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Thread: Feeler on modded KL4's

  1. #1
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    Default Feeler on modded KL4\'s

    I have two or three KL4's coming in. My intent is to mod them with either 1W or 3W emitters and a downboy converter.

    I intend to sell at least one of these. If anyone might be interested, let me know. That way I could mod to taste. I have some DB 700's and 1000's coming and also have some Q3J's and TWAK's.

    PM me if interested. If it makes a difference, I take credit cards via paypal now.

  2. #2
    Flashaholic* PeterB's Avatar
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    Default Re: Feeler on modded KL4\'s

    Hi Tony,

    I'm interested in a TWAK (probably DB700).
    Any idea about pricing?

    PM sent.

  3. #3
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    Default Re: Feeler on modded KL4\'s

    PM sent.

  4. #4
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    Default Re: Feeler on modded KL4\'s

    If you throw in the KL1 circuit in there I may be interested [img]/ubbthreads/images/graemlins/grin.gif[/img]

  5. #5
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    Default Re: Feeler on modded KL4\'s

    All of these KL4's are spoken for. I'll probably do more if I can find hosts at a reasonable price.

    You can post here if you're interested.

  6. #6
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    Default Re: Feeler on modded KL4\'s

    Received my modded KL4 (Q3J/DB1000).
    Wow! Very bright and white, well focused and throw almost as far as my E2e/MN03.
    Chop, you did a great (I should say incredible) work.
    Thank you.

    Christian

  7. #7
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    Default Re: Feeler on modded KL4\'s

    Christian,
    Thanks for the kind words. I'm glad that you like the light.

  8. #8

    Default Re: Feeler on modded KL4\'s

    What's the idea here? Just to get more throw because of the smaller die?

  9. #9
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    Default Re: Feeler on modded KL4\'s

    Paul,
    The idea is that you can mod the KL4 with a 1W or 3W luxeon and get the extra throw. In cases where the luxeon is driven at 700mA, you also get double the runtime. The mod also generates far less heat than the stock KL4.

  10. #10

    Default Re: Feeler on modded KL4\'s

    Why not use a KL1?

  11. #11
    Flashaholic* yclo's Avatar
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    Default Re: Feeler on modded KL4\'s

    Because a KL1 doesn't have the nice shinny reflector, some of us get sick of seeing the square around the hotspot.

    Trust me, after you see a 1W HD in a KL4 reflector you won't want to go back to a 1W HD w/ NX-05.

    -YC

  12. #12

    Default Re: Feeler on modded KL4\'s

    Good point--thanks.

  13. #13
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    Default Re: Feeler on modded KL4\'s

    yclo,
    Have you been hooked by the reflectored 1W beam too. I can't lay off of these things. In spite of the cost difference between the KL1 and KL4 mods, I've found myself going for the KL4. The beam is simply beautiful.

    paulr,
    The KL1 is a very nice and cost effective LED head. It is also very mod friendly, but the beam of a modded KL1 will never be as refined as that of a modded KL4. The KL4 also seems to be able to handle heat better than the KL1 does.

    If you are just interested in a utilitarian light and aren't worried about the artifacts associated with optics, then the KL1 is the way to go, although it does get really hot at anything over 700mA.

    Oh, with a reflector, the problems of centering associated with optics, is almost a thing of the past. On the KL4 all you need to do is eyeball it and let the reflector do the rest.

  14. #14

    Default Re: Feeler on modded KL4\'s

    Chop,

    I would be interested in a modded KL4 head. I've been so disappointed in the KL5 and KL6 heads [img]/ubbthreads/images/graemlins/frown.gif[/img] that to now have a KL4-form factor "throw" head is very enticing. Please let me know if you can provide the following:

    1. 3W (TWAK?), good bin, good color. My KL4 is pure white and I'm spoiled [img]/ubbthreads/images/graemlins/grin.gif[/img]
    2. Compatibility with the 1400mAh Pila 168S 3.6V Li-Ion
    3. Driven hard, but not insane. Max useful brightness. I don't know if a DB or BB would be the appropriate converter.
    4. If need be, I will buy the body as well, as long it is a genuine L4 body and not an E2E.

    Thanks,
    Wilkey

  15. #15
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    Default Re: Feeler on modded KL4\'s

    You will not be disappointed with a 1 or 3W in the KL4. The problem with a hard driven LED is that the forward voltage spans the voltage range of a Li-Ion. If you want full regulation, you will not get it with a Li-Ion unless it's fresh off the charger. When the cell voltage drops far enough, you will be in direct drive mode minus the schottky voltage drop. If you want full regulation, a step down converter coupled with 2x123's is the way to go. Another option is to use the KL1 circuit or a wizard so that you get full regulation with either Li-Ion or 2x123 but with the consequence of less power efficiency. I do get pretty good performance on a single Li-Ion but I keep mine topped off all the time. Remeber that at 700-1000mA, the Vf of the LED is over 4V and drawing that current from a cell will cause the cell voltage to sag some.

