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

Tony Stark works at Wuben right :wink:
Nothing wrong with brainstorming IMHO when something is decided it should be a real group thing.
This is what makes this GT so early already (and the Q8 as well) so cool of a project!

Indeed the last few ideas have actually been things that could be used, if it was deemed necessary.

Although before we try to change things, I am still at a loss for what is wrong with the 4/8x 18650 tube? What doesn’t it do that these other ideas would?

Basically, what is better about the latest round of ideas? All I see is the inability to use 8X cells if someone so desired. Why not simply only run 4 cells in the 8 cell tube?

acutally I Like this idea, 2s2p should be using, so that we can have either using 18650 or 26550, or both
2s 18650 is able to drive xhp 35

To me the 4/8x 18650 tube makes the most sense, period.
In addition, as far as I am concerned; it would be ridiculous to “change things” or even think about “changing things” unless the questions Texas_Ace asked above are answered in a ‘reasonable’ way that would appeal to the masses.

2S will not drive a XHP35 without a boost driver. We need 4S, this is non-negotiable since we can not afford a boost driver for the goal budget.

+1 :+1:

Cheers David

All the ideas are meant to reduce cost of the light, and keep it simpler. If it can be made with the carriers for a low price than that is fine of course. They seem pricey and complicated to the casual observer.

Well, 4/8x 18650 design compared to new 4x18650 design.

4/8x tube:
Advantage: more runtime with 8 cells.
Disadvantage: more total weight (if used with 8cells), thicker.

4x tube:
Advantage: smaller, less total weight (compared to 8 cell setup)
Disadvantage: not being able to run it with 8 cells thus having less runtime (compared to 8 cell setup).

What doesn’t change:
Runtime when 8 cell tube is used with only 4 cells.
Weight when 8 cell tube is used with only 4 cells. (oke, weight is reduced slightly)

Personally, I dont care, just throwing out ideas. :smiling_imp: :beer:

How can I get into this buy?

Why not?!
This is a nice “Bimmelglocke”: Der Bimmelglocken-Thread | Taschenlampