# Mini-KT3: World's first ~1000-lumen Minimag



## TigerhawkT3 (May 29, 2009)

This is a Minimag modded with an MC-E and Li-Ions, driven pretty darn hard. I'm not certain that it's never been done before, but it's definitely the first one I've heard of.

Body: Traditional incan Minimag
Window: Stock plastic
Optic: Carclo 20mm Frosted Medium optic, model 10195
Emitter: MCE4WT-A2-5A0-K0-0-00001 370 min Lumens Neutral White, wired 2S2P
Epoxy: Standard 2-part AA
Heatsink: mariposaoyako's OFC solid copper heatsink, modified
Battery: 2x14500 AW protected Li-Ions in series
Tailcap: Nite-Ize clickie (if anyone knows of a better clickie, please share it)

Here's a macro of the MC-E. How, uh, exciting.






This is a closeup of the wired MC-E. That wire looping around the top connects pairs of terminals for the 2S2P configuration. I'm glad I didn't have to individually address each of the eight tiny contacts for this mod. 





Here's the back of it. Notice how I put very little solder on this side - that's because the little contacts are extremely close to the surface. I actually had to bend each one upwards with some fine needlenosed pliers before I started.





This is how the wired emitter looks as it sits on the heatsink with the wires going through the proper heatsink holes. Nothing is glued; it was basically a practice assembly so that I could plan.





Here's a closeup of the heatsink and wired MC-E, after a little modification. To put it shortly, the wired MC-E is a ship and the copper retaining ring is a bottle. This way, I could connect everything in place with a bit of slack, then slide the ring in from the side, past the wires, and screw it down. I probably could have avoided that by soldering the wires to the MC-E as the last step, but that would be more difficult and give me much less room with which to check for shorts and so on.





I then noticed that the Minimag itself presented another ship-in-a-bottle dilemma. However, that lip is much thinner than the retaining ring, so I was able to tilt the MC-E slightly, slide it in from the tail, then pull it all the way out the neck and tilt it back down. This pic shows the wired MC-E tilted and poking partly through the neck.





I clipped the long leads to the proper length, making sure to give myself space to slide in the heatsink retaining ring, then stripped the ends and wired them up. I popped the emitter off a dead sandwich module I had lying around, ground the little conductive patches off one side, and used the other side's large conductive surface as the contact for batt+. If you look closely, you'll see the ground wire screwed to the heatsink, just like mariposaoyako intended.





Here, the assembled module has been inserted up through the tail with the tilted MC-E still floating. I pulled the MC-E through the Minimag's neck and righted it.





I then put a couple AA alks (the ones that originally came with the Minimag, as a matter of fact) into the Minimag, so I could push from the bottom and screw on the retaining ring. The optic (Carclo 10195) is resting on the left. Notice that nothing has been AAed yet. If I wanted to at this point, I could have unscrewed the retaining ring, slipped the MC-E back through the Minimag's neck, and worked on it some more. I didn't end up needing to do that, though.





After that, I mixed some AA, put it under the emitter, and closed the light, using the pressure from the optic on the emitter to press it gently but firmly into the AA.





The following step was very important. I spent quite a bit of time doing it while the AA dried. "O Lord, bless this Thy... FLASHLIGHT... that with it Thou mayest... NOT... blow Thine enemies to tiny bits..." These AW cells are protected, but I still really really didn't want a short, or magic smoke, or any of that jazz.

Several hours later, I decided to go ahead and just take the plunge. I took the 14500s from my Auroralite (one measured at 4.2V, the other at 3.9V), put tiny magnets at the proper places, and screwed on the Nite-Ize tailcap.

Settings were kept locked for both of the following pics. You can look at the EXIF data if you want the details. Room lights (warm fluorescents) were on for both pics. The white balance is way off, but since that's really hard to do properly anway, I can just tell you about tints.

Nitecore D10, GDP version, on High, with a NiMH. The classic creamy white hotspot, slightly yellow-green corona, and white spill.





Mini-KT3. This emitter is slightly on the warm side, but still definitely white, IMHO. Quite pleasant.





Battery was 8.1V OC, current draw around 2A. I don't think it's 1000 "SF lumens," I don't know if it's OTF but with fresh cells, it may or may not be emitter lumens with fresh cells... but it's gotta be close to one of those.

AFAIK, this is the first MC-E Minimag, and the brightest Minimag (one might say, the "Penultimate Stealth Light"  ). I don't pretend to have conducted an exhaustive or even perfunctory search for others, but I did a couple Google searches and didn't find anything. If I'm wrong, please let me know.


