What did you mod today?

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DB Custom
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Oh, it’s aluminum shavings. I have too big a pile of those myself to not recognize them… even under the odd color liquid.

Cereal_killer
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Did me a pintrest project with my son today. Accent lighting for his room.

Edit it didn’t work, here’s a link (Idk if you have to be logged in or just open it in a new tab or what, never tried to do a video on imgur before)
https://i.imgur.com/ZhGemH2.gifv

Not sure of the imgur video is gonna embed so here’s a photo jic…

 RIP  SPC Joey Riley, KIA 11/24/14. Now I am become death, the destroyer of worlds.

hank
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“pencil mod” on the suspect capacitors on two Astrolux A01s — both now behave properly, starting on low, eliminating the next mode sometimes flakiness.

pinkpanda3310
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Super cool project CK Thumbs Up

contactcr
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Finally got my Skilhunt H03 modded. Used a LH351D and Lexel’s newest 21mm driver, flashed Anduril and bypassed that weird tail (mostly). One thing I think people don’t mention for this mod is to make sure the optic presses against the PCB firmly if you switch to a 3535 LED. I sanded down an XP butterfly spacer flat and thin and now it presses against that and holds everything with good pressure.

I also had a bad re-flow the first try thanks to the damn BLF A6 star I tried to re-use. Gotta love seeing that blue light.

MRsDNF
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My man cave needs one as well Ck. Thumbs Up

 

djozz quotes, "it came with chinese lettering that is chinese to me".

                      "My man mousehole needs one too"

old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".

Old-Lumens. Highly admired and cherished member of Budget Light Forum. 11.5.2011 - 20.12.16. RIP.

 

djozz
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My man mousehole needs one too Thumbs Up

hcanning
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Built my second S2+ triple yesterday. Headline specs:

Desert Tan S2+ Host
Triple Luxeon V 4000K on Led4Power MCPCB with MOSFET and NTC
LED4Power B4 driver
Carclo 10507 TIR optic
Kiriba-ru copper spacer
Both springs bypassed with 20AWG silicone wire
LG HG2 battery

My Nichia 219C triple (in the copper host in the photo) is the first torch I built from scratch, i.e. with a host and collecting all the parts together. I love it, and it’s a ridiculous little hot rod. But I felt I could go even further, so after some browsing of led4power.com’s site and these forums I saw that the Luxeon V seems like a very efficient and high-power emitter. I’m a huge fan of the S2+ so I decided my next build would be a Luxeon V triple.

The results are quite amazing. It is both brighter and throwier than my 219C triple, as you can see in the photos (same camera settings for the outdoor comparison shots, including the hilariously grainy high ISO setting that I didn’t notice on Lightroom Mobile!). I measured 19A with my clamp meter which is roughly the same as my 219C triple, but according to the tests posted here, a Luxeon V at 6 amps is 2000 lumens! I’m not sure if that really equates to 6K of real-life light output with three of them, but it is very impressive nonetheless.

I used the L4P B4 driver and their triple Luxeon V MCPCB with external MOSFET and temp sensor. This means 5 wires to the MCPCB rather than just 2 which made for some fiddly soldering, but it allows for much quicker, more granular temperature control, and more efficient heat dissipation thanks to the external FET. It’s quite a sophisticated little build and it works really well. You can set the temperature stepdown threshold wherever you please with the L4P driver, so I increased it a bit since the stock 65C was quite tame Smile

All in all, I’m extremely impressed with this build and the quality of L4P’s hardware. But.. I’m wondering if I can go even better and brighter with the S2+ host…. What say you all?

djozz
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I’m jealous of your soldering skills hcanning, those joints look immaculate! Shocked

hcanning
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djozz wrote:
I’m jealous of your soldering skills hcanning, those joints look immaculate! Shocked

I’m not gonna lie, they came pre-soldered from L4P, which was a nice surprise as I wasn’t expecting them to, nor did I pay for this service. But soldering the 5 wires onto the driver was very fiddly and I’m quite pleased with the results of that (forgot to take photos so you’ll have to take my word for it)! My cheapy Amazon iron has done me well over the years and I’ve never had any trouble soldering onto MCPCBs or anything really.

djozz
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Well done L4P then Smile
And a very nice mod hcanning, this may be the hottest S2+ one can build these days.

hcanning
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djozz wrote:
Well done L4P then Smile And a very nice mod hcanning, this may be the hottest S2+ one can build these days.

Thanks! I’d love to know if there’s any way of going even hotter for my next build Cool

KawiBoy1428
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hcanning wrote:
djozz wrote:
Well done L4P then Smile And a very nice mod hcanning, this may be the hottest S2+ one can build these days.

Thanks! I’d love to know if there’s any way of going even hotter for my next build Cool


Jam 4 of them in there… Big Smile

KB1428 “Live Life WOT

hcanning
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KawiBoy1428 wrote:
hcanning wrote:
djozz wrote:
Well done L4P then Smile And a very nice mod hcanning, this may be the hottest S2+ one can build these days.

