Flashlight concept #2 - the ideal Luminus SBT-90 Gen. II light

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Lux-Perpetua
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Flashlight concept #2 - the ideal Luminus SBT-90 Gen. II light

Hello everyone,

We have seen some interesting new flashlights with Luminus SBT-90 Gen. II, e.g. Acebeam's K75 or Nightwatch's NI40. While Acebeam's K75 is too large and too expensive in my humble opinion, the NI40 has a more interesting size but lacks some features like 21700 compatibility, a wider reflector, a nice UI with configurable modes and a good thermal regulation.

With these things in mind I would like to discuss ideas what the ideal SBT-90 Gen. II flashlight should look like and what features would be reasonable to have. Personally, I'm quite thrilled by a size like HaikeLite's MT07 Buffalo but with an up to date battery carrier for higher currents.

My most important questions right now are:

  • What is a reasonable reflector diameter size taken the LEDs die size and lm/W ratio into account?
  • What driver would suit best for this LED? Provided we used a battery tube of 3x 21700 batteries, would a 3s buckdriver (12V) be more useful for a good contstant regulation at less than maximum power or should we better go for FET with 3 cells in parallel and push the SBT90 Gen. II to its very limits?
  • If using FET, how can we deal with the extreme excess heat that is generated with > 20A current?

 

Desired Hardware Specifications

  • Luminus SBT-90 Gen. II (3V)
  • Titanium/stainless steel bezel
  • 75mm SMO reflector
  • Aluminum Tube (with 3x 21700)
  • E-switch
  • Efficient 3s buckdriver or max.power 3p FET driver
  • Integrated USB-C port (in thread section), maybe with powerbank feature

User Interface

  • Andúril/NarsilM firmware
  • Individually configurable thermal regulation

 

hasddie293
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Interested!

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2. Durabillity
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5. Price$$$

Th558
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I would like to see one like this and a smaller one like the GT Mini/NI40 combined. I would prefer one cell like the Noctigon K1 but they’ll probably be lights like that soon anyway. Maybe even the K1 will have this LED. I hope so anyway. Would 4 18650s or 3 21700s make more sense? I think we should make the fins as thin as possible so we can increase the number of them but don’t put them too close together unless there’s a fan

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Lux-Perpetua wrote:
  • What driver would suit best for this LED? Provided we used a battery tube of 3x 21700 batteries, would a 3s buckdriver (12V) be more useful for a good contstant regulation at less than maximum power or should we better go for FET with 3 cells in parallel and push the SBT90 Gen. II to its very limits?

You can have both efficient and powerful buck driver. Check this thread from Lexel: Lexels driver compilation. He is developing a 40A CFT-90 buck driver for BLF GT, he has a starting point so.

Yokiamy
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This would make a very nice thrower, or should i say, cell drainer ?
interested

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maukka
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Th558 wrote:
I would like to see one like this and a smaller one like the GT Mini/NI40 combined.

Maybe the Acebeam K30 GT?

twisted raven
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I dunno K75’s size is pretty ideal for this emitter. It’s a large emitter and needs a large reflector. It is also a power hungry emitter, and sacking more potential power capacity for a slightly smaller handle wouldn’t make much sense. In small sodacan lights where portability is a concern, 3×18650 tubes make sense, but not for large dedicated throwers. If going with a 3×18650 tube, I would make the reflector much smaller, and just turn it into a combo flood/throw light— “relatively floody.”

The only thing I don’t like about the K75 is that its heat sinking leaves a lot to be desired. While looking good, the random fins halfway up the reflector don’t do much good, and there’s not enough fins down near the neck of the light where they should be. The light gets hot fast— real fast.

I would love the SBT90.2 in something like a maxtoch XPro host, but I don’t think 2 21700s in series would be as ideal as 4 18650s in parallel.

What I think would be a novel concept is something akin to a dedicated handle searchlight like an updated Klarus RS80 with its large 6×18650 battery pack, or even a 6×21700 battery pack, but shape the host in such a way that it’s as compact as possible, and with a singular, large reflector, and then give it a nice handle that is balanced. That way you make it more ergonomic, but while being beefy enough and has enough capacity for turbo.

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Very interested in this. I have the Nightwatch and the beam is great.

Lux-Perpetua
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twisted raven wrote:
I would love the SBT90.2 in something like a maxtoch XPro host, but I don't think 2 21700s in series would be as ideal as 4 18650s in parallel. What I think would be a novel concept is something akin to a dedicated handle searchlight like an updated Klarus RS80 with its large 6x18650 battery pack, or even a 6x21700 battery pack, but shape the host in such a way that it's as compact as possible, and with a singular, large reflector, and then give it a nice handle that is balanced. That way you make it more ergonomic, but while being beefy enough and has enough capacity for turbo.

That's an intruiging idea. How about using the Sofirn SP70 host design (including some upgrades like actual 2x21700 support and SMO reflector)? Certainly, it would need a different driver, too.

