# [PART 1] Official BLF GT Group Buy thread. Group buy officially closed! Lights shipping.

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Texas_Ace
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The Miller wrote:
Funny nobody seems to have picked up my long post, so here goes: OK I need a good render as close to what it will be next week. Decided are TUBE: 2 * 4 18650 / LED XHP35hi (bin etc to be discussed) Because US holidays, both companies needed for more in depth reflector design are to be contacted Tuesday. Till then, would the smaller finning of the Q8 around the switch not look a bit better and cool a lot better, while not adding costs nor weight? This could be implemented in the render then right? Also a few fins hgher up the head are needed, since we need anto rolling anyways, I can live with the fin design of 5ar, but maybe it could be done in such a way less material is used there.

I think besides the minor fin changes the existing renders by 5AR are the best bet, I don’t see many major changes happening externally until we have found a reflector and figured out if cell carriers will be used. Both of which have to wait until we find a manufacture.

Is it even worth adjusting the fins for the initial presentation to the company?

Pm incoming…

KawiBoy1428
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Mr. Miller put me down for another GT for a total of (2) please, thank you very much!

KB1428 “Live Life WOT

Nicolaas
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Theodore41 wrote:
Nicolaas wrote:
Enderman wrote:
Nicolaas wrote:
No big fins please, no need when driving an XHP35 HI at 2,5A+. This light will have more then enough mass to absorb the majority of the heat produced. . Big fins are needed only when multiple emitters are driven hard and we are not going that way, right? . Grtz Nico
An XHP35 at about 3A will be producing over 40W of heat, The “mass” of aluminum in the body does not magically “absorb” heat and make it disappear. You cannot destroy energy like that. A piece of metal is what contacts air and transfers heat away by convection. Fins speed up this process, otherwise with enough heat the flashlight body will just keep getting hotter and hotter until you cannot hold it anymore. Also, LEDs output more light at lower temperatures.

Care te explain?

The XHP35 HI is a 12 V emitter, that will operate at around 2,5A.
Doesnt that mean 12*2,5= 36Watts in total, a part of which is being convcerted into light?
Lets be generous and suppose the Led has a 15% efficiency, that would leave 30,6 watts of generated heat.

Or do I calculate this wrong?

Grtz
Nico

http://www.ledsmagazine.com/articles/2005/05/fact-or-fiction-leds-don-t-...

.
.
.
Thanks for confirming my calculation!
.
So, this light will produce around 30 watts of heat, instgead of the aforementioned 40 watts.
Question: will it be able to absorb the heat produced at turbo without more cooling fins for more then say 10 – 15 minutes or will it get to hot to handle?

Maybe someone on the forum could do the maths?
I can’t…….
It will be strongly depending on ambient temerature as well, so if calculations at different temperatures could be done?

Grtz
Nico

Texas_Ace
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Nicolaas wrote:

.
.
Thanks for confirming my calculation!
.
So, this light will produce around 30 watts of heat, instgead of the aforementioned 40 watts.
Question: will it be able to absorb the heat produced at turbo without more cooling fins for more then say 10 – 15 minutes or will it get to hot to handle?

Maybe someone on the forum could do the maths?
I can’t…….
It will be strongly depending on ambient temerature as well, so if calculations at different temperatures could be done?

Grtz
Nico

The L6 comes stock with around 40W and about 1/3 the amount of metal in the head and I am going to guess roughly the same amount of surface area.

It manages to run until the batteries die without overheating on turbo.

mdeni
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Texas_Ace wrote:
Nicolaas wrote:

.
.
Thanks for confirming my calculation!
.
So, this light will produce around 30 watts of heat, instgead of the aforementioned 40 watts.
Question: will it be able to absorb the heat produced at turbo without more cooling fins for more then say 10 – 15 minutes or will it get to hot to handle?

Maybe someone on the forum could do the maths?
I can’t…….
It will be strongly depending on ambient temerature as well, so if calculations at different temperatures could be done?

Grtz
Nico

The L6 comes stock with around 40W and about 1/3 the amount of metal in the head and I am going to guess roughly the same amount of surface area.

It manages to run until the batteries die without overheating on turbo.

This should settle it.
teacher
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Texas_Ace wrote:

The L6 comes stock with around 40W and about 1/3 the amount of metal in the head and I am going to guess roughly the same amount of surface area.

It manages to run until the batteries die without overheating on turbo.

Yep, that is a fact about running the L6 in Turbo mode… no ‘heat issue’ at all till the batteries croak.
So, that being said; overheating should definitely not be an issue with this proposed light.

EDIT………..

mdeni wrote:

This should settle it.

You never know how a horse will pull until you hook him up to a heavy load./"Bear" Bryant

.................................. "Slow is Smooth, Smooth is Fast" ...................................

