"K2 12W Wide Projecting LED" from Fifthunit: *not a K2* (beamshot & runtime)

"K2 12W Wide Projecting LED" from Fifthunit: *not a K2* (beamshot & runtime)

[UPDATE 10/20: It's confirmed the 18650 version of the Vika "12W Wide" LED from Fifthunit is actually a LuxIII running direct drive. The 2xCR123 version is indeed a lumiled K2, but not the 18650-specific version. Fifthunit has promptly delt with this issue, and revised their descriptions accordingly: Fifthunit 12W "Wide" Vika]


I just received the new 18650-version of the K2 wide-lens light from fifthunit, and am pretty impressed so far.



Quality of construction is better than I expected for such a cheap light. Thickness of the bezel is good, and anodizing is smooth throughout. There seems to be a limited number of screw threads on the head-portion of the body, but this doesn't seem to affect it much. Oddly, the spring is soldered directly onto the head PCB, thus making contact on the positive battery terminal. Not the highest quality here, but does the job so far.



Light is labelled "CHARGE.B-18650" on one side, and "POWER-12W" on the other. There's plenty of room inside for a protected 18650 - this is actually one of wider internal diameter bodies that I've seen.

The tail features a 2-stage reverse clickie that has good tactile feel (sequence is high-off-low-off). Overall hand-feel is very nice, and it sits comfortably in the palm being about half an inch shorter than a standard minimag.



Popped in a AW protected 18650 (3.7V Li-ion, 2200mAh), and was blown away by the beam. According to my light meter, on high, it slightly exceeds the throw of my 3W-LED upgraded 3-D cell Mag focused for maximum throw.


(3D Mag with 3W LED upgrade on the left, "12W" K2 Wide-Projecting on the right)

Note that the spillbeam is fairly wide, thanks to this new larger reflector (with 3 interesting "dimples"). Overall output seems to be about the same as the 3W 3-D Mag. Not bad for such a little light!

On low, the hotspot is still pretty bright: about 20% brighter than my Fenix P1, according to my lightmeter. But subjectively, overall output is definitely less than the P1 at this point.

I haven't had a chance yet to do detailed output comparisons or battery runtimes (I'll post more when I do), but so far this little light is off to a good start!

UPDATED: runtime graph below - pretty impressive at 2hours 10mins to 50%. Note the spike at 1hr, where the light started to flicker for about 30 secs. It recovered, and was fine from then on. There is always some minor noise on my runtime plots, since they aren't done in complete darkness.

Re: K2 "12W Wide Projecting LED" from Fifthunit: First impressions (with beamshot)

Sounds promising...Where can we get them?

Re: K2 "12W Wide Projecting LED" from Fifthunit: First impressions (with beamshot)

http://www.fifthunit.com is the home of the K2 "12W" light.

Re: K2 "12W Wide Projecting LED" from Fifthunit: First impressions (with beamshot)

Hi Selfbuilt, finally you've reviewed the light I've been wanting to buy!

Thanks for the review.

Can the LED assembly be accessed easily? Does this light use a regulating circuit or a resistor?

I look forward to your reply.

Tachy

Re: K2 "12W Wide Projecting LED" from Fifthunit: First impressions (with beamshot)

Could you kindly post the lux readings @ 1m?

Thanks!

Re: K2 "12W Wide Projecting LED" from Fifthunit: 1st impressions (beamshot & runtime)

Updated the first post to show runtime graph.

I believe this light uses a resistor, like pretty much all of the "7W" and higher China-made lights (in this case, different resistors for 18650 version and 2xCR123A primaries version). The LED does not seem easily accessible, but I haven't tried disassembly.

I can't give precise lux readings, since I use a home-made light meter (CdSe resistive cell hooked up to a DMM). I can only evaluate relative differences between lights, although my values typically correlate very closely with Quickbeam's FlashlightReviews.com (r=0.97 for ~20 or so light we have in common). Unfortunately, in this case, my Mag3W seems a lot less bright than Quickbeam's sample, so I can't give you a reliable comparable. Re-running the comparisons (including night forays with the lights), I would say this "12W" K2 is actually not quite as much of a thrower as the Mag3W. But it's certainly a lot more than my Streamlight ProPolymer 4AA Luxeon.

Re: K2 "12W Wide Projecting LED" from Fifthunit: 1st impressions (beamshot & runtime)

Thanks for the excellent information. I've placed an order for the light already

If you ever get around to accessing the LED assembly please let us know.

