# Finished: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe



## Techjunkie (Feb 6, 2012)

*update #3* The taicap resistors and improved regulator heatsinking now have the light dialed in perfectly. I can run on max current until the head is uncomfortable to hold without the regulators overheating. See updates in post #31.

*update #2* The KD V2 regulators overheat way too easily in this application (maybe it's the 380mA 7135 vs the 350mA ones) have to rework the drivers (having deja vu here. when will I ever learn?)

*update* Build complete. Beamshots in post #11.

I'm finally starting the build log for this light, but the truth is I've been collecting parts for it for months now. The finished specs will be:



Mag 4C
Glass lens
Quad Optic (edges trimmed)
Cu PES C heatsink machined flat (drilled & tapped)
4x 5000K CREE XM-L (my new favorite tint)
One individual 3.04A regulator for each LED, mode slaved (KD V2 regs with 380mA per 7135)
3 modes: very low, medium very high (my new favorite mode group thanks to these new V2 boards)
4x AccuPower Evolution NiMH LSD C cells 4500mAH (4.8V pack voltage ensures full power available through nearly the entire discharge)
12A draw at the tail, mere milliamps through the mag switch
 
I've got a new twist on my Everyman's recipe from my other builds. It occurred to me that LED positive can be connected directly to the battery instead of coming across the switch. When the regulators are off, the circuit is broken. This reduces resistance by removing the Mag switch from the LED circuit and also saves the switch from carrying 12A of current. I've tested this already with one XML, one IMR22650, and one KD V2 regulator configured for H-M-L. The only oddity that I noticed in this configuration was that the mode board's memory seemed to take a split second to kick in, causing a quick flash of high mode when turning on in, or changing to, low mode. A light that I built using the same components and mode group, but with a traditional tail switch doesn't exhibit the mode switch flash. I'm not concerned at the moment.

A quick mock-up using the old diagram as a starting point (in actuality, the new V2 regulators with 380mA per 7135 will be used:







Some pics of the mechanical parts of the build so far...


5000K emitters from DigiKey SMD soldered to 16.5mm boards from KD (top)
PES-C Cu heatsink machined flat, drilled and tapped (left)
DX Quad optic with edge trimmed to recess inside Mag C head (right)






Underside of heatsink shows color coding corresponding to dots on MCPCBs. This little trick allows me to align the LEDs in the same orientation as when measurements for holes were taken.






MCPCBs fully mounted with AS5 and #3 screws. What you don't see here is that all 8 screws had to be trimmed in length and deburred and all 8 slots in the sides of the MCPCBs had to be made wider with a 3/32" bit. (What a pain.)






Closeup of the optic positioned over the LEDs. The holes that the four pegs stand in had to be drilled to 2mm depth to position the optic the same height over the MCPCBs to simulate the wider part of the pegs sitting on the MCPCBs. This puts the optic at the correct/optimal focal distance from the LED surface.






A preview of what it will look like fully assembled. (Nothing's wired up yet.)







I decided to weigh it with everything but the drivers installed. This sucker's heavy - almost 2 lbs.!





Build completed. See posts 9-11.


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## simplec6 (Feb 6, 2012)

*Re: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

Sweet build man.


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## LilKevin715 (Feb 6, 2012)

*Re: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

Lookin good so far:thumbsup:. Is the primary heat path via the head, then to the body tube with AS5 on the threads? Or will the bottom part of the heatsink make contact with the body tube directly?


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## Hill (Feb 7, 2012)

*Re: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

Hi TJ,

Nice looking project. I really like the idea of a multi-XML powered by NiMh C cells. The host is quite long, but given it is a C-body, it's not too fat in the hands. Nice machining work on the sink. In all my builds, this is the part that usually takes the longest, and I understand how much of a pain it is without fance tools (i.e. lathe, etc).

Looking forward to the final product!


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## beekeeper5 (Feb 7, 2012)

*Re: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

Will this be a throw or spot light?


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## Techjunkie (Feb 7, 2012)

*Re: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

@LilKevin715: The way the HS is shaped, all of its underside, except the cavity in the center, makes contact with the neck and with the head. Besides that cavity, the only surface not making thermal contact with something is the spaces on the surface between the MCPCBs.

@Hill & Simplec6, Thanks


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## fortean101 (Feb 8, 2012)

Where did the quad optic come from? I have a quad XML mag as well but the head is not stock and I want to swap if for a standard one. Lovely build by the way!