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Jerommel
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Texas_Ace wrote:

I think besides the minor fin changes the existing renders by 5AR are the best bet,

Why bet?
Frankly i still think it’s very Chinese looking and to me it’s a bit of a put off.
And that’s why i didn’t contribute anything here in the past days.
I’m quite happy with the 8× 18650 config, and i guess the battery carriers are pointless too when there will be no short tube version, so that makes things simpler too.
Quote:
I don’t see many major changes happening externally until we have found a reflector and figured out if cell carriers will be used. Both of which have to wait until we find a manufacture.
It’s the head basically.
I think it’s plump and not integral with the rest of the looks.
Jerommel
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Say, why not base the looks on the Convoy L6 ?
Not my favourite design, but at least head and tail are in harmony.

Texas_Ace
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Jerommel wrote:
Say, why not base the looks on the Convoy L6 ? Not my favourite design, but at least head and tail are in harmony.

This is more or less what the design was inspired by actually. We didn’t want to copy it anymore since convoy is not making it and it would suck to flat out rip off the design.

Plus adding fins only adds weight to an already very heavy head.

teacher
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Texas_Ace wrote:

I think besides the minor fin changes the existing renders by 5AR are the best bet
Good….. because personally, I think the design looks great!
I hope it does remain basically unchanged……

You never know how a horse will pull until you hook him up to a heavy load./"Bear" Bryant

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The Miller
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wowowow, it is too much L6 for me as it is
the L6, blocks at the top and tail, completely different blocks on tube, the anti roll cut outs have nothing to do with any other part. I use it in the dark and am happy I only see the light it produces, the rest I do not really care about.
But that is me, “over smaak valt niet te twisten” or “no point in arguing over preferences” function on the other hand, yes, that is objective (or well should be ) thus seeing the current render, from top downwards, there is a straight line that goes on where the anti roll fins are. I think that this could and should be done smoother, so less deep fins there, maybe 3 less deep fins with little wider cut outs for anti roll.

crude sketch

Texas_Ace
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We could eliminate the fins in the anti-roll cutouts as well since they are just cosmetic. The anti-roll couts could also be widened and spread out a bit further IMHO. So instead of 8 cutouts, reduce it to say 6.

The Miller
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that “tactical ring” at the tail, would that not suffice as roll prevention?

teacher
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Is the “tactical ring” going to be removable?

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Texas_Ace
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The Miller wrote:
that “tactical ring” at the tail, would that not suffice as roll prevention?

If it was installed it migh, although I figured it would be removable like the S70 / L6.

the issue is that with that much weight and size in the head it could easily overpower the tactical ring if the surface is not perfectly flat.

But then if they are not “lined up” it may not matter and it could roll anyways, so maybe the tactical ring is the best idea.

The Miller
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That would allow the head to follow the contoures of the reflector close by, less material, less weight, and elegant looks right?
maybe just screwing in one of those nuts for thick lanyards in the tripod mount would prevent rolling too.

Jerommel
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The Miller wrote:
wowowow, it is too much L6 for me as it is
the L6, blocks at the top and tail, completely different blocks on tube, the anti roll cut outs have nothing to do with any other part.
Same as this preliminary design…
Yet it looks… O well, the L6 is not exactly beautiful design either…
Quote:
I use it in the dark and am happy I only see the light it produces, the rest I do not really care about.
So let’s just stick with the first idea then?
I find that rather strange.
Quote:

But that is me, “over smaak valt niet te twisten” or “no point in arguing over preferences” function on the other hand, yes, that is objective (or well should be ) thus seeing the current render, from top downwards, there is a straight line that goes on where the anti roll fins are. I think that this could and should be done smoother, so less deep fins there, maybe 3 less deep fins with little wider cut outs for anti roll.
I don’t know about you,but when iḿ looking to buy a light, the exterior matters.
In fact, it’s the only thing you see when browsing, and a light either appeals to you or it doesn’t.
This decides the purchase, except when there’s no other choice and you really need it.
Quote:

crude sketch

It doesn’t get any prettier with more thinner and deeper fins…
And considering the surface area of the GT, it’s not necessary either.

But hey, we have this decided (correct me if i’m wrong):

8 × 18650
XPH35
120mm reflector.

About anti roll:
I put lights on their heads on a table, not on the side.
None the less, it is better when it can not roll off the table for sure.
But i don’t like the sharp points resting on the table, it should be flatter i.m.o.
Also, every sharp edge will result in anodizing wear.

Look, i just say it would be good to have a couple of designs to choose from rather than stick with the first preliminary ideas.
I don’t know about you guys, but apart from being a portable light source, a flashlight is also a pretty piece of metal that can look really nice, which makes them desirable objects.
But apparently you and TA don’t care too much about the looks, so why not leave this more open for discussion for those who do care.
I mean, i fail to see the reason to stick with this design.
And i’m not gonna push my design (several pages back), but rather i would like to share thoughts about it here and have 5ar look at the options too.

