KDLITKER C8.2 Cree XHP50.2 White or Neutral White or Warm White 2600 Lumens 5-Mode LED Flashlight uses of 1x18650

TL;DR:For $35, this light delivers damn impressive performance. you're getting is something that was engineered to output the absolute maximum possible amount of light from this form factor whist cheaping out on everything else. The biggest issues with it regard safety, there are no built-in safety features. This WILL damage your 18650's if you are not careful. Inserting the cell them backwards will cause a short and damage both the battery and the LED driver (no reverse polarity protection). Additionally, the light features no under-voltage cutout but rather just dims as the battery gets low, below 3v. The light is also capable of catching things on fire and will overheat if on max for too long. There is no temperature cutoff.For optimal performance, be sure to use a good quality battery. This light demands 6A from a single cell when in turbo. The battery must specifically be rated for high current (10A) discharge. Expect a maximum capability of between 400 and 600 Lumens and short runtime with a cheap or old/recycled battery.What impressed me:This light appears to use a genuine CREE XHP50.2 LED, which is excellent! Also it appears there was some attention paid towards optics, as it appears the glass window has an anti-reflective coating on it. From an electrical standpoint, this LED is more complicated to power than more conventional XML lights. Where XML-based lights can get away with direct-drive and PWM driver implementation, this LED requires 6V. This means a more complicated boost converter topology is required. The benefit of using a switching converter includes greater efficiency than a direct-drive/PWM method and there is no low-frequency flicker when in the non-turbo modes. I was initially concerned about how much the driver can pull from a single cell, but after measuring close to 6A of current draw on turbo, I was very impressed! Keep in mind this current includes the additional shunt resistance and consequent voltage drop from my multimeter, too! Assuming the voltage seen directly at the boost converter is 3V with a fully charged battery (assuming ~200m‎Ω resistive losses?), we are delivering close to 18W to the driver, and due to inefficiencies, a bit less (guesstimated 80% efficiency = 15W?) to the LED. But I expect this light to perform best with battery rated for high discharge (10A or greater) The cheap and otherwise great 3.4AH Panasonic cells are rated 5A continuous max, and while they can power this light, you will not get the maximum brightness, and you will be pushing the cells beyond the maximum ratings. This light will dissipate close to 20W when in turbo, so expect it to get hot!What didn't impress me:The shipping time is atrocious! It took an entire month to receive mine, so do'nt expect to receive this light soon after buying it. As for the light, I found that the modes are quite buggy (discussed above). I think the maximum output is really 1800LM (ish), even using brand new 20A samsung INR batteries. The "2600LM" rating is the maximum capability of the highest binned XHP50.2 LED's, and ignores optical losses and assumes the tiny boost converter and single 18650 can deliver the 18W required to the LED. While I believe this does use a genuine XHP50.2, don't expect it to be binned high. I ordered the "neutral white" option hoping it would also be high CRI, but I don't think that's the case. Also, the aluminum 'C8' body is particularly cheap feeling. It feels light and airy, The anodizing on this is very rough feeling, almost like a chalkboard, and the diamond knurling is flat and only exist for looks. For these reasons, this light isn't perfect. But in all honesty, I think at this price point, all of these nitpicky issues can be forgiven, and the light overall delivers an excellent value proposition!Potential HACKS:When I get around to it, I plan to reverse engineer the boost converter and see if I can create custom firmware for it. Hopefully I can change the way the modes work in the more conventional manner. To improve output and increase efficiency, the steel springs can be easily hacked to have a bit of copper wire connecting the tip to the PCB on both ends. This will eliminate a great deal of the parasitic resistances in this light, and unlike the direct drive lights, this reduced resistance should actually lead to _increased_ runtime due the the boost converter needing to draw less current in attempts to maintain constant output power. Additionally the power switch _may be replaceable with one of higher current rating, although from my measurements, the included one is already pretty good.

Update 07-24-2022: So here we are 4.5 years later and I still love this light and it's going strong. I came back to see if it's still available because I want a second! It seriously has become one of my favorite lights...and I have a lot. LOL Probably because I always loved the C8 form factor. I see some people complaining about output. I can without a doubt say to Mr. "950 lumen at best": Buy a proper battery! Those junk bargain 18650's are lucky to supply 2 amps of current!! This light pulls 5-6 amps without trying hard! Name brand, (Samsung, LG etc) high output 18650'skWow, the C8 just totally lends itself to the XHP50! Perfect host for this LED. Everything that is great about the C8 is magnified with this chip. The hotspot is a little larger than the XML based C8, but not because the chip is bigger, simply because of more output. Just like the XML C8 it has a great balance between throw and spill - just more of it. Clean output, no artifacts etc. I have not investigated if this is a genuine cree chip or a knock off...BUT, if it is a knock off, it's a good one as the tint (NW) is good, and it seems efficient with heat and run times matching it's output. With a LG HE2 it's pulling on average about 5.5amps at the tail which is right in line for what this LED is supposed to do. (17-19 watts.)Quality of the light is fine. Nothing super fancy, but not bargain bin cheap either. Tail switch, springs, threads, glass etc all good quality. Best bang for the buck you will find online...period.

This is by far the brightest flashlight I have ever seen it puts spotlights I've used to shame. If you need a super bright flashlight this is what your looking for. It is fairly compact for being as bright as it is and variable brightness adjustment by pressing half a click in the switch makes this a flashlight for every situation. My only concern is how hot this gets during extended use 5+ minutes of continuous use at max brightness. I'm sure it will get hot enough to de-solder the connections or cause burns so use responsibly.

I don't think you can get more light from a one 18650 battery flashlight. The neutral version is a great color, no blue, the battery lasts quite long. It is not awfully expensive. I dropped one and it quit, and the Company sent a new one without argument, and I am happy with the Company and the light after a year. How much light? Think your car headlights on bright! Really.

Love the brightness, doesn't have the farthest throw though. Heats up pretty quickly.

This light is advertised as a 2600Lm light. I put this light next to my 950Lm light and there is no difference. Yes, I did have a fully charged battery installed.

When I first received this item it was one of the best flashlights I have owned. But it only lasted a couple of weeks. I contacted the seller and they agreed to put a new switch in the mail but it never arrived. The quality of the product is very poor and so is the seller's support.

I put in a high drain 18650 and this thing lights up the universe, a light rocket in your pocket!