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## Techjunkie (Feb 8, 2012)

*Re: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*



beekeeper5 said:


> Will this be a throw or spot light?


 4 XML in a 2" head will be unavoidably floody, but the optics will make it as much of a spot as possible with the given dimensions. (Not counting 4x20mm aspherics lenses, one suspended over each LED)



fortean101 said:


> Where did the quad optic come from? I have a quad XML mag as well but the head is not stock and I want to swap if for a standard one. Lovely build by the way!


 DealExtreme.com. Thanks.


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## Techjunkie (Feb 8, 2012)

*Re: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

Making progress...

Emitters wired up:





Regulators prepared:





It's hard to see in the pic above, but there's a drop of epoxy holding the mode signal wire in place on each board, and another drop covering the ground ring nearest to the LED- connection, to insulate that part of the ring and avoid an accidental short to ground while soldering the LED- wire in place.



Switch mods. Pass through for LED+, anti-bounce mod.


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## Techjunkie (Feb 9, 2012)

*Re: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

Construction continues...






Looking at the pics of the wires hanging from beneath the heatsink, I'm reminded of a giant jelly fish. I think I might call this one the Man O' War.

















And now for the moment of truth... tailcap mesurements

High:





Medium:





Low (like map-light low):


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## Techjunkie (Feb 9, 2012)

*Re: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

And now, without further ado, the requisite beamshots. All shots taken at 1/10 sec. F3.5 ISO 200 WB=5200K (daylight).

The candidates for comparison. From left to right:
1) This Mag 4C with 4x 5000K XML in quad optic, driven @ 3A each
2) A Mag 3D with 5x MCE 4A in SMO pentaflector, driven to 2.8A each
3) A Mag 2D with 3x SST50 4500K in SMO triflector, driven to 4.2A each










Control, lights on:





Control, lights off:





This light (4x XML quad optic)





5x MCE pentaflector





3x SST50 SMO triflector


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## Techjunkie (Feb 9, 2012)

*Re: Built+Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

Next project: Quad in a 2C, powered by 2x AW IMR26500, wired as two standalone strings of 2-in-series, using one KD V2 driver for each serial string of 2S. Board with modes powered from between LED 1 & 2 in string A. Board that regulates string B will be mode slaved from the first board. Not sure if I'll use another quad optic or 4 20mmx20mm SMO reflectors for that build.


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## FRITZHID (Feb 9, 2012)

*Re: Built+Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

that SST is so bright in the pic it almost hurt my eyes!!! nice work!


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## Techjunkie (Feb 9, 2012)

*Re: Built+Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*



FRITZHID said:


> that SST is so bright in the pic it almost hurt my eyes!!! nice work!



Thanks for the compliment, Fritz. Look again though - this 4X XML is clearly way brighter than the 3x SST50 (XML left, SST right):


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## LilKevin715 (Feb 9, 2012)

*Re: Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

As always nice work Techjunkie:thumbsup:. What is the tint of the XM-L emitters? I am guessing somewhere around the 3X range like 3C or 3D. I like the heatsinks fior the drivers, should be able to dissapate the heat. Also, how long are you able to hold the light before its too hot?


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## Techjunkie (Feb 9, 2012)

*Re: Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

I discovered that within what seems like less than a minute of running this light on high, brightness would wane noticeably, to the point where high looked like mid and low won't even light. This feels like a symptom of the regulators overheating. A tailcap measurement with the light in this condition showed that on high, current draw had dropped to less than four amps. The head never even got very warm. I immediately took one cell out and measured draw on high with three cells and current draw nearly doubled, going up to around 8 amps. If taking one cell out improves output, then the dimming clearly isn't from the batteries sagging.

My next experiment was to let the regulators cool, then run the light for a prolonged time on medium (3-4A). I let it run that way for several minutes, until the head got hot and then tried high mode immediately while it was still hot. I measured 12A at the tailcap for a while, then within about a minute, brightness began to wane, the same as it had when run as long on high from a cold start. Once again, after the regulators are overheated this way, low mode produces no output.

I've concluded that the 380mA AMC7135 chips on these regulators don't handle their max output of 380mA each very well at all, at least not compared to their conventional 350mA siblings. I can't even blame a high input voltage for making them work too hard to burn off excess, considering that nominal pack voltage is only 4.8V.