 

maukka wrote:
Maybe the "Acebeam K30 GT":http://www.acebeam.com/k30-gt? 

Wow, I wasn't aware of the K30 GT yet. However, I think something of size in between K30 GT and K75 could be worth aiming for, couldn't it?

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I like the 3*21700 design., but 2*21700 long tube is also interesting

For driver i prefer buck driver more, 3v@20A is 12V@5A, most(if not all) 21700 battery can handle fine, and moreover, we can drain every last juice of battery.

I dont think i will ever need powerbank feature, it’s a nice thing to have, but i think it may rise the cost significant

Forgot my pen

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Cool Haikelite is doing it.
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I hadn’t seen the new acebeam k30gt yet either. My take: though I like the size and 3x cell layout, there are not enough cooling fins, and no 21700 support. It s very similar in head size and length to my catapult v6 which I really like for a jacket pocket light, and the bigger handle of the acebeam should fit the hand better.

.25 lux on an object is not bright enough for me at longer longer distances,since I live and work on a large ranch with both livestock, predators, and big game, so putting lots of lux on an object while far away is paramount..so my acebeam k75 is nice- I use it all the time. It just doesn’t handle the heat well enough, and though it is not that heavy, it is a little bit unwieldy. I’ve often thought that a vertical handle, and more effective cooling fins would make this light better.

Lux, your concept intrigues me. Nobody can seem to get it right with this led. What if you could buy different sized heads to fit on the same handle? Led and driver stay with the handle. Heat transfer would be an issue, but is there a way to make heat transfer to the head better?

My idea:
A configurable body. A lightweight, highly finned head housing a 4 1/2 inch reflector that can either be screwed to a battery handle just like our flashlights, or a separate battery pack on the belt, or a battery pack below a very ergonomic handle similar to modern cordless drills. Hmm, stuff to think about. I can do cad design, and could always 3d print plastic handles and such for prototyping, but dont have machining access anymore.

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pearlriver wrote:
Cool Haikelite is doing it.

Doing what?
tekwyzrd
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So, a courui d01 with 21700 in place of 18650 and added features…

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Tom E
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3 40T's would be interesting for this LED for sure - great power, decent capacity. Expect 30+ amps draw I suppose?

The MT07 is a beast, though a little big/heavy for me, but a reduced diameter battery holder with 3 21700's would be an advantage.

PearlRiver - what exactly is HL doing?

Th558
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maukka wrote:
Th558 wrote:
I would like to see one like this and a smaller one like the GT Mini/NI40 combined.

Maybe the Acebeam K30 GT?


Looks like a nice light. I’m sure it will do over the stated 260kcd.
I’m talking about something a bit more compact though. IMO it’s a bit heavy for pocket carry. I have an NI40 coming but would prefer a 21700 side switch anduril light which is a bit shorter and lighter.
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I'll 2nd that! I find the easier I can carry a light in my pocket, the more use it gets.

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I say, the BLF GT4 host with single GT reflector and SBT90.2 Big Smile

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Tom E wrote:

I'll 2nd that! I find the easier I can carry a light in my pocket, the more use it gets.

The best flashlight is the one that you always have with you. Wink I fully agree with you except for one thing. I have some doubts that SBT90.2 is an emitter that fits well into a pocket- / EDC- flashlight. I see following challenges here but please feel free to correct me:

Price/Size ratio:

Usually, EDC lights have a quite sensitive pricing level. With a $ 35.00 LED inside the price is likely to reach "premium" areas.

Size/Heat ratio:

SBT90.2 is a monster in terms of excess heat, being driven up to more than 20A. The smaller the flashlight gets, the more difficult it will be to transfer and dissipate the large amounts of heat. Unless driven at lower currents with more efficiency, maybe other LEDs would suit better?

LED/Reflector Size ratio:

With its die size, footprint and domeless layout the SBT90.2 seems to be best for throwers. Since these specs would collide with a small sized reflector, there might be alternative, cheaper but also brandnew LEDs like SST-70 or XM-L3 more appropriate? However, maybe with the right TIR lens the lack of a large diameter-reflector could be compensated somehow.

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mr_magoo wrote:
pearlriver wrote:
Cool Haikelite is doing it.

Doing what?

Lux_perpetua is Haikelite?? Or it look more alike ? Nevermind…

Have anyone try put this sbt90.2 to convoy L2? Does is fit? Just for a try with convoy driver…who know it will be much so low heat? Idk.

I’m just curious how the 20+ amp passing and where the heat will dissipated. I think most about current flow should be regulated constantly with rise with temperature. Or is there any better regulator out there for sbt90.2?

In search of the most ideal flashlight in town:
1. BRIGHTNESS
2. Durabillity
3. Design
4. Quality
5. Price$$$

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hasddie293 wrote:
Lux_perpetua is Haikelite?? Or it look more alike ? Nevermind...

Not even remotely.... He's also not working for any flashlight maker.