Tachy

Re: K2 "12W Wide Projecting LED" from Fifthunit: 1st impressions (beamshot & runtime)

Yes, please let us know what you think.
The runtimes didn't look that good on the website but your runtime graph looks pretty good... :thinking:

Re: K2 "12W Wide Projecting LED" from Fifthunit: 1st impressions (beamshot & runtime)

I suspect the runtime difference is in the battery - I'm using an AW protected 18650 from Lighthound (3.7V, 2200mAh). I suspect the no-name "3.6V, 1800mAh" used by fifthunit is not very high quality. Incidentally, My 4W CPF multi-level light from Wits' End gets over 4 hours on the highest setting with this AW battery. Clearly, these AW cells rock. :rock:

My only concerns with the light so far are heat and occasional flickering issues. The unit is one of the hottest lights I have when run under prolonged operation, but nothing unbearable so far. Flickering is not uncommon on these cheap light, and seemed to clear up with a good cleaning of the contacts and threads. But you'll notice the flicker episode in my runtime plot at 1 hour. Could have been heat-related - but the unit had reached peak surface temp around 35-40 mins, and I had an oscillating room fan going on it from that time on. Oddly, the flicker resolved spontaneously on its own, and the rest of the run was un-eventful.

The head seems pretty well closed up, and I'm not inclined to risk damaging anything to satisfy my curiousty ... sorry guys

I'm sure a few more of these must be in the hands of CPFers by now - looking forward to seeing their experiences (especially someone with a calibrated lightmeter).

Re: K2 "12W Wide Projecting LED" from Fifthunit: 1st impressions (beamshot & runtime)

It'll run ok off of two primary CR123s? If you've tried it, is it brighter?

Re: K2 "12W Wide Projecting LED" from Fifthunit: 1st impressions (beamshot & runtime)

I believe this is made like the wolf eyes....the batteries go in negative end first....

Re: K2 "12W Wide Projecting LED" from Fifthunit: 1st impressions (beamshot & runtime)

Lighthouse one said:

I believe this is made like the wolf eyes....the batteries go in negative end first....

Click to expand...

No, the positive battery terminal goes against the spring in the head, and the negative remains at the tail. If you reverse it (which I naturally did when I saw the design too), the light won't come on. At least I know now there's polarity protection built-in :lolsign:

As for CR123 primaries, no, I haven't tried them. On most lights that take multiple battery types, 2xCR123 typically gives you brighter performance over single 18650. But this version is design solely for a single 18650 - and fifthunit specifically recommends against trying any dual battery setup, as it may in fact blow the bulb. Given that the 2xCR123 version of this model seems dimmer on the fifthunit run tests, I'm guessing they really have optimized the 18650 version for max performance with whatever resistor is in there. On the flip-side, I imagine the 2xCR123 version could probably take 2x3V or 2x3.6V Li-ions and run brighter (probably as bright as this version, if they've done it right).

Sorry guys ... I'd normally be willing to take one for the team, but I like this light too much to risk turning it into a doorstop. Any other willing guinea pigs out there with this light?

Re: K2 "12W Wide Projecting LED" from Fifthunit: 1st impressions (beamshot & runtime)

Looks like a nice light and well made at that. Dae also has them --> http://www.qualitychinagoods.com/super-bright-2xlir-rechargeable-lumileds-p-476.html

and

http://www.qualitychinagoods.com/1x18650-rechargeable-recommended-p-479.html

Re: K2 "12W Wide Projecting LED" from Fifthunit: 1st impressions (beamshot & runtime)

I have had better customer service with fifthunit.com, and better prices.

DUQ said:

Looks like a nice light and well made at that. Dae also has them --> http://www.qualitychinagoods.com/super-bright-2xlir-rechargeable-lumileds-p-476.html

and

http://www.qualitychinagoods.com/1x18650-rechargeable-recommended-p-479.html

Click to expand...

Re: K2 "12W Wide Projecting LED" from Fifthunit: 1st impressions (beamshot & runtime)

FlashKat said:

I have had better customer service with fifthunit.com, and better prices.

Click to expand...

I've bought from both, and have been happy with the service from both. I've heard it suggested around here that Dae pre-screens the lights from his suppliers, to help insure quality. Don't know if that's true or not, or what Fifthunit's policies are in that regard. So far, no complaints from either.

What I can tell you is that Fifthunit's keychain lights (currently on sale for $5 for 10) must use the older LEDs, as they are only about 2/3 as bright as the ones I've bought from Dae ($8.20 for 10). They also have a much stronger purplish tint. Sometimes you get what you pay for.

Re: K2 "12W Wide Projecting LED" from Fifthunit: 1st impressions (beamshot & runtime)

You do get what you pay for...When I bought 2 7 watt Golstons and one failed immediately Dae would not warranty it, because he kept wanting to blame me for it failing. I guess you are right about you get what you pay for including customer service.

selfbuilt said:

I've bought from both, and have been happy with the service from both. I've heard it suggested around here that Dae pre-screens the lights from his suppliers, to help insure quality. Don't know if that's true or not, or what Fifthunit's policies are in that regard. So far, no complaints from either.

What I can tell you is that Fifthunit's keychain lights (currently on sale for $5 for 10) must use the older LEDs, as they are only about 2/3 as bright as the ones I've bought from Dae ($8.20 for 10). They also have a much stronger purplish tint. Sometimes you get what you pay for.

