Surefire K2 KROMA & KROMA Milspec

Flashdark

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Sixpointone,

Yes sir. I plan to do a similar test on the K2MS when I receive it. I am currently #20 on the list at Spyder Tactical (Tacticalsupply.com) with Steve Fergeson (Sp?).

RadarGreg,

I tend to agree about the design of the light. I will be VERY curious about the runtimes vs. useful power output of the 4 different color positions. It is beginning to be fairly obvious that there are substantial inefficiencies (loses) in the regular K2 Kroma head. I guess that this is to be expected with the design complexity involved but it's still a little disappointing. I am hoping for an improvement with the MilSpec version, that will give better runtimes.

I very much appreciate your input on the K2MS runtime in "High White". The temperatures are encouraging as well as 1 1/2 hrs. at max. power and 4 hrs. of total light in this position. Thank you. With your permission, I will include various aspects of your input in the test report, not only from this thread, but from the battery thread over in the LED forum.

Flashdark sends.
 

LED61

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In conclusion the Kroma can be run at high beam for the full duration of the batteries, and the runtime is indeed the advertised 1 hour 30 minutes by Surefire, and not hot enough for damage to the head.
One last question, if one holds the light in the hand body temperature is at 98.5 F, after 100 degrees is pierced to the upside would the hand holding the light act as a heat exchanger and actually cool the light? I´m asking this because someone on a previous post mentioned the hand holding the light would contribute to heat.
 

Flashdark

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LED61,

Indeed, welcome news about the probability of "continuous-duty" in "High White Only" mode, but be darn careful about the heat generated by the "combo" settings of "High White" + "something else".

In answer to your second question, yse sir, I assume so. Anything touching the light, that is cooler than the light, would have to transfer heat away from the light. This would be especially true with blood circulating throughout the hand, like the cooling fluid in a radiator. Just armchair thermodynamics and assumptions on my part.

Hope this helps,
Flashdark sends.
 

Geogecko

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LED61 said:
One last question, if one holds the light in the hand body temperature is at 98.5 F, after 100 degrees is pierced to the upside would the hand holding the light act as a heat exchanger and actually cool the light? I´m asking this because someone on a previous post mentioned the hand holding the light would contribute to heat.

This comment?

This of course, assumes that no one is holding the light, which tends to make the light hotter, since there is not a heat sink source to reduce the temperature.

I should clarify that, what I meant was, that since no one is holding the light, it will get hotter, because the body acts as a heat sink (once over the 98.6F, of course).

I can see how my comment could be misinterpreted. You have to read it in context to what I was talking about, but then it's still hard to really know what I'm saying...might have to go edit that.
 

Flashdark

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Geogecko,

I heard a great line that perfectly lampoons the confusion:

"I'm not sure that I think I understand all I know about what you just were alledged to have said!"

Flashdark sends, I think....
 

:)>

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Flashdark said:
Goatee,

I can't believe you baked a $300 flashlight in the oven at 350'F!

As to your earlier question, I have never left my L4 on long enough to even remotely approach the heat level reached on the K2 in the first test (and I never will). I have heard that it will get pretty hot after a while.

LED61,

You are most welcome sir.
Flashdark sends, stunned!

I just checked back in and realized that my joke may have been taken seriously. I was being a little sarcastic about the heat that the LED produced.

Oops:grin2::grin2::grin2:

-Goatee
 

LED61

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The light works perfectly on BS 17650 rechargeable...for over two hours on high beam. I have updated my post above.
 

umc

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Hey all,

Does anyone know who has the regular Kroma in stock?

I just ordered one from optics HQ and then got an email saying they didn't have any in stock.

I canceled that order and called Surefire and they were on back order as well but said the word is that they're supposed to get more about the first of November so I placed an order with them. That date isn't guaranteed though.

So, anyone know who does have them in stock now?
 

MKatzpp

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so this is my first post. i monitor this board constantly and love reading what most of you have to say. but unlike most of you flashlight-philes i dont want a zillion different kinds of flashlights--just the best of the best.

i actually had almost ZERO interest in high end flashlights until about 8months ago. i always liked getting maglights for xmas or little keychain lights to help me tinker around the house. the truth is, i really had NO clue what was out there. after doing research for about a month i jumped into getting a streamlight strion. it seemed to be the most powerful light in its size and the range was amazing. some guy at copquest spent like an hour talking to me about what i wanted it for. for me i have only 2 uses, tinkering around the house and walking/hiking at night with my dog. so the strion it was...

after spending $99 on it and 2 chargers i was a happy camper. but not for long. once you get a taste of the good life you always want more. now i'm not one that needs to count pennies so if i want something i buy it (and lie to the wife about what it costs) so to me $99 was a lot for a flashlight, but not very much in general and not a lot for something of high quality. so after more research i decided to buy the ultrastinger so i could see 1000 football fields away. i figured since i had the baby (strion) the daddy would be even nicer. as with the strion the beam was well focused and had an amazing throw. so i again, was content for a while...