He's just another guy who is enthusiastic about these tiny little devices we all call `flashlights`. Call me nitpicking or whatever but mostly I've got something to rant about a new model. Sometimes it's the UI, sometimes the chosen emitter, more often it's the thermal regulation and sometimes it's just details in the design that I cannot fully agree upon. With so many great minds here on BLF I started to ask myself the very question if we could put our minds together, develop some nice concepts and see if we can encourage one or more manufacturers to follow our ideas. Rest assured, some flashlight manufacturers will surely have a look onto BLF's "think tank" even without being actively involved. Smile

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I see a few mentions in this thread but 3S and buck driver do not equal 12V

hasddie293
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maukka wrote:
Th558 wrote:
I would like to see one like this and a smaller one like the GT Mini/NI40 combined.

Maybe the Acebeam K30 GT?

K30 gt price is JAW-DROPPING Does making higher price solved the problem? Bluffing.

In search of the most ideal flashlight in town:
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2. Durabillity
3. Design
4. Quality
5. Price$$$

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contactcr wrote:
I see a few mentions in this thread but 3S and buck driver do not equal 12V

Well, yes and no. I was only referring to three cells in series (3x 4.2V = 12.6V) but the buckdriver will convert it accordingly.

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Lux-Perpetua wrote:

contactcr wrote:
I see a few mentions in this thread but 3S and buck driver do not equal 12V

Well, yes and no. I was only referring to three cells in series (3× 4.2V = 12.6V) but the buckdriver will convert it accordingly.

It still doesn’t make sense. You can do a 9V LED with 3S but not a 12V and if you are going to use buck for anything less than 9V why would you choose 3S? You need 4S for 12V out

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Sorry, I think we misunderstand each other completely right now. I never meant to talk about a 12V LED. Instead I was talking about a 3V LED that requires a buckdriver to convert the voltage of 12V (3x 21700 in series) down to the 3V LED voltage. I hope it makes sense now. Sorry for the confusion.

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Lux-Perpetua wrote:

Sorry, I think we misunderstand each other completely right now. I never meant to talk about a 12V LED. Instead I was talking about a 3V LED that requires a buckdriver to convert the voltage of 12V (3× 21700 in series) down to the 3V LED voltage. I hope it makes sense now. Sorry for the confusion.

If that’s the case (which seems pretty slim chance of happening) you should do 3s2p 18650 and make a long tube where you can choose to put 2, 4, or 6 batteries in and scrap the idea of charging.

Even better since we are dreaming make a buck-boost driver and have either two tubes or an extension tube so people can do 3p or 3s2p or anything in between!

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maukka wrote:
Th558 wrote:
I would like to see one like this and a smaller one like the GT Mini/NI40 combined.

Maybe the Acebeam K30 GT?

Wow first time I’ve heard of this new light. I was going to say I prefer a more compact 3×18650 since 3×21700 is about the same diameter as 4×18650. I also like the SP70 and L6 form factor. Maybe even a 32650 battery host would be one of a kind. I would love to have a long base ball bat like flashlight for self defense.

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Lux-Perpetua wrote:

Tom E wrote:

I'll 2nd that! I find the easier I can carry a light in my pocket, the more use it gets.

The best flashlight is the one that you always have with you. Wink I fully agree with you except for one thing. I have some doubts that SBT90.2 is an emitter that fits well into a pocket- / EDC- flashlight. I see following challenges here but please feel free to correct me:

Price/Size ratio:

Usually, EDC lights have a quite sensitive pricing level. With a $ 35.00 LED inside the price is likely to reach "premium" areas.

Size/Heat ratio:

SBT90.2 is a monster in terms of excess heat, being driven up to more than 20A. The smaller the flashlight gets, the more difficult it will be to transfer and dissipate the large amounts of heat. Unless driven at lower currents with more efficiency, maybe other LEDs would suit better?

LED/Reflector Size ratio:

With its die size, footprint and domeless layout the SBT90.2 seems to be best for throwers. Since these specs would collide with a small sized reflector, there might be alternative, cheaper but also brandnew LEDs like SST-70 or XM-L3 more appropriate? However, maybe with the right TIR lens the lack of a large diameter-reflector could be compensated somehow.

Realistically all true, but I don't really care - it's for me, not the general public cool. My problem would be fitting the 20 mm MCPCB in a small head, and getting the reflector hole to fit around this huge LED. There are XHP70 tactical lights around, little bigger maybe than pocket carry, but similar argument could be made against those but they do tend to have boost drivers that limits the amps considerably, least considerably from what we typically do with a FET driven XHP70.

I'd probably go with a larger pocket carry light like the Lumintop SD26 - takes a 26650, has a great small SMO throw reflector, etc. Vinh used to rave bout this light and for good reason. I got one all modded up runnning NarsilM - outstanding quality and performance. Shame it's apparently dropped now - great light, should have done better and been rev'd up. The craze of TIR optic multi-LED lights kind of killed it. Here's the page on it: http://www.lumintop.com/sd26.html, broken links to buy one.