----------



## saabluster (May 29, 2009)

TigerhawkT3 said:


> (one might say, the "Penultimate Stealth Light"  ).


:thinking: The next to last stealth light? Thats rather confusing. Quite scary build I must say but at least you took the proper steps to protect yourself before inserting those batteries.


----------



## TigerhawkT3 (May 29, 2009)

saabluster said:


> :thinking: The next to last stealth light? Thats rather confusing. Quite scary build I must say but at least you took the proper steps to protect yourself before inserting those batteries.


Although it's in no way the light's official name, yes, I do like to think of the Mini-KT3 as penultimate. The ultimate one is the USL (Ultimate Stealth Light), an Osram 62138 with 11xNiMH in a 2D. 

Oh, I've been very careful with shorts since the incident with the 36 high-current AA series-wired NiMH pack... followed by the incident with the 10Ah SLAs...  Those were not pretty.


----------



## clg0159 (May 29, 2009)

saabluster said:


> :thinking: The next to last stealth light? Thats rather confusing.


 
He must have had his collection of stealth lights lined up

Seriously though, that is nice! I pondered such a setup, but my wedding budget choked out my build budget.

I would love to see some outdoor beamshots when you get a chance!


----------



## saabluster (May 29, 2009)

TigerhawkT3 said:


> Although it's in no way the light's official name, yes, I do like to think of the Mini-KT3 as penultimate. The ultimate one is the USL (Ultimate Stealth Light), an Osram 62138 with 11xNiMH in a 2D.
> 
> Oh, I've been very careful with shorts since the incident with the 36 high-current AA series-wired NiMH pack... followed by the incident with the 10Ah SLAs...  Those were not pretty.


I guess I wasn't clear enough. Penultimate means next to last. It has nothing to do with ultimate. If you did indeed mean that your light was next to last than sorry I said anything.


----------



## TigerhawkT3 (May 29, 2009)

saabluster said:


> I guess I wasn't clear enough. Penultimate means next to last. It has nothing to do with ultimate. If you did indeed mean that your light was next to last than sorry I said anything.


Well, since "ultimate" can mean "the last or final thing in a series" as well as "the greatest possible," I guess I just assumed that penultimate could mean "next to the greatest possible" as well as "next to the last or final thing in a series." Darn. Well, that's learning. 

Now, if I may go off-topic for a moment, I'd like to mention a Minimag mod that I finished recently. 

Any reliable, low-resistance Minimag tail clickies? The Nite-Ize one is 0.7Ω, which is over a watt of wasted power in this light.


----------



## saabluster (May 29, 2009)

TigerhawkT3 said:


> Well, since "ultimate" can mean "the last or final thing in a series" as well as "the greatest possible," I guess I just assumed that penultimate could mean "next to the greatest possible" as well as "next to the last or final thing in a series." Darn. Well, that's learning.
> 
> Now, if I may go off-topic for a moment, I'd like to mention a Minimag mod that I finished recently.
> 
> Any reliable, low-resistance Minimag tail clickies? The Nite-Ize one is 0.7Ω, which is over a watt of wasted power in this light.


You aren't running all that power through the switch are you? Might be better to do the same the as the high power incan guys do and run the power through a FET.


----------



## TigerhawkT3 (May 29, 2009)

saabluster said:


> You aren't running all that power through the switch are you? Might be better to do the same the as the high power incan guys do and run the power through a FET.


Uh, yeah, I am indeed.  I used it with an Auroralite (very similar voltage and current) and it seemed to work fine. If it eventually melts itself closed, I can just remove it and buy a new switch.

A FET would be really neat! Unfortunately, I don't know how to use one, don't know how to shop for them or where to buy them, and don't know where or even whether it would fit into a Minimag.  Unless I find a pre-made FET tailswitch, the likelihood of such a change is very low indeed. Alternatively, a plain high-current switch or switch mod would also fit the bill, if anyone knows of one.


----------



## Mjolnir (May 29, 2009)

The way that you have it wired, how much voltage is going to each die? I am not all that familiar with how multi die LEDs are "wired," but it seems like you are running that LED at upwards of 14 watts (around 7 volts and 2 amps). How hot does the minimag get?


----------



## gswitter (May 29, 2009)

I don't have one, but Malkoff Devices apparently sourced some higher current Krolls for their new MD2. Still might not be high enough for your application. I don't see it listed on the Malkoff site, but I think I've seen a few people post that they've received them.