With no space to provide the regulators with better heatsinking than I already have in here, I'm left with few options:


Do nothing and refer to this as one of those lights where high is actually a "nuke" mode meant to be used sparingly, and medium is the practical "high" mode. While this "solution" appeals to my laziness and protects from me damaging what I've already created, the perfectionist in me will lose sleep over it.
Experiment with adding some resistance in the tailcap, to offset the amount of resistance (and heat) required of the regulators to hit the target current. This might work because voltage sent to the regulator is not impacted by what mode the string is in the way it would be if it were in series with the LEDs like in the poor man's method. The challenge will be finding a resistor that's capable of 12A, the right Ohm value, and fits inside the Mag C tailcap.
Move the light engine over to a Mag 3C and recycle the fourth cell in another project. Running the light engine unmodified on 3 cells instead of four means that full blast would be 8-9A instead of 12A, but I'd be able to run on high constantly instead of in short bursts.
Replace all four AccuEvo cells with another brand of NiMH C cell that sags more under 12A load. (This is sort of a twist on #2, where the added resistance comes from the batteries.) The challenge here is identifying the right cell for the job.
Replace the four KD V2 regulators used here with four of the original (KD V1, download, shiningbeam) 8x7135 multimode regulators and hope I'm right about them being needing less heatsinking.
Pot the regulators I've used here in PC Fahrenheit thermal putty epoxy and hope that helps. I've been lucky with unsinked regulators not overheating before, and think that stuff may have been the secret to my success.
2 is easy and inexpensive to attempt. 3 is slightly risky and not too expensive. 4 could get very expensive, as I tend to need to build lights for all my leftover batteries and who knows how many I'd try before I succeed or give up. 5 and 6 present the most risk of me damaging the other parts beyond repair.


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## Techjunkie (Feb 9, 2012)

*Re: Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*



LilKevin715 said:


> As always nice work Techjunkie:thumbsup:. What is the tint of the XM-L emitters? I am guessing somewhere around the 3X range like 3C or 3D. I like the heatsinks fior the drivers, should be able to dissapate the heat. Also, how long are you able to hold the light before its too hot?



DigiKey lists them as 5000K. The mfg p/n ends in E3. Not sure beyond that.

I liked the way my driver heatsink looked too, but it appears to have been insufficient (see previous post). The light gets nice and warm, but never too hot to hold (I wish it would) - the thermal regulation issue I'm having with the regulators doesn't allow 12A mode to be run long enough for the LEDs to make the light get uncomfortably hot.


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## Techjunkie (Feb 9, 2012)

*Re: Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

I just read the specs of these new V2 regulators:

Voltage support: 2.5V-4.5V
Battery types: 1xLi-ion or 3xNiMH/alkaline

Doh! When did that come down from 6V, 4x NiMH?

:hairpull:

I can still try #2 by adding resistance just to the input voltage on the driver (If I had any idea how few mA the driver itself draws or how much to drop it), but I have a feeling the only real solution here will be #5 - replace 'em all.


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## LilKevin715 (Feb 9, 2012)

*Re: Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

The Vin range of the AMC7135 linear regulators is still the same irreguardless of 350 or 380ma versions of the chips (see spec sheet). From another older thread (scroll down to post #56) it appears that the chips are overheating big time. Those Accupower cells are being discharged at approx 2.6C, so they should be sagging pretty decently (would need to measure while under load). I'd imagine/assume Vin @ 12A would be in the neighborhood of around 4v. Assuming a LED Vf of ~3.3v (cree data sheet) the 7135 chips would have to burn off somewhere around 6-8 watts of heat.

My view on your options:
1) I wouldn't accept nothing less than a full 12A.
2) Kind of half... you know what I mean. It could be done though. I = V/R so a resistor in the neighborhood of .025 to .040 ohms, depending on how much the accupower cells sag under load (need to measure).
3) See #1
4) Ehhh, I'd stick with quality cells. A slight twist: go for a 3D mag with the 10A Accupower cells?
5) Won't make a difference IMO.
6) The C sized tube wont allow much room for heatsinking. I've potted my drivers directly to the main heatsink (although nowhere near as much heat as yours) in my builds (see SST-50 link in my sig).


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## Techjunkie (Feb 9, 2012)

*Re: Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

I've just exhausted most of my options...

I tried different cells of different resting voltages, then I played with different resistor values and happened upon one that made the regulators drive the light to 9.8A. After a very short while, it dimmed again. I unassembled quickly and promptly burned my hand on the driver heatsink. I've never felt a regulator that hot before, even the one that was overheating in my triple SST50 light that I fixed successfully with a similar heatsink.

I'm going for option #5... just not tonight.


