KL4 head Vs Reflectorized, Seouled KL1, differences?

As many here know, my absolute favorite light, and the one i reach for 95% of the time is my ROK-modded KL1-SR, a standard TIR optic based KL1 that ROK dropped a Seoul P4 emitter in, kept the drive level at 500Ma, and walked me through adding in a McR20-S reflector

this light puts out a great beam profile, a nice bright hotspot with a smooth taper to a bright, usable spill, it leans more towards the floody side than throw, which is perfect for my needs, the ability to run a RCR-123a just seals the deal, a great light, bright, and pocketable with a great beam profile and decent runtime

I've heard rave reviews of the KL4's floody "Wall Of Light", i have a spare VG2 body, as well as my E1e body, however, i'm wondering how much of a difference in beam profile there is between the KL1-SR and KL4

how much of a difference is there?

Hi, I have the KL1 modded like yours and I bought my dad a L4 so I have used it often. The L4 is all flood, no hotspot at all and on some lights the center is slightly dimmer. some described it as a "donut" beam. Overall its a really nice flood.

If you are looking for flood, get the F04 diffuser from surefire... I did and I couldn't be more happy. it puts out a beam more like the L4.

If there was ever a thread that I could provide the answer for, this is the one! I'm so glad you asked this question, since I've never posted my beamshots before.





I own a KL4 head which I use on an E1e body with an AW protected 3.7v RCR123 li-ion rechargable battery, sometimes with a two stage tailswitch. I also have a KL1 which a CPF member opened up and added a Seoul LED and McR20 reflector (not the McR20-S, and I don't know what the difference is). The KL1 uses the same body setup.

Below is a beamshot picture, both powered by one fully charged RCR123 cell:



Below is a beamshot picture that more clearly shows the spill beam differences:



The KL1 has a brighter hotspot as well as brighter spill beam. The hotspot is tight and blends smoothly into the spill beam. Note that the spill beam is rather narrow/small, as noticed in the second beamshot picture. The KL1 has a very white tint, and not as blue as the pictures suggest.

The KL4 has a large hotspot that is not defined like the KL1. The hotspot blends very evenly into the spill beam. The spill is usefully bright (shows up rather dim in the pictures), and is also VERY wide. The beam tint is noticeably yellow, but not as yellow as an incan.

Comparison: shooting light directly onto a single object 5 feet away, the KL1 is obviously brighter due to the tight hotspot. However, when trying to light up a room, only the KL4 will succeed. The KL4 spill beam is just incredibly wide and bright for a flashlight this size.

My EDC needs are mostly indoors and close range. Shooting the light at objects less than 12 inches away, the KL1 hotspot is too concentrated. The even, smooth beam profile of the KL4 is better suited for close use, especially with a two stage switch. The two stage switch also helps overcome the KL4's heat problems when trying to use it for longer than 5 minutes.

Therefore, for indoor EDC I usually take the KL4. I also carry a G2 with a HO-9 lamp for outdoors. However, if on a given day I want a single light for all around use, I will take the KL1.

Message to all KL1/KL4 users: Get a McE2S Two Stage switch! This little mod will add a ton of versatility to your light. I bought the 22ohm version, and it creates a useable low mode (not too low) for most close applications.

Note: One of these days I will conduct a runtime test between my KL1 and KL4. I will also do an unscientific heat test at the same time, just by touching the flashlights and see how hot they get.

jlomein, thanks for the comparision shots. I have the KL4 and love its wide beam. It does run very hot after a few minutes, and I think that a reduction of mA's to the lux V emiter would cool things down and not cause too much of a loss of lumens.

Bill

So out of boredom I decided to do the runtime test between the stock KL4 and KL1 (modded with Seoul LED and McR20 reflector). Both flashlights were loaded with one AW protected RCR123 li-ion cell that had been charged and sitting without use for a week. I do not claim this to be a well run test in any way. It has many variables that are unaccounted for so take that into consideration when reading the results.

Runtime:
0 Minutes
KL1 - RCR123 cell tested as 4.15V
KL4 - RCR123 cell tested as 4.17V

After testing each cell with a DMM, I began the test.