until may, when i decided after reading about the surefire U2 as being the most versatile and high quality light out there. after a good month of reading up about it i decided to brightguy the light for $279ish but when i got it i was SO disappointed. the light itself didn't shine nearly as far as the strion and seemed to generate only as much as the strion up close. so my conundrum was, "how in the world was this a better flashlight, especially for 3x the cost?" additionally the beam had a donut hole (that everyone wrote about in reviews). so i called surefire and figured i would keep it for close to the 30days brightguy had for returns and see if it grew on me. unfortunately for my wallet it did grow on me. my initial impressions were pretty far off. the beam itself is pure white and amazing. it illuminates a wooded area with an amazing focused beam plus a great secondary (spill) area. basically it would light up 3 walls of a room as opposed to JUST a straight shot beam (strion). and of course its usefulness with the low settings makes it a much better light to help fix things. i dont need to be blinded by 80-100 lumens when 5-15 is just perfect for fixing something.

so of course i decided to hold onto it and what a great toy it is. and for those of you who love the idea of rechargeable lights (as i initially did with the streamlights) their usefulness is limited over longer periods of time. the surefires just keep pumping out more light for longer plus a quick battery change as opposed to a long recharging process. so again i was happy...for a bit.

it wasn't long after that i started reading about the surefire kroma. now for me, as this point, quality and uniqueness is really all i want. there comes a time when you dont need anymore flashlights to get by in day to day life. i'm sure most of you would disagree, but that's just a flashaholics take. reality is...1-2 versatile flashlights is perfect for about 99% of occasions. so for me the kroma was more of a neat toy rather than something useful.

i again did a TON of research, but the kroma was still months away from being readily available so the research was thin. after about a month i decided $300 for another flashlight might be pushing it with my wife. her questions about "is that ANOTHER flashlight in a 4 month period" and "how much did THIS one cost?" were getting too close together. so i let the matter drop until about a week ago. it appeared as if they were out there and being shipped around so after seeing steve from tacticals ad about 20% off to cpf members i couldn't resist any longer.

it arrived today and i'll give some initial impressions based on house use in the daytime and using it in darkness in the bathroom only. i will put a + next to the number when i feel its good and a - when i feel its a negative...obviously


1)+the low white beam is better than the u2 lowest setting. its probably half as strong making it more usable for everyday non-blinding use.

2)-the high beam white is somewhere in the u2 4-5 setting neighborhood. its hard to pinpoint exactly how bright it is comparatively. but its far from the u2 6 setting. for me this is somewhat disappointing. personally i'd like a massive power output to illuminate the woods 800 feet away, but that's me. one thing i've learned about flashlights is that 98% of needed light can either be VERY dull or VERY bright. i say this because there are very few times i use the u2's 2-5 settings. so for my own personal use and findings something should be like 10lumens or 200 and that would take care of almost every problem out there. bottom line, i'd like the white high to be probably double what it is now.

3)+both the blue and red are very nice, however i find the 2 different settings (high and low) to be of almost no use. this is a tough balance for the flashlight because the milspec one uses 4 LEDs for each of the 4 colors whereas this uses 8 leds for the 2 colors. the red/blue lows dont seem to be useful and could've been replaced with a different setting of some sort. of course i know this to not be possible since red/blue high each use 8 leds so there wouldn't be room for anything else.

4)+the quality is like every other surefire. good solid build, strong feel, easy grip, etc. the one gripe i have about surefire is i feel they might be TOO well built. the truth is the metallic sandpaper grip makes it impossible to stick in your mouth. i'm sure you're all like "WHAT?" but think about how often you're holding something in one hand, a screwdriver or wrech in another hand and you've got the flashlight in your mouth trying to make what you're doing easier to see. anyway, whenever i do that with a surefire it feels like my tooth enamel is being ground away by the metal grooves. the weight seems a little off too. almost seems too light and less strong than the u2. has a slightly less quality feel to it. obviously its not of lower quality tho.

5)-a lot of people dont like the click cap to turn the u2 on. personally i LOVE it. i dont like having to turn the bottom to keep something on. grabbing a flashlight and using it with one hand to activate is great. its quick and easy. this one has a momentary on but you MUST turn it to keep it on. not really a fan. its one of the reasons i wanted a surefire in the first place. the strion must be turned and i wanted to see how other things went. i like the tactical aspect of momentary on or perma on using the click button. thats just me maybe. all the aspects of use take a little getting used to. you turn the bottom for on. turn it more for higher white. push the button for low on, push it more for high on. its just too much for that bottom to do. its a little annoying to have to pay THAT much attention down there. and of course low light vs high light momentary on takes some exact pressing for periods of time possibly. just not a fan.

6)+the indicator clicks (to choose, blue/red/white) as opposed to just turning on the u2. i like the easy swivel of the u2, but i can see why this needs to be different. you need to know exactly what click you're on and it needs to stay there. so no big deal imo.