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## Techjunkie (Feb 10, 2012)

*Re: Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

I did some rough estimate math and calculated that if the cells are dropping to 1.05 Vout under load (guessing at this figure based on what Eneloop AAs and Titanium PowerMax 1800 AAs drop to under 10A load ), that's 4.2V. Each emitter needs only ~3.3V to reach the target max current. That means to maintain max output, the regulators need to drop .9V @ 12A, and shed 10.8Watts of heat. I realize now that's asking a bit too much considering the heatsinking available to them in this space.

I've just ordered some 5W 0.15 ohm cement resistors. Two placed in parallel in the tailcap will equal one 10W 0.075 ohm resistor. Using the math above, that should drop the voltage on the pack 0.9V @ 12A and land the target voltage right where it needs to be, leaving the regulators with little to no work to do.

12A = .9V/0.075ohm
0.075ohm = .9V/12A

I'll have to heatsink the resistors in the tailcap as best I can, considering that they'll be run slightly over spec when the batteries are fully charged and the light is on high.

Before arriving at this (latest) conclusion, I had already desoldered the regulators, from when I was planning to replace them with the older versions. While I'm waiting for the resistors to arrive, I'll see if I can solder all four into a short section of copper tube, which should improve their heatsinking somewhat.

Wish me luck.

*EDIT* I think I can fit 3 x 0.22 ohm 5W resistors in parallel in the tailcap. At 12A current, they'll collectively drop voltage 0.88v, leaving the regulators very little work to do. Each resistor will run at 3.5W, which will be in spec for them. Each regulator will have to burn off 0.48W, or 1.44W collectively, which is waaaay cooler than the 10.8W they'd have to burn without the resistors.


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## FRITZHID (Feb 10, 2012)

*Re: Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

IDK if its my screen or what but the SST may be smaller, but it looks brighter... maybe it's just the color temp?


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## Techjunkie (Feb 10, 2012)

*Re: Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*



FRITZHID said:


> IDK if its my screen or what but the SST may be smaller, but it looks brighter... maybe it's just the color temp?



I'll grant that the SST has brighter spill, but that's because the XML has almost all that spill concentrated into the giant, brighter hotspot. The ceiling bounce test says its no contest. I was shocked at how much brighter it made any room in my house compared to the fixed lighting.

On to the updates...

As I mentioned, I'm re-doing the same drivers while I wait for the resistors for the tailcap to arrive. Side note - It occurs to me that if the XML weren't so low Vf, and/or if I'd not bypassed the switch, and/or I'd used cells with more internal resistance, I probably wouldn't even need the resistors to bring the pack halfway down between 4 cells and 3 cells.

Rather than just reassemble them as they were before, Here's what I've come up with in an attempt to improve heatsinking...

Run 20awg stranded copper through the three sets of large via holes at the outer ring, and solder to both sides of every board, connecting all the boards thermally. Also solder the foundation of every AMC7135 chip to the outer ring and those wires stringing the boards together, using liberal amounts of solder:






Next, cut a piece of copper pipe, customizing diameter to fit inside heatsink base. Press new driver stack and wires in place, applying liberal amounts of HS paste between the inside of the tube and the new thermal bridges created with all that wire and solder.





Fit into place, making sure the switch will line up with the switch hole when everything is fully tightened.






I'm very happy to report that everything survived this operation. I've also noted that on high, my amp meter shows 11.6A in the forward direction, and -12.9A when wired in reverse. I see now that it's accuracy above 10A is shaky, unless I take the average of those absolute values, which is just slightly above 12A.

I'm less happy to report that installing four fully charged cells has confirmed that all this new driver heatsinking has alone not solved the problem. Here's hoping that the resistors do, or I think I'll just end up swapping the 4C tube for a 3C tube and call it a day.


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## LilKevin715 (Feb 11, 2012)

*Re: Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

The AMC7135 linear regulators are relatively cheap and flexible (somewhat), but they do have their limitations as you have found out. Have you tried the light outside yet? I am curious how much throw those optics provide.


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## Techjunkie (Feb 13, 2012)

*Re: Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*



LilKevin715 said:


> The AMC7135 linear regulators are relatively cheap and flexible (somewhat), but they do have their limitations as you have found out. Have you tried the light outside yet? I am curious how much throw those optics provide.



I have, but I haven't taken beamshots outdoors yet. Throw is on par with my triple SST-50, but with an entirely different beam profile. The hotspot of this light is a huge rounded square that reaches as far, perhaps slightly farther, than the smaller hotspot of the SST light. These optics gather a lot of the light that would be spill in a reflector, and add it to the hotspot.