Wonder if a NiteEyes IQ switch can handle the power? I've tried one successfully with a 6V P60 drop-in, but I don't recall the current draw. If you don't have an IQ switch, I'll bring one to try/sacrifice to the BBQ on Saturday. :devil:


----------



## TigerhawkT3 (May 29, 2009)

Mjolnir said:


> The way that you have it wired, how much voltage is going to each die? I am not all that familiar with how multi die LEDs are "wired," but it seems like you are running that LED at upwards of 14 watts (around 7 volts and 2 amps). How hot does the minimag get?


2S2P is two parallel strings of two emitters each. If the whole array has 2A going through it, that means each string is seeing 1A (more or less - if the P7's dies are balanced, the MC-E's should be, too). Each of these strings has about 8V across it, as each string has two emitters. And yes, that is around 16W (the cells are pretty fresh, so the batt is closer to 8V). It gets warm in a few seconds, and I'm sure it would get hotter if I ran it longer than that. However, I've limited it to runs of under five seconds or so. After so much planning, money, and effort, I don't want to let out the magic smoke. 


gswitter said:


> I don't have one, but Malkoff Devices apparently sourced some higher current Krolls for their new MD2. Still might not be high enough for your application. I don't see it listed on the Malkoff site, but I think I've seen a few people post that they've received them.
> 
> Wonder if a NiteEyes IQ switch can handle the power? I've tried one successfully with a 6V P60 drop-in, but I don't recall the current draw. If you don't have an IQ switch, I'll bring one to try/sacrifice to the BBQ on Saturday. :devil:


Sweet! I'll definitely have to get one of those Krolls. I Googled a few threads, and it can apparently handle 4A, more than enough for this light. Many thanks for this! :thanks:

And no, I don't think an IQ switch would work. It's infamous for cutting output in half, even on High mode. I'm not sure I want to find out how it would behave with this kind of power. 

I'll see you at the BBQ!


----------



## TigerhawkT3 (May 30, 2009)

I topped off the battery last night, bringing voltage from 8V to 8.2V. Current went from 2A to 3A, and the Nite-Ize switch is no more. :laughing: Looks like you were right, saabluster.

I've used Gene's website contact form to ask him to notify me when those high-current Krolls are available. Hopefully it'll be soon.

I also realized that I probably could have made this mod entirely without the retaining ring. The module would be stopped from dropping out only by the MC-Es contacts, so some extra insulation over the neck would be necessary, but the light would turn on and off normally (classic Minimag head twist) with the stock tailcap. Oh well... next time.


----------



## Mjolnir (May 30, 2009)

Well a fully charged lithium ion battery is around 3.7 volts under load, so I would expect it the batteries to be around 7.4 volts at full charge, not 8.2.


----------



## TigerhawkT3 (May 31, 2009)

Mjolnir said:


> Well a fully charged lithium ion battery is around 3.7 volts under load, so I would expect it the batteries to be around 7.4 volts at full charge, not 8.2.


Yeah, sorry about that, I meant OC, like in my first post. I should've been clearer.

I'm pretty content with measuring volts OC, looking at current, and then estimating the current under load, since it'd be kind of a hassle for me to take that reading.

News from the BBQ yesterday: First, I stopped by Fry's beforehand to get a new switch. I got the RAM branded one, since I didn't see the Nite-Ize model being offered by itself. I'm happy to say that it works nicely.

The IQ switch does indeed work with it, gives all the modes, and did not break, although (as usual) it's a lot dimmer than without it, even on High. I was so surprised that it worked that I kept on turning it on and cycling through the modes again and again. :laughing: Interestingly, the MC-E glows dimly while in Off mode, and gives a brighter flash every time the red LED in the tailcap flashes. Still, I'll be sure to buy one of these tailcaps just in case I need to convert this thing into a practical flashlight for a little while. :laughing:

I was also able to use the calibrated homemade IS that was set up there to test the output of this light. With the head on, we got 639 lumens. With the head off, we got a "peak" reading of 954 lumens. 

I think that's pretty darn close to 1000, given how the cells could have been a tiny bit more charged, a lower-resistance tailcap could have been used, I could have figured out earlier to use the stock tailcap and no retaining ring, and so on.

Conclusions:
-I'm very happy with this light.
-I'm confident that it is a ~1000-lumen light.
-I'm pretty confident that it is the world's brightest (lumens, not lux, of course) Minimag.


----------



## clg0159 (May 31, 2009)

TigerhawkT3 said:


> I was also able to use the calibrated homemade IS that was set up there to test the output of this light. With the head on, we got 639 lumens. With the head off, we got a "peak" reading of 954 lumens.
> 
> -I'm pretty confident that it is the world's brightest (lumens, not lux, of course) Minimag.