  16. #16

    Default Re: Feeler on modded KL4\'s

    CM,

    I am pretty much completely ignorant regarding matters electronic. Are you basically saying that there is no circuit that would provide even 30 minutes of regulated output for a 3W? Wouldn't the native KL4 circuit or one of that type do the job? Right now I get almost 40 minutes regulated out of my L4/168S.

    I just don't understand the difference between buck, boost and the Madmax/BadBoy/DownBoy boards. Surely one of these must fit the bill? I guess I just want an "L5.5-ish" type throw option. I probably would not run it very much, but woudl do so on my L4 body.

    Thanks for enlightening me.
    Wilkey

  17. #17
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    Default Re: Feeler on modded KL4\'s

    Cris,
    How have you been faring with the Pilas in a buck circuit situation. I've found that I can't even notice it when the circuit drops out of regualtion using a pila. It seems that when the circuit drops out of regulation, the Pila still has plenty of juice to keep the light running bright.

    I may have to test this more thoroughly.

    I have a KL4 modded with a DB1000 sitting on my bench right now. Later on, I'll turn it on and let it sit and just come back an hour later and see.

    BTW, if Pilas are you intention for the KL4 mod, using the stock circuit may be the way to go, as CM has discovered. This is the way I run mine, Thanks CM, and it runs great.

  18. #18

    Default Re: Feeler on modded KL4\'s

    I'm interested in one of these, Tony.

    I get confused when it comes to all these circuits and various Surefire LED lights.

    I'm kookoo for these Lux IIIs. I've got one of Don's McLux 917s so onward and upward for me. I want a 1000 or higher next. I really like the L4 body and head, but I don't want another 5 watt.

    BC

  19. #19
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    Default Re: Feeler on modded KL4\'s

    There seems to be renewed interest in modded KL4's. If any of you are interested, PM me. I don't always check this thread and may miss a post.

    I DO NOT have any hosts right now. The best I can do is mod KL4's sent to me. I usually get my L4's on B/S/T then sell the body and switches off. This made the KL4 affordable for the mod, so unless I can get an entire L4 for $110 or less, I don't buy them and there haven't been any for sale lately.

  20. #20
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    Default Re: Feeler on modded KL4\'s

    I too would like a III put into my kl4 head. Either stock electronics or a DB700. looking to get more throw with at least the same runtime or longer. I am open to suggestions, as there are plenty of highly qualified people here who know much more than i. dave

  21. #21
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    Default Re: Feeler on modded KL4\'s

    Just in case anyone was interested. I took two modded KL4's. One with the stock circuit biased at ~900mA. The other with a DB1000. Both had Q3J's in them. After having let them run for 1 hour, I went to check on them.

    The one with the stock circuit had gone out, presumeably because the protection circuit on the batt kicked in. The one with the DB1000 was still going strong. No noticeable decrease in brightness. I pulled the batt and took a voltage reading and it read 3.7v. I took a current reading from the batt and it measure ~700mA. I'm gonna guess that it was no longer regulated, but running in direct drive. It was still bright. Just some subjective observations. I'll have to do a real runtime test one of these days, but for now, I'm pulling the stock circuit out of my personal KL4 and replacing it with a DB700.

    It appears that when using Pilas, the LED, in the case of the modded KL4 anyway, fare better with the buck circuit than with the boost circuit. It seems that the Pilas have plenty of umph left to run the LED in DD mode once it drops out of regulation with the DB. I wish I knew how to crunch the numbers on this.

    CM, can you enlighten us. It seems that you get bright light for a longer time with the buck circuit than with the boost circuit.

    Is the stock circuit that inefficient or does the buck circuit put less of a strain on the batt providing for a longer truly useful runtime.

  22. #22
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    Default Re: Feeler on modded KL4\'s

    Ginseng,

    A buck should run the light with a Li-Ion, it just *may* not run it in regulation depending on where the Vf of the LED is and how hard you desire to run it. The one I modded is a boost (it's the stock circuit rebiased to 878mA) so that it is strictly limited to Li-Ions. The Vf of the LED at 878mA (which is where I set mine) is about 4.2V. A buck circuit (unless it's a synchronous buck circuit) will drop the battery voltage by about half a volt by the time the LED sees it. So take 4.2-0.5=3.7V which is probably underdriving a 3W to closer to 1.5 W. If you want to run a 1W or 3W to 700mA or above off a Li-Ion, a boost is the way to go, but that means no running the light on 2x123's. You also want to distinguish it off your other KL4 heads so that you don't inadvertently put 2x123's behind it and possibly blow the circuit. The LED will survive, the Schottky diode probably won't.