Thanks! I’d love to know if there’s any way of going even hotter for my next build Cool


Jam 4 of them in there… Big Smile

!{width:50%}https://i.postimg.cc/Z5ZbCFzV/PART-1529615721077.jpg!

Shocked

Details?!

djozz
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The inside is well-illuminated Silly

DB Custom
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I’m afraid I don’t understand the external FET reasoning. The FET doesn’t typically produce heat, but the emitters on a copper star sure do. Why move the FET from the tame pcb of the driver to the hot MCPCB of 3 emitters? That seems counterintuitive to me.

So much to learn, so little time…

Tom E
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+1 with Dale, though I've been too embarrassed to ask... frown

L4P's CC drivers do result in the FET's getting hot though, just seems odd to put it on the known hot MCPCB. Obviously though it must work somehow because I'm sure L4P tests all this stuff out.

DB Custom
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Also confused that 150ºF is being called tame, if that doesn’t burn blisters on your hand then nothing is going to. If the light isn’t too hot to hold at that setting then the thermal path from the emitters is compromised.

To elaborate, I truly do know what 150º is all about, my driveway gets that hot in the summer here. It WILL burn you!

Mercury thermometer showing an actual 120ºF air temperature on my front porch…

So yeah, I’m confused as to why one would want more heat in a small light.

djozz
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The FET’s in L4P’s driver run very hot, mind that in a 8×7135 driver the burnt off heat is shared by 8 chips, a comparable amount of heat is shed by 1 FET in L4P’s drivers, and more with the modern low voltage leds and triples. So it does not really matter if the MCPCB is already say 60 degC, the heat path away from the MCPCB is so much better than from the middle of a FRP board (unlike 7135 chips, these type of FET’s do not have the thermal pad connected to ground but to led-minus!) that the higher temperature of the MCPCB is more than compensated by its better heat path.

hcanning
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DB Custom wrote:
Also confused that 150ºF is being called tame, if that doesn’t burn blisters on your hand then nothing is going to. If the light isn’t too hot to hold at that setting then the thermal path from the emitters is compromised.

To elaborate, I truly do know what 150º is all about, my driveway gets that hot in the summer here. It WILL burn you!

Mercury thermometer showing an actual 120ºF air temperature on my front porch…

So yeah, I’m confused as to why one would want more heat in a small light.

Because as soon as the MCPCB hits 65c it gets throttled. So the runtime at max is lower than I know it can handle.

DB Custom
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Oh, I fully understand all that, but with my E07 that makes 9300+ lumens set at a mere 50ºC the light gets too hot to touch in 20 seconds. Throttling it down AFTER it gets too hot to hold leaves it too hot to hold for a while… the heat dosen’t just disappear because the light stepped down. 25A in this one definitely makes for some heat, and this is a larger light with VERY ample cooling fins… the little tube lights have no such advantage.

DB Custom
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djozz, the FET is a direct drive switch of course, as such, it’s not shedding any heat but merely passing the current through. I’ve held the driver’s between my fingers at full power and they don’t burn me, the MCPCB is another story altogether, especially a triple! Granted, I’m talking a standard FET driver and not Neven’s. I have more than a few of his as well and never noticed the driver getting hot, I don’t use the external MOSFET set-up.

Of course 8×7135 regulation chips shed heat, they’re regulating what would be 6-8A of current into 3A, that difference has to go somewhere…

hcanning
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DB Custom wrote:
Oh, I fully understand all that, but with my E07 that makes 9300+ lumens set at a mere 50ºC the light gets too hot to touch in 20 seconds. Throttling it down AFTER it gets too hot to hold leaves it too hot to hold for a while… the heat dosen’t just disappear because the light stepped down. 25A in this one definitely makes for some heat, and this is a larger light with VERY ample cooling fins… the little tube lights have no such advantage.

I do understand what you’re saying. Maybe I’ll try it again at the default setting. It was definitely hot, but not as hot as I am used to from my Nichia 219C triple! I could grab it without losing layers of skin, anyway.

djozz
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DB Custom wrote:
djozz, the FET is a direct drive switch of course, as such, it’s not shedding any heat but merely passing the current through. I’ve held the driver’s between my fingers at full power and they don’t burn me, the MCPCB is another story altogether, especially a triple! Granted, I’m talking a standard FET driver and not Neven’s. I have more than a few of his as well and never noticed the driver getting hot, I don’t use the external MOSFET set-up.

Of course 8×7135 regulation chips shed heat, they’re regulating what would be 6-8A of current into 3A, that difference has to go somewhere…


The question was about Led4Power’s drivers, they use different type of FET’s in a different way, not unlike 7135 chips, in which they do not just switch on and off, but actually regulate current while burning excess power off. At max unregulated current they are not hot at all, they just let everything through like a switch does, but at half regulated current is when they get hottest.
DB Custom
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Ah, ok, that makes sense then. Didn’t realize the FET was performing in that way. Thank you for that layman’s explanation. (digesting it with a good Ethiopian coffee. Big Smile )

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Installed Nichia NV4W144AM under 45 degree TIR and H1-A in Thorfire VG-15S host.