Click to expand...

Re: K2 "12W Wide Projecting LED" from Fifthunit: 1st impressions (beamshot & runtime)

I ordered the 2xRCR123A version of this light from Fifthunit, before they posted the runtime/output charts where the 18650 model seems to blow away the 2xRCR123a model. I had supposed that the 123 model would have greater output than the 18650, at the expense of runtime, and that suited me fine.

I wasn't too happy after seeing the charts, and expressed that to Kai at F/U. He kindly responded that the test results, which he'd duplicated at least once, had surprised him also, and that I could return my light for refund or exchange after it arrived if I wasn't happy with it.

A few days later my light arrived, and I am now confused indeed. Here are my findings so far:

1) The body tube is actually wide enough for an 18650, and so requires a wrap of paper around the slimmer RCR123As to minimize battery rattle!

2) There is no apparent Low/High---light only has one level??!!

3) Runtime on 2xRCR123As (750 mAh) is ~28 minutes till the protection circuit in the cells kicks in.

4) The light stays at almost the same output the entire 28 minutes. I did not see the output drop quickly as shown in Kai's graphs.

5) Throw is very good---noticeably better than the 10w "Glimt", which itself is quite good. The hotspot is smallet than the Glimt (F/U might want to re-think its description of a "wider" beam). I imagine the large turbo bezel is responsible for the increased throw. Using Quickbeam's throw figures, I would guess it's ~low 80s---very impressive for a relatively small lux light.

6) There is a small "donut" when focused up close, but at a little more distance it is not noticeable. Tint is white.

7) The light does get hot on RCR123As, but not unbearably so.

8) This model also runs on an 18650, but not nearly as bright---a little better throw than the Glimt on "Low" but noticeably less than the Glimt on "High". I would guess maybe low 50s in Quickbeam's throw numbers. Heat is not an issue on an 18650. Haven't done a runtime test on an 18650, but based on higher mAh and lower output, I'm guessing it'll run and run.

9) Build quality is good. I agree with selfbuilt's observations.

In sum, this is a hell of a lux thrower, taking full advantage of the turbobezel, large smooth reflector, and K2 (?) emitter. The flat discharge is a nice surprise.

The lack of a (noticeable) High/Low is a negative. A Low setting would be useful, given the issues of short runtime and heat.

The tube size has me baffled. I was beginning to think I received the 18650 model by mistake, but both selfbuilt's and Dae's photos clearly show I have the 2xRCR123a model. I'm thinking that maybe this is like the Peak CPF Special/Ranier, that is a barnburner with one type of battery, and a lower output runtime champ with another.

Finally, whatever type of critter this is, it's an interesting and impressive light for $27 shipped!

Re: K2 "12W Wide Projecting LED" from Fifthunit: 1st impressions (beamshot & runtime)

Hi AFAustin,

Since this light seems to be a direct drive using a resistor the output would be a lot lower on a single 3.7 volt 18650 compared to two 3.7 volt RCR123's. The value of the resistor in the light is chosen to drop voltage from 2 X RCR123 batteries.

To make the light brighter with a 18650 battery you will have to change the resistor to a lower value.

Cheers
Tachy

Re: K2 "12W Wide Projecting LED" from Fifthunit: 1st impressions (beamshot & runtime)

Tachyon said:

Hi AFAustin,

The value of the resistor in the light is chosen to drop voltage from 2 X RCR123 batteries. To make the light brighter with a 18650 battery you will have to change the resistor to a lower value.

Click to expand...

Agreed, that seems to be exactly what was done - one high resistor for the 2X battery model, and low resistor for the single 18650 model. This is why you can run a 18650 on the high resistor model (with lower output), but you can't run 2X battery setups on the 18650 model without risking frying the light.

Judging from AFAustin's results, it sounds like they've matched the resistor/output pretty well for the two models. My 18650 version also seems to throw on high around Quickbeam's 80 mark (given the approximation of my Mag 3W 3D).

Bummer about the lack of low/high on yours - that's always a major selling point for me. Judging from my light meter and Quickbeam's results, I'd say mine throws around 40 or so on low.

So, the advantage of the 18650 model is apparently longer runtime than the 2X battery model, and the advantage of the 2X battery model is the flexibility to run all battery types (although with much lower output on single cells of course)

An all-in-one circuit driven light would of course have been a lot nicer, but what do you expect for $27 shipped, eh? :laughing:

K2 "12W Wide Projecting LED" from Fifthunit: no K2 inside !!!

Got my light from Fifthuint today and couldn't resist to take it apart.

There is no Lumileds K2 inside !!!

I found a LuxIII on star, direct driven without any resistor.

Initial current on 18650 was 1,25 A.

Yes it's bright and has a very tight hotspot, but it's not a K2 light.

Here is what i got:




O-ring, bezel, retaining ring, plastic reflector 40,5mmx19,1mm, glas lens 41mmx2mm

Tailcap and content