7)+the beam itself is a square up close. again no big deal. more importantly there is no donut on this light. its seems to be fairly uniform. the spill is a little weak too. on the bright side the beam is even more white than my u2. i wasn't sure that was possible but this appears to be more of a purer white. i love the more white color this seems to be.


a lot of my interpretations and reviews are subjective obviously. they should be taken with a grain of salt for a few reasons. 1) i hated the u2 when i first got it and now i would probably jump off a cliff if it was taken away from me or i ever forgot to bring it out at nighttime or if i ever went on vacation without it. 2) i haven't had a great chance to test my new light yet. shining on walls and in a bathroom doesn't do a flashlight justice.

i will say with definitive certainty the low light is just more useful than other high output flashlights for working within a 2-3ft distance of your eyes. for now i dont have any beamshots and cant think of anything else to write.

as for recommendations. for now i can say 100% that the u2 is a better all purpose light. without being a scientist or a hunter the red/blue is more of a novelty meant to calm a 30yr olds need for a new toy, rather than something of extremely high necessity. i will hopefully repost later with updates.
 
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MKatzpp

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i also have a follow-up question...


i guess since i'm relatively new to flashlights, what exactly is a "18650 cell" battery? how big are they, what would the output difference be in either a kroma or a u2, etc. does the flashlight need modifications in order to use the 18650? can someone fill me in on the details/specifics? can i just buy one or two and plug it into one of my 123A flashlights?

thanks in advance.
 

LED61

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An 18650 cell is a li-ion rechargeable cell that holds anywhere from 1800 to 2600 mah capacity. That is the big attraction as it can be used on some U2´s but no go on the Kroma. The 18 in front stands for 18 mm diameter (fat cell), and the 650 means 65 mm in length. By comparison a primary CR 123 would be a 16400 cell, 16mm diameter, 40mm length. You can fit a 17670 rechargeable with 1500 mah capacity into the Kroma though, at least in mine. i have found this to work just fine for a long period of time--over two hours on high beam. The output is unchanged from primaries. Do some research in this forum before you start messing around with rechargeable batteries, or other lithium batteries for that matter. lithium batteries can explode if overdischarged, and you should never mix used with new batteries in series in a flashlight.
 

Chronos

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LED61,

Did you have to do anything to your Kroma to make it work with the 17670? The reason I ask is I have the latest 17670 from AW and it doesn't work. Do I need to extend the spring in the tailcap a bit, or is there a way to position the cell so it works? Any input would be greatly appreciated.

Thanks
 

LED61

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Chronos, my 17670 is from Kevin at batterystation.com, so diameter may vary slightly. The battery goes in very tight. It is necessary to open the light from both ends and push down from the positive side toward the tailcap end. For some reason the battery will not go in if pushed from the negative side. And, you must do the final gentle push with led head screwing it back in so that positive contact is assured in this way. If you push too far, the battery will be so tight that the negative end will not be able to push the battery to ensure positive contact. I have found that the light runs great with this battery and actually a much cooler for long periods of time. Good luck
 

:)>

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Chronos,

I had intermittent success with the 17670's. Some times they would work and sometimes they did not. I had better success with the batteries that did not fit so snuggly that they did not move easily in the tube.

One way to reduce the diameter of the battery is to take the coating off of it and replace it with a layer of packing tape. This reduces the diameter of the battery a little and it makes it so that it can slide in and out easier.

It will definately work, the question is how to get it to work consistently.

-Goatee
 

Flashdark

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To All:

Testing has been completed for the K2 KROMA in Post #40. Minor odds & ends will be added in the future, if appropriate.

Awaiting the K2 KROMA MilSpec for the side-by-side comparison. That review will be posted in this thread and will follow the same format.

Hope some of this helped,
Flashdark sends.
 
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umc

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MKtazpp,

Boy that was a long post. ;P :D

Anyway, I read it all and hear ya.

I have many Surefire lights and love them all. My U2 sits next to my bed and gets up with me in the middle of the night, it reads in bed with me, etc.

Now it's been great for that and I love it although I've had times when I felt low was too high. My Kroma came in today and the testing has begun. I think it will work better for me at night as a low light, umm well light. It will be better for not disturbing my wife next to me sleeping if I'm reading in bed with it. I'll find other uses for the red and blue as well.

So far I do agree that I wish high white was a lot higher about x2 like you said. I knew it was 50 lumens when I bought it so that's fine, I accept this. I rarely set my U2 to 6 only if I was out and about on the town or in the woods but I have other lights for that, the U2 is primarily at home. Thing is because it's so functional I like to use it else where. Oh well.

So going forward I like the Kroma so far (only 4 hours to this point) and know it will work out well for what I have intended for it. Now on my wish list though is a Kroma that goes to 100+ lumens on high and a clicky cap.

Thing is I can't turn the tailcap with one hand without turning the "light selection" dial.
 

rgp4544

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TOY????? A lot of these comments have steam coming out of my ears.

Sometimes I wonder why people buy stuff they don't need...and I try to ignore reviews of lights from people who didn't need the capabilities but for some bizarre reason had more money than brains and had to run out and buy a new toy. Don't confuse compulsive shopping with need.

Keep in mind the Kromas were designed to meet a specific work related need and the need exists, it isn't just there for hobbyists to have a light with pretty colors. Some of us have an actual need and really aren't interested in buying another light unless it meets a specific need. Personally, I've ordered a Kroma Mil Spec to meet a specific set of work requirements.

Richard
 

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