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## CKOD (Feb 13, 2012)

*Re: Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*



FRITZHID said:


> IDK if its my screen or what but the SST may be smaller, but it looks brighter... maybe it's just the color temp?


The image is saturated/washed out in the center. its impossible to compare the brigtness unless he stopped down the exposure or added filters


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## netprince (Feb 13, 2012)

I like this build a lot. That optic is really interesting. A shame about the overheating drivers. Have you considered a different driver all together? My first instinct would have been one of the taskled drivers, directly attached to the bottom of the copper heatsink.

BTW, sorry if I missed it, but what is the sku on that optic? I might like to try it sometime... 

Thanks!


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## Techjunkie (Feb 14, 2012)

*Re: Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*



CKOD said:


> The image is saturated/washed out in the center. its impossible to compare the brigtness unless he stopped down the exposure or added filters


 I agree. I've charged the cells in all the lights and will take some better beamshots for comparison soon, maybe tonight.



netprince said:


> I like this build a lot. That optic is really interesting. A shame about the overheating drivers. Have you considered a different driver all together? My first instinct would have been one of the taskled drivers, directly attached to the bottom of the copper heatsink.
> 
> BTW, sorry if I missed it, but what is the sku on that optic? I might like to try it sometime...
> 
> Thanks!


 Thanks, netprince. I don't think I could fit 4 Task LED drivers into one light. (Keep in mind that pack voltage is only 4.8V, and I want each LED regulated individually at 3A, not 2x2 in parallel at 6A or 4 in parallel at 12A. That's why four are needed.) Also, I'm not sure how to do the mode-slaving on them in the same way as I'm doing on these, and cost is a concern too. DX sku for the optic is 01915.


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## Techjunkie (Feb 14, 2012)

*Re: Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

New stopped down beamshots with batteries fully charged on all lights. Current draw shown in photo captions confirmed with talcap measurements immediately following the shoot.


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## LilKevin715 (Feb 15, 2012)

*Re: Beamshots: Quad XML Mag 4C (Optics NiMH 3-mode) new everyman's recipe*

Nice beamshots. Those optics really do provide a good amount of throw. Not to mention they are more efficient (~90%) compared to regular reflectors (~75-80%).


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## Techjunkie (Feb 27, 2012)

The various 5W resistors I ordered came in the mail today. On the 2nd try, I found the right combination, 3*0.15 ohm resistors in parallel in the tailcap. Ironic that this time I would be modding a tailspring to ADD resistance, not remove it. 

Here are the three resistors fitted into the cap with the edges of two beveled so they'll fit, and the ground wire in place, and a pic of the spring taped up with kapton tape to avoid it contacting the tailcap directly, thus ensuring the current goes through the resistors, not the spring.:





Here's the tailspring fully assembled:





Here's a tail measurement from cold, without the resistive tailcap in place:





Finally, here's a tail measurement through the resistive tailcap immediately after a long run on high to the point where the head was burning my hand. I held the leads to the DMM in place long enough to ensure there was no thermal rebound and that the current shown was sustainable:





Success!


Note to self: just changed driver modes from HML to LMH, hoping to eliminate flash when power off in low mode. It didn't help, but at least the mode selector was easy to reach and the mode order matches other lights now.


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## charlestt (Apr 27, 2012)

Hi there i'm in the middle of building a similar light as your self but with 3xml U2 leds and three drivers and i'm having the same problems with the drivers getting very hot on full with 4 nimh c cells, i've tried it with 3 but i only get around 4amps that shoots up to around 10amps on four.

I want to try your method with the resistors but i don't have a clue how to work out the values and on top of that the only electrical shop i have access to don't sell exactly the same as what you've used. Would you be able to look at what they have and suggest to me the ones to go for?

Here's a link to the company in question. http://www.maplin.co.uk/search?criteria=resistor

I'm using a 3d Mag if that makes any difference..

Cheers

Charles


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## Techjunkie (Apr 28, 2012)

charlestt said:


> Hi there i'm in the middle of building a similar light as your self but with 3xml U2 leds and three drivers and i'm having the same problems with the drivers getting very hot on full with 4 nimh c cells, i've tried it with 3 but i only get around 4amps that shoots up to around 10amps on four.
> 
> I want to try your method with the resistors but i don't have a clue how to work out the values and on top of that the only electrical shop i have access to don't sell exactly the same as what you've used. Would you be able to look at what they have and suggest to me the ones to go for?
> 
> ...