Album with all pictures

Tricky points:

TIR is shorter than stock reflector:

So I built copper spacer using 16mm MCPCB and 2 pieces of copper foil. It should be thicker but it was compensated by extra oring between bezel and glass:

White small round thing was glued with the switch. Tailcap parts:

Mine H1-A looks different than kaidomain’s product picture. Mine:

Kaidomain:

Capton tape was added to isolate positive resistor (marked 01c?) from negative. Without isolation max current was only around 2A@4V. With isolation – over 5A@4V.

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DB Custom wrote:
I'm afraid I don't understand the external FET reasoning. The FET doesn't typically produce heat, but the emitters on a copper star sure do. Why move the FET from the tame pcb of the driver to the hot MCPCB of 3 emitters? That seems counterintuitive to me. So much to learn, so little time...

 

Linear CC drivers work by burning extra voltage into heat. This happens in MOSFET, which basically works as smart variable high power resistor. So, MOSFET is NOT in fully conductive state all the time like on DD drivers.

Math for power dissipated in FET is simple: Pfet=(Vbatt-Vled)*Iled

Djozz' statement that "FET in linear CC drivers runs hot" is not accurate in general, how hot will FET be depends on three things:

1.Amount of power disspated in FET (equation above),

2.Thermal resistance Rth (C/W) between FET case and flashlight body - this constant tells us how many C degrees will FET get hotter for each Watt of power dissipated in FET(the lower the better)

3.Flashlight temperature.

 

Math is again relatively simple for steady state conditions: Tfet= Tflashlight + Rth*Pfet

Why move FET to LED pcb?

Answer is Rth.

MOSFET on FR4 PCB has relatively poor value of Rth, I measured about 20C/W for 17mm LD-A4 driver without any thermal "improvements" like adding silicone fillers, so just driver in pill.

This means for each 1Watt of heat in FET, FET would get hotter by 20C. If you take worst case scenario where flashlight is already hot at 60C, to reach 100C FET temperature you need just 2Watts of heat Tfet=60C + 20C/W*2=100C.

That means max. allowed power dissipation should be declared as 2Watts@60C flashlight temp. FET can handle higher temperature, about 150C, but rest of electronic parts (caps,ICs...) which are on same pcb are rated to ~105-125C.

The reason for high Rth value is bad thermal conductivity of FR4 material combined with small cross section and relatively long distance through which heat must travel, and very small contact area between driver GND ring and pill.

Copper layers help a bit, but the main problem is that FET drain pad, which serves as cooling pad, must be isolated from GND ring - no direct copper thermal path is possible.

 

If you put MOSFET on LED PCB like mosX which has very high thermal conductivity, Rth between FET and flashlight becomes very small,<1C/W!

Thermal conductivity of ceramic dielectric is much higher than FR4 material, thermal path is much shorter(1.5mm), and cross section area is bigger. All this gives much lower thermal resistance.

If we do the same calculation as above for mosX PCB with Rth=1C/W, for 2Watts of heat in FET, FET temperature will be Tfet=60C+1C/W*2=62C! Temp. increase is just 2C, compared to 40C for FET on driver PCB.

 

I can see why some people intuitively think that it's better for FET to stay on FR4 driver PCB because it's "isolated/protected" from LED heat, but remember that LED PCB/shelf is also a great heat sucker!

As math shows us, FET on driver PCB would get much hotter (and by only its own generated heat), because it's too thermally isolated from flashlight cooling surfaces. Heat builds up as it can't go anywhere efficiently. FET on LED PCB would run much cooler because despite the heat generated by surrounding LEDs, there is still plenty of cooling ability caused by very low thermal resistance of LED PCB/shelf.

 

For those who still are not sure about all this, one little thought experiment: take two 20mm LED PCBs with any LED and place one on cold (20C) wooden surface, and other on hot (60C) aluminum/metal surface.

Drive LEDs with same current/power, let say 3Watts. What do you think, which LED will get hotter after few minutes?

(LED on MCPCB represent FET/heat generator, wooden surface is FR4 driver pcb, hot metal surface represent LED MCPCB)

 

 

 

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My flashlights are liquid cooled at 98.6 degrees F. Sometimes the heat sink complains though.

DB Custom
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Thanks Neven, that really clears it up for me. I know there are Toshiba MOSFET’s that have an additional thermal pad on top for just this sort of occurrence but adding a heat sink can be problematic as there is often very little space.

Thank you for going to the trouble. Appreciate it. Wink

contactcr
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Finally got my 3x White Flats in my 18650 C8F. I had a virgin PCB from the 6 LED light I built. It was much easier to reflow on a new PCB with less solder and some flux.

With extra long 20 gauge wires (for re-flashing) and MTN-17DDm FET+1 driver. Both ends bypassed.

Get about 13.x amps on a lightly used VTC5D for 144kcd – way more satisfying than the shaved SST-20’s that were in there before.

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