7 minutes
KL1 - warm, tolerable to hold
KL4 - very hot, cannot hold for longer than 3 seconds

14 minutes
KL1 - marginally hot, cannot hold for longer than 8 seconds
KL4 - extremely hot, cannot hold for longer than 1 second

18 minutes
KL1 - moderately hot, cannot hold for longer than 5 seconds
KL4 - extremely hot, funny smells are being emitted

Test is ended due to safety concerns. Both flashlights are turned off, disassembled, and batteries removed.

28 minutes
KL1 - fully cooled battery tests as 3.83V
KL4 - still warm battery tests as 3.72V


I had the flashlights laying on my couch facing a wall, and since the KL4 started smelling like burnt fabric, I stopped the test after 18 minutes. I also noticed that when I opened the body to the KL1 light, it had no smell, but when I opened the body to the KL4 light, it had a foul burning smell.

In conclusion, I was unable to find the full runtime of each device. It is likely the KL4 runs down faster, judging from the ending battery voltages. I also found that in this setup, it is not a good idea to run the KL4 longer than 10 minutes. Although if used in hand, your body will probably act as a heatsink.

MacTech, glad to hear you still love it.
My new favorite light is ;

I called E1D-L. :nana:
McR-20-S + Piglet Board (50/500mA)

ROK, you did great work on this little beauty, it's never left my side since i recieved it, it's a great companion for my Aviatrixed A2

Jlomein, thanks for the beamshots, the KL4 head looks like it puts out a nice flood of light, at some point i might just have to pick up a KL4, but at the moment, i'm really loving the balanced beam profile the McR20-S puts out, a very nice balance of flood and throw

Can someone post a picture of what the KL1 looks like with a McR20S reflector? I'm curious to know how different it looks from my standard McR20 reflector. Also curious if the McR20S creates a different beam profile?

One thing I would love would be to make the spill beam wider on my KL1. I'm assuming it is so narrow because either the reflector is deep or the domed lens is having a focusing effect.

I have never seen a Seoul LED in a TIR optic KL1. I wonder what that beam profile would look like, whether or not the Seoul works well with the optic, and what change the F04 beamshaper/diffuser would make.

I don't have any pics but:
KL1 SSC + optic still all throw.
KL1 SSC + optic + F04 no hotspot and flood but not as much as with reflector
KL1 SSC + McR20S + F04 is all flood. (my favorite setup for most everyday)

I have all 2 KL1 with SSC, one with optic and one with McR20S.

Its just way better with the reflector.

sorry for not having pics

ROK, that E1D-L is cute as a bugs ear.

The KL4 does get hot just standing there running. That is reason I will probably drop off some current to my KL4.

jlomein, I was surprised that the KL1 with Seoul got so hot. I have never had one of my stock newer generation KL1's do that. Heat has got to be a result of the Seoul in your KL1. Doesn't sound right, but that has got to be the problem. Stock mA's to led in KL1 is about 550mA's. 660mA's, or so, to KL4, but it is a four die emiter-Lux V, and you can expect lots of heat with that combo in a small head. The other problem with the Seoul is that it needs excellent heat sinking, not just sitting on some artic alumina, rather sitting on anodized aluminum with minimal thermal adhesive. Of course, in your case, the heat is obviously getting to the head.

Bill

Bullzeyebill,

In regards to the modded KL1 heat generated, I have no idea. I have never owned a stock KL1, so I don't know if that runs much cooler.

After I posted in this thread, it got me thinking about what I want my ultimate EDC to be. I think I would like something more like the KL4 (wide spill beam, unconcentrated hotspot), but with a longer battery life and less heat issues. I used my KL1 last night and got frustrated by the narrow spill beam, which is a result of the bezel being so long and the LED so deep inside it.

I have seen a KL4 modded with a Seoul LED, I might look into that. Perhaps it could also have the current turned down for a little less brightness but better cooling. It should have a similar large spill beam, but probably a more concentrated hotspot.