    Chop,

    I use Pilas with the boost circuit. I don't have any with the bucks yet. I do have some interesting data on my KL4-1W. I'd like to post it but it's a pita to post Excel graphs. It reveals a lot of things about the stock circuit in the KL4.

    CM


  23. #23

    Default Re: Feeler on modded KL4\'s

    CM,

    You can email me the Excel graph and I can post/host them.

    Wilkey

  24. #24
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    Default Re: Feeler on modded KL4\'s

    Wilkey,

    Incoming. Thanks.

    CM

  25. #25

    Default Re: Feeler on modded KL4\'s

    Thanks Cris,

    I'm still trying to understand your last reply [img]/ubbthreads/images/graemlins/grin.gif[/img] Don't worry, gimme a few hours.

    Wilkey

  26. #26
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    Default Re: Feeler on modded KL4\'s

    [ QUOTE ]
    Chop said:
    CM, can you enlighten us. It seems that you get bright light for a longer time with the buck circuit than with the boost circuit.


    [/ QUOTE ]

    Chop,

    The DB is probably not running the light in regulation so it should run longer. 4.2V will probably not drive a Lux at 1A. If you try to draw an amp from a Li-Ion, the voltage will sag to about 3.8V or less. At that voltage minus losses, the Lux is probably being driven at 500-600mA. At that bias, you ought to get at least two hours of light.

    Remember people's claims of the TW4 running longer on 1 cell than on two cells? Well it's because of the light drawing less current when it is out of regulation. Same thing applies here. There is a way to estimate the relative efficiencies of the two circuits and that is to plot input voltage vs input current for both converters. LED forward voltage also come into play and wreak havoc on our conclusions. Wilkey's gonna post a graph showing what I mean. If you know the circuits well, you can also estimate efficiency.

    The reason you may not see a difference in brightness is that it takes doubling (or halving) of output for you to be able to tell. If you have a lightmeter (yet another toy to add to your ever growing collection [img]/ubbthreads/images/graemlins/grin.gif[/img] ), that's the most objective way to determine whether your light output is diminishing.

    CM

  27. #27
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    Default Re: Feeler on modded KL4\'s

    CM,
    The 1A KL4 that I was messing with above has a Q3J in it. I don't know the actual Vf of this particular luxeon, but the J Vf is relatively low. Like 3.25-3.5v or something like that. If we take the voltage sag attributable to the circuit into account we only have a couple of tenths of a volt to play with and stay in regulation. The odd thing is that after running the KL4 for an hour on the Pila, I took a current reading off of the batt at the tail end and the lux was still sucking 700mA from the batt. A voltage check of the batt showed 3.7v. Is the DB still parasitic even after it falls into DD mode? If so, how much of this 700mA do you think was making it to the LED? Is it the 500-600mA as stated above? I have to say, it was still bright.

    If so, the best way to go for full brightness may be the stock circuit when using the Pilas. Where'd I hear that before? [img]/ubbthreads/images/graemlins/grin.gif[/img] Cris, you da man!!

    BTW, It was brighter when I put 2X123's in it. I'm glad to know this about the DB setup and the rechargeables. I think it's a plus especially in situations where you might have a few extra rechargeables, but no way to recharge them.

    Thanks Cris, again!

  28. #28

    Default Re: Feeler on modded KL4\'s

    Here are the graphs CM sent me. I'll leave it to him to comment. I cleaned them up a bit graphically to make them view better.

    Wilkey






  29. #29
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    Default Re: Feeler on modded KL4\'s

    Chop,

    Vf of the Q3J is measured at 350mA. It will increase as you drive the LED harder. At 1A, I measure about 4.25V which is above the open circuit voltage of Li-Ions. It's hard to say what's going on with the Downboy since I don't have one built up to test and graph [img]/ubbthreads/images/graemlins/smile.gif[/img] Since the DB gets brighter with 2x123's, that means it was running out of regulation on the Pila's. However, you were hard pressed to tell that so I think a buck will serve well in a pinch. The only reason I use the boost is that I'm lazy [img]/ubbthreads/images/graemlins/grin.gif[/img]

    CM

  30. #30

    Default Re: Feeler on modded KL4\'s

    Thanks guys! You are the best. I've decided to go for the TWAK on the stock board. I'm having a KL4 sent directly to you, Tony. CM, thanks so much for your patient guidance. [img]/ubbthreads/images/graemlins/smile.gif[/img]

    You guys are the most down to earth, accessible modders/enthusiasts I've dealt with in some time. It's refreshing to work with craftsmen who are so not primadonnas.

    Wilkey

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