 
Congratulations on that! That quite a sleeper!


----------



## Al Combs (May 31, 2009)

Awesome. I always had a thing for MiniMag sleepers. I guess because when I bought my first MiniMag 20 years ago there was nothing else like it.

I don't know if this will be of any help, have you seen this post on FET switching? The very first picture in this post shows a diagram made by member JimmyM. That would answer the, "I don't know how" part of your #8 post. I am sorry but I don't know where to get something small enough to fit. The TO-220 that petrev was using might be a little too big. I did a quick search on a few of the semi sites for a tiny package like SOT-23. All of the MOSFET's I saw were both integrated into the output of some sort of regulator and not powerful enough for your needs. The stand alone "just switches" were in the larger packages that won't fit. Maybe you could start a thread in the Incan forum just to ask.

Besides the problem of finding one, the lower internal resistance of a MOSFET might be enough to blow your MC-E. I remember you mentioning in your concept thread you might use LiFePO4's. That would solve the too much power problem. Was it just a matter of this is what you had on hand at the time? If it was me, I could imagine not wanting to wait a few more weeks.:devil:

Here's a though, replace the tailcap spring with a washer just high enough for the batteries to touch the circuit board in the heat sink when it's say half a turn from fully tight. It would still be in the range of the O-ring for whatever degree of weather protection the MiniMag provides. And you'd be back to a twisty, just from the other end. That could be a problem again as far as the lower resistance might blow the MC-E.


----------



## bigchelis (May 31, 2009)

This little mini mag was the clear and proven champion at the San Jose BBQ. It is so small and nearly 1000 out the front lumens as tested by MrGman himself. :thumbsup:

Congratulations!!!!!!!!!!!!!!!!! 

bigchelis


----------



## Al Combs (May 31, 2009)

Here's a single N-Channel MOSFET that will handle 3.2 amps and 20 volts in a SOT-23 package. Hard to believe anything that small can switch a 64 watt device. It's fully saturated at 4.5 volts. So your 2s2p config and ≈ 6.4 volts sounds like it should work.

Not being an electronics specialist, when they start talking about single, dual, hex... I have no idea what all that means. Maybe someone that does know can take a look and say if this will work or not. The specs say the gate can handle up to 12 volts. Will the 10K resistor in the JimmyM diagram be OK?:shrug: I guess you need something as both ends of the battery are hooked up to the gate when the switch is turned on.

Mouser has 8000 in stock and they cost just $0.36 each. So get a 2 ohm resistor as a dummy load for a test just in case it starts smoking.


----------



## MrGman (Jun 1, 2009)

TigerhawkT3 said:


> Yeah, sorry about that, I meant OC, like in my first post. I should've been clearer.





TigerhawkT3 said:


> I'm pretty content with measuring volts OC, looking at current, and then estimating the current under load, since it'd be kind of a hassle for me to take that reading.
> 
> News from the BBQ yesterday: First, I stopped by Fry's beforehand to get a new switch. I got the RAM branded one, since I didn't see the Nite-Ize model being offered by itself. I'm happy to say that it works nicely.
> 
> ...





Please note that this light put out those very high lumens numbers for less than 1 second!!!!!. I used the "peak" capture feature of the meter to get these. Just using the normal reading mode which takes 1 second to update it was down in the 400 lumen range and give it 3 seconds to warm up and it was down into the 300 lumen range. neither the batteries nor the LED and its Phosphors can sustain this output for anything other than a turn on pulse. 

Except for all those lights with soft start feature, I am sure I can capture extremely high numbers for a lot of other lights with the peak hold feature as well. I normally don't for obvious reasons. A light that can't even have a peak output hold for 1 full second can't really be considered to have that type of output taken seriously. Its gone before your eyes can adjust to it. So after that first second its just sucking down battery juice and fading away fast. Still Kudo's for making it without it going  at turn on.


----------



## Al Combs (Jun 1, 2009)

I found an IRF HexFET in a SOT-23 package that has even better specs. It cost 61 cents + shipping. Looking back on the JimmyM picture again, unless I missed something, an FET won't work in a tailcap switch in the MiniMag. The reason it works with the KIU socket mod is because in the front of the MagD you have access to both poles of the battery. I saw several wiring examples of a MOSFET used as a switch that show B+ going to the gate through a switch and B- going to the gate through a resistor. I guess that's using an N-channel FET?

I would love to hear from the electronics gurus about this. How for instance does the AW 3 Level Softstart work in Surefire tailcaps if it only gets wired to the minus end of the battery? Isn't this just a fancy variation of an FET switch?