One more thing:
Battery carriers.
WHY??
I can tell you why not though…

Alright, i’ll go see what i can do with my image editer, but things like fins and knurling are hardly possible…

Later,
J.

Enderman
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Nicolaas wrote:

Care te explain?

The XHP35 HI is a 12 V emitter, that will operate at around 2,5A.
Doesnt that mean 12*2,5= 36Watts in total, a part of which is being convcerted into light?
Lets be generous and suppose the Led has a 15% efficiency, that would leave 30,6 watts of generated heat.

Or do I calculate this wrong?

Grtz
Nico

If they end up doing direct drive (which I don’t think will work very well due to the voltage being too high) it will draw way more than 3A, I haven’t seen any tests done over 3A for the XHP35 so idk what happens.
If they use some current regulation and limit it to 3A, then it will be drawing slightly over 15V

So that’s at least 45W total, and 15% efficiency is a good estimate, so about 35-40W into heat considering 45W is an underestimate.
Also, the hotter the LED gets the lower the efficiency, so without proper cooling the LED could be running at 85C or even more which means less light and more heat.

If somehow they manage to do DD without the LED burning up then it will be using almost 17V and probably like 5+ amps, so a LOT more heat than just the little 3A test from above.

MortyDuck
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YES!! Thinner and more fins looks awsome!! ..and it will cool things down, it’s the way fins work..

I liked that render to the left in post#1212 MUCH MORE than the original..
IMHO

"Do to others, what you would like others do to you.."

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jmpaul320
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interested

Would you mind keeping the wrong flashlight?
Best wish, May
Tmart service team

Soumil wrote:

PLEASE HELP ME GEARBEsT! IM LITERALLY CRYING!

MortyDuck
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And I do think that if designated design is cooling things down MORE than it really needs to do, it will be a far better way to go.

If your dragster car cools better in it’s engine..and if you want to change to a bigger turbo, it’s just to do it! And only that….it will be a big advantage it think.
If you “catch my drift”

"Do to others, what you would like others do to you.."

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Texas_Ace
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More cooling is better for sure but with a light this massive weight is a large factor that has to be considered. You also have to factor in things that normal lights don’t have a big issue with like the likeliness of it rolling off a table ect.

Adding more fins adds more weight, this is something to be carefully balanced.

I personally like fins and the aggressive look. I think the L6 is one of the best looking lights out right now. Others firmly disagree.

Since this is a cosmetic issue it truly is personal preference and comes down to what each person likes.

I can live with a more basic design as long as it doesn’t give up any performance.

That said I truly like the basic layout of the current renders. It looks big and powerful, which is exactly what it is. The fining change and some adjustments to the anti-roll cutouts I have wanted for awhile but it was not worth messing with till we sorted some other things out first.

Being that this is a cosmetic issue, as long as the layout is unchanged, I can really go with whatever is the most popular look for pure aesthetics. Changing to a 26650 or a different tube on the other hand is a performance issue and that is something that needs to be backed up with logical reasons, which I have not seen.

Enderman
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Ok guys so I have done some calculations trying to figure out exactly how the dimensions of the reflector would work.
This isn’t a ray trace and it will not show how one reflector might perform better than another (based on size of LED and distance from LED to reflector curface)
But what it can do is show you how tall or wide you might want your reflector, and the distance from the LED to the closest point on the reflector (making this bigger will reduce corona around the hotspot for a more collimated beam)

Here are the equations you can input to desmos calculator (you can copy paste these right in, one box each):
https://www.desmos.com/calculator
y=s\cdot x^2-\frac{.25}{s}
y=-x-\frac{.5}{s}
y=x-\frac{.5}{s}
s=0.03 (for this one you will want to click the number at the end of the slider and set it to 0 <= s <= 0.2 step=0.005)
y=0
-60 < x < 60 (diameter that you want your reflector to be, in this case 120mm) (you can also just do lines like in the image if you want to see better)

Now what you can do is move the S slider back and forth to change the size of the reflector.
You will see that the reflector is sitting slightly below y=0, this is because the LED will be centered at (0,0) and anything below y=0 will not be used at all by the LED, since the LED cannot project light behind it.
Changing S will adjust the shape to be deeper or shallower, and you can see the height of the reflector is from y=0 to the point where the parabola intersects the vertical X lines we put in.

——————————————————————————————————————————————————————————————————————————————-

In the screenshot I took, the reflector is 100mm deep, 120mm diameter, and it has almost 34mm opening at the bottom. Green and blue lines are unnecessary but they show that the 45 degree tangent is always on the line y=0, so no matter how big or small your make your reflector it will always be focused at the LED at 0,0. Getting the height is really easy then, since you start at y=0 and measure upwards.

