body tubes with high drip-temp lithium grease (DO NOT USE VASELINE--IT WILL LIQUIFY AND POSSIBLY CONTAMINATE THE INSIDE OF YOUR FLASHLIGHT), I inserted the batteries and attached the end caps. NO battery compression problems, no denting of the bottoms of the lowermost battery, no funky behavior of the tail-cap switch, and DEFINITELY no problem with these Tangsfire batteries, which apparently are equipped with protection circuitry.Both lights assembled easily, worked perfectly from the very first power-on, and cycled reliably through all five power modes flawlessly many, many times. Frankly, my biggest frustration was with the NiteCore chargers, which won't hold (4) 26650 batteries at the same time (their diameter is too large for the individual charging "bays"), and how long it took to charge the batteries, especially since they were still partially charged when they arrived. But that's a different product complaint.This flashlight is basically a "PHOTON CANNON". The Cree U2 T6 LEDs emit most of their light in what is generally considered the "cool white" portion of the spectrum (the specific color temperature is stated in the Cree product literature). But this flashlight puts out so much optical energy that if you shine it on your cheek at a distance of 12-18 inches you can actually feel heat. DO NOT shine it into your eyes with your eyelids closed. The eyelids are NOT opaque enough to stop a potentially damaging amount of light energy from still making it into your eye.The beam pattern of this flashlight is unlike almost any other fixed-focus, hand-held flashlight on the market. The central cluster of LEDs are concentrated into a central, unified beam of exceptional brightness, while the LEDs in the central and outer rings of the head create a broad outer portion to the composite beam, This gives an overall illumination pattern that lights up EVERYTHING in a very wide field in front of you. Something like this could never be done without the number and sheer combined intensity of all the LEDs used in its design.For those who are under the impression that their 1,000 to 2,000 lumen lights are just as bright, this just isn't so. I've been testing these two units against a number of other 1,000+ lumen lights, both fixed and variable focus. Some variable focus lights might be able to produce a spot beam that appears to compare with the most central portion of this unit's composite beam, but that's the extent of it. When you need lots of light (search and rescue, night spotting of flying animals and insects, etc), where sustained wide-field illumination is paramount, you can't just keep sweeping a spot beam around and expect that to work. You need something like this.As impressed as I am with this unit (and I will be putting as many of these in the hands of as many people as I can, while they are still available), I still look forward to future generations of of lights that are capable of concentrating many thousands, or tens of thousands, of lumens into a focusable, concentrated beam (but still affordable). For that we will have to wait for new generations of higher luminosity LEDs, higher efficiency LEDs, or some really creative optical designs.GET ONE WHILE YOU STILL CAN!Mindflyer-P.S..=I will be doing heat testing, battery life testing, and if I can get hold of a laboratory-grade photometer, I will do a true luminance profile. More to follow.
M**N
Awesome brightness in a convenient torch design
Regarding brightness, the T6 chip is one specific bin of a family of similar XM-L chips, their specs are given by Cree here:http://www.cree.com/~/media/files/cree/led%20components%20and%20modules/xlamp/data%20and%20binning/xlampxml.pdfThe maximum current Cree specifies is 3000 mA (3 A) which, according to their specs, gives 325% greater brightness than at their baseline of 700 mA, or 3.25 x 280 = 910 Lumens. From their Current vs Voltage plot, 3000 mA is achieved at approximately 3.35 volts; I write approximately because the characteristics of each chip varies somewhat from the average values given in Cree's specs.At any rate, 17,200 / 15 = 1147 lumens can be achieved by slightly overdriving the chips beyond the stated 3000 mA maximum using a slightly larger voltage than 3.35 V and apparently that is what is being done here. The downside of overdriving LEDs is that they have a higher probability of burning out and their lifetime as usually defined by 30% loss of light is shorter. The upside is to simply use the battery voltage; the batteries are arranged in parallel to help drive the 50 Amps or so required by the LEDs. Use of IMR batteries will ensure sufficient current...if your flashlight seems dim check the battery type that is surely the problem. My point here is that the spec comes from more complex designing than just multiplying 1000 lumens by 15.Evidently their final design here fell short of the desired voltage because I measured almost 14,000 lumens instead of 17,200 using a Goniophotometer which, compared with a reference Integrating Sphere, is very accurate (less than 10% error). Using a lux meter (light meter) with the usual assumption of spherical radiation will lead to large error. This procedure is fairly accurate for incandescent light bulbs, as they radiate fairly uniformly, but is is very inaccurate for anything focused such as a flashlight, unless one already knows the precise beam pattern and has integrated it numerically. In any event, this measurement provides proof that the flashlight is very near specification and not a factor of two or more dimmer, as some reviews claim. All in all its an awesome flashlight!With 50 Amps and about 3.5 Volts, or 175 Watts maximum power, the flashlight heats up considerably on or near its lens so caution is needed even though the large heat sink near the lens body greatly helps. A set of four 26650 batteries lasts about a half an hour to an hour, depending how much dimness one can tolerate as the batteries discharge and power fades. I recommend Efest IMR batteries (mine have 40 Amp maximum discharge current and 4200 mAh capacity), they are the most reliable brand I have come across.Some credentials (for those who might possibly question them):Patents related to being the inventor of LED Light Strings (Christmas Lights)https://www.google.com/?tbm=pts&gws_rd=ssl#tbm=pts&q=mark+r+allen+fiber+optic+designsPhD Dissertation (Moore School of Electrical Engineering, University of Pennsylvania)http://repository.upenn.edu/dissertations/AAI8908299/
Trustpilot
3 weeks ago
3 days ago