Charles,

The web store that you linked to doesn't appear to have any high power resistors of low enough R value. The ones I used came from China via eBay. Try searching eBay for "Ceramic Cement Power Resistor 5W 0.15 ohm". You can get a bag of 10 for ~$3 USD. With grinding of two edges on two of them, I was able to fit three inside a Mag C tailcap. Best of luck with your build.


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## charlestt (Apr 28, 2012)

Techjunkie said:


> Charles,
> 
> The web store that you linked to doesn't appear to have any high power resistors of low enough R value. The ones I used came from China via eBay. Try searching eBay for "Ceramic Cement Power Resistor 5W 0.15 ohm". You can get a bag of 10 for ~$3 USD. With grinding of two edges on two of them, I was able to fit three inside a Mag C tailcap. Best of luck with your build.



Excellent thanks for your help i'll take a look..


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## charlestt (Apr 28, 2012)

all i can find is these but they look deceptively big ... What do you think ?

http://www.ebay.co.uk/itm/10pcs-5-W...upplies_ET&hash=item20c4b99d88#ht_2084wt_1351


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## Techjunkie (Apr 28, 2012)

Those are kinda long. I was thinking more like these.


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## charlestt (Apr 29, 2012)

Techjunkie said:


> Those are kinda long. I was thinking more like these.



Now they look more like it i'll get a set of them ordered up. 

Cheers for that


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## charlestt (Apr 29, 2012)

charlestt said:


> Now they look more like it i'll get a set of them ordered up.
> 
> Cheers for that



I know what i was going to ask you, what gauge wire are you using between the primary driver and the switch ? I'm using 20 awg but it too is getting pretty hot when on full power.


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## Techjunkie (May 1, 2012)

charlestt said:


> I know what i was going to ask you, what gauge wire are you using between the primary driver and the switch ? I'm using 20 awg but it too is getting pretty hot when on full power.


If yours is wired like mine, where the primary driver's mcu is on a parallel circuit to the LEDs, then the wire from the switch to that driver carries only a few mA. For that one, I think I'm actually using 22 awg, which is overkill. For the LEDs, each LED lead is 22 awg and the main pos wire and ground wire are 20 awg (and as short as possible).


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## charlestt (May 2, 2012)

Techjunkie said:


> If yours is wired like mine, where the primary driver's mcu is on a parallel circuit to the LEDs, then the wire from the switch to that driver carries only a few mA. For that one, I think I'm actually using 22 awg, which is overkill. For the LEDs, each LED lead is 22 awg and the main pos wire and ground wire are 20 awg (and as short as possible).



Yeah i've wired mine they same way as yours, i have 22awg going to the leds and switch and 18awg going to the battery so i guess i'm using the right stuff.
Unfortunately whilst using the flashlight the cheapo glass that i got from DX cracked so now have to wait for some decent stuff to come from the US :-/


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## Henningap (Sep 15, 2012)

Hi techjunkie,

i have seen this thread with your KD-V2 slave-mode technique few days ago and i find it quite interesting. I used this driver for a small single-xml once now and i like it. I am dreaming of building a small 7-XML-diving lamp as there is a really nice 7XML-board here in Germany. I would mill the LED-base like this:







7xml-board:






Due  to this and the fact that i will use 7 18650er from panasonic all wired  in parallel,  i dont think that i will get heat problems as you  described. Also my lamp  will be watercooled as it is a diving-lamp. I  would prefer a very simple construction, using a reed-contact to switch  the lamp on and off. This will be easy possible if i can connect the LED  positives directly to the battery as you described. 

my  question: is there more information available somewhere about your  modification to the slave mode? Or could you maybe post some more  pictures with higher resolution? How did you remove the needless parts from the board? Will there be problems when using 7 Leds?

THX a lot and regards from germany,

Henning


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## Henningap (Sep 15, 2012)

uups, i have to upload the pics, will do it later...

but i have another question regarding the driver:

its written in the instructions that below 2.8V the output power will be reduced to 35% wich should be around 1000 mah... but if i have a look inside the XML-specs, with only 2.8V it will draw around 400mah, so this is already less than 15%...
until now i havent used my first light to this point, but it will happen..what will then happen to my batteries? There will be no automatic shutdown? So if i dont realise the flashing once per minute-point, my batterie will die? (i am using unprotected 18650s)

THX again,
Henning


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