Once again I seem to be getting more confused the more I learn.:thinking:


----------



## TigerhawkT3 (Jun 4, 2009)

For this particular one, the prototype, I'm probably just going to wait around for a low-resistance Kroll from Malkoff. For future ones, I would just eliminate the heatsink retaining ring and use the classic head-twist switching method.

BTW, is anyone interested in getting a light like this from me?


----------



## TigerhawkT3 (Jun 7, 2009)

On the night hike yesterday, I realized that even with its lumen output, the Mini-KT3 had very little throw with the optic I used. I rooted around for the aspherics I bought a while ago, and I was able to remove the optic and put an aspheric in front of the window, held in place by Mag's anti-roll bezel cover. There's an extra window just below the aspheric to keep it from rattling. At the focus point, it projects an image of the four dies, and the head can be defocused or removed entirely for flood. It's pretty nifty, IMHO, even though the aspheric bulges a bit beyond the bezel cover.


----------



## kramer5150 (Jun 7, 2009)

I think the most surprising thing about this DIY is that the OP is using a $6 click switch, instead of the twist-bezel..
http://www.tacticalflashlights.com/flashlights/RAM10001.html

Overall a pretty impressive little spot-use kind of mod imho:thumbsup:


----------



## Illum (Jun 7, 2009)

oh no you didn't!

2x14500s...sounds dangerous


----------



## TigerhawkT3 (Jun 11, 2009)

I found that I lose a lot of output with the aspheric setup. I'm going to try the Boom reflector out. If that doesn't work, I'm going to go back to the Carclo.

I think I have to make a new Minimag to use this aspheric with.


----------



## kramer5150 (Jun 11, 2009)

Illum said:


> oh no you didn't!
> 
> 2x14500s...sounds dangerous



I speculate the "sag" of the cells is what prevents this one from.... that and the OPs discipline not to leave it on for longer than ~20 seconds. its got a really nice color tint too, warmer color than one would expect.


----------



## TigerhawkT3 (Jun 11, 2009)

kramer5150 said:


> I speculate the "sag" of the cells is what prevents this one from.... that and the OPs discipline not to leave it on for longer than ~20 seconds. its got a really nice color tint too, warmer color than one would expect.


WRONG! It's fear, not discipline, and it's more like five seconds, not twenty. 

I played around with the Boom reflector, but I don't think it's going to happen. The bottom of the reflector actually touches the mounting surface on the sides of the MC-E without leads, and is raised barely a millimeter on the sides with leads. It also doesn't fit in the Minimag head. At best, it would need some shaving to fit into the head, as well as some careful cutout work to actually sit on the LED properly. The optic, in contrast, sits just on top of the dome, without any excess material around that. It would've been nice to get a classic reflectored beam (and focusable too), but oh well.


----------



## TigerhawkT3 (Jul 16, 2009)

I EDC this, and it still makes me smile when I light up a room.


----------



## TigerhawkT3 (May 29, 2011)

Well, after nearly two years of EDCing this light, I think it's time to retire it. I noticed last night during dinner that it was on, with very faint output. I turned it off, recharged the cells, and put them back in. When I got the contacts right, I found that it was quite dim. It was pulling less than 1A, with less output than common XR-E lights. The cells seem to be working fine, at 4.1-4.2V, powering other flashlights properly. I think the MC-E itself may have degraded, unfortunately.

It's too bad the light is crippled, but I'm glad I used it a lot, and a lot of people got to see it. There probably won't be a follow-up, since I don't think there are any places offering Minimag heatsinks anymore, AFAIK. I'm probably going to start looking for a replacement EDC (to complement my Nitecore D10 GDP) in these newfangled XM-L lights or something.


----------



## mvyrmnd (May 29, 2011)

It's nice to get a follow up. Sorry to hear of its death.


----------



## TigerhawkT3 (May 29, 2011)

mvyrmnd said:


> It's nice to get a follow up. Sorry to hear of its death.


 Eh, I'm kind of thinking of it like a workhorse that gets put out to pasture. At least it didn't fall and break a leg, or wander off and get lost, or what have you. It can't do what it used to any longer, but it's still hanging around.

It is, of course, possible that it's undamaged and that I'm just missing something. Maybe it does need new cells; I really don't know. After that accidental activation, though, I think there's a good chance that it really is time for its retirement. Even if I got it fully functional again, I think this was a hint that it's time to stop pressing my luck with it. It's been dropped, fallen out of the holster, had the cells run down, and now been left on for an undetermined amount of time (not the best thing with Li-Ions, even protected ones like I used).


----------