——————————————————————————————————————————————————————————————————————————————-

Another way you can use this set of equations is by setting y=the height you want your reflector to be, and adjust S to see the diameter (where the parabola intersects the y line) and that will show you the shpae of the reflector, how much of it is being used, etc. Remember the part of the parabola below y=0 will never be used for reflecting light, so it is just dead space.
Hopefully this helps someone design their own reflector or something

G0OSE
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I must admit, I kinda agree with some on the design. I did wonder why everyone ‘raved’ about it so much, yes the renders quality is very impressive – he/she is very talented, but it’s it basically is an L6, if we add more fins it will be an L6! (or the daddy of, nothing wrong with the L6 design – but this is a bit too similar for me)
I think we got a bit carried away with that ‘quality of render’, rather than discuss what design/features etc are wanted/needed, then making some preliminary sketches (simple line drawings, not renders) – after that , maybe voting on a ‘design’ by one of the guys who are up for it/are good at this sort of thing Not go over the top btw, it’s not a competition – maybe just choose 3 people to do the ‘design’ challenge, all to the same specs/sizes obviously.
Just an idea.

Oh, and btw I must just re suggest an idea from an earlier post – could we please try to work in another tripod mount hole at the back somewhere? it’s not for a tripod…. it will allow that little cheap adapter (from my post earlier) to screw in an enable many thousands of different shoulder straps (from cameras etc), which would also be very strong.

# The BLF Flashlight / Accessory / Battery / Spares Retailers Thread with Discount Codes

Texas_Ace
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Most of the issues early on were the design changes were not just cosmetic but functional (such as changing the cell layout). So we could not actually focus on the cosmetic design. I always knew that some revisions would be needed but a lot of them can’t be finalized until we pick a manufacture and reflector so it was no hurry to worry about them before other issues.

MortyDuck
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I’m to much of a noon…at this point..but is it so hard to find a reflector or a reflector manufacturer how can make wath we need?
I bet Simon at Convoy know..but do we know simon. Maybe he can guide us in the right direction? And if some of you laughing at this post..consider that first sentence one more time. Lol

"Do to others, what you would like others do to you.."

-MortyDuck-

MortyDuck
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And if fins are not needed in the way I thought…the first design is a killer anyway!!
GREAT JOB by 5ar!!!! Thumbs up

"Do to others, what you would like others do to you.."

-MortyDuck-

vol
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I would like to be added to the list to buy this light. It’s gonna be awesome.

The Miller
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MortyDuck wrote:
YES!! Thinner and more fins looks awsome!! ..and it will cool things down, it’s the way fins work..

I liked that render to the left in post#1212 MUCH MORE than the original..
IMHO

Well it is a kolourpaint hack and slice work, unfortunately not a render would be a lot of work making it into one.
.
.
.

Jerommel wrote:
a lot of input

I do care, but comparing the current render to the first, I can more then just live with it, the flat area and the shape of that area (and at the tripod mount) is enough to give it a bit of Q8 family resemblance. What I mean with “no point in arguing about preferences” is not that I do not care about the GT looks. I do not care about the L6 looks since I use it for its beam and accepted that i do not like how it looks before I ordered it. But seeing the L6 come together, having great liking for J-Dub74 and liking Simon and seeing lots of people being excited about it gives it a certain charm and beauty that goes beyond my personal preference

Of course the GT is different, and there is another flow here compared to the Q8.
With the Q8 Djozz made a photoshop changing a SRK and I took that and crudely made it and we discussed a lot here on BLF, after that we kept on explaining to Thorfire what I saw in my head and what I tried to draw, the result is exactly what I wanted in my head. But that is a lot of “me, my, and I’s” so now TA really likes the L6, lots of people do and 5ar came with a render heavily L6 influenced. I did get the more Q8 like section in switch/tripod mount section so happy.
Of course I would have loved to see the anti roll cut outs to be the same shape as the Q8 cut outs are. But it is not my project, it is ours
.

Enderman wrote:
NICE INPUT

COOL!
I added your whole post to post 5 (now dedicated to the reflector, thanks!
The Miller
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vol wrote:
I would like to be added to the list to buy this light. It’s gonna be awesome.

Welcome to BLF!
Yes will add you and others later!

G0OSE wrote:

Oh, and btw I must just re suggest an idea from an earlier post – could we please try to work in another tripod mount hole at the back somewhere? it’s not for a tripod…. it will allow that little cheap adapter (from my post earlier) to screw in an enable many thousands of different shoulder straps (from cameras etc), which would also be very strong.

wait, you want two tripod mounts?
There is a connection point for shoulder strap and a tripod mount planned, sure a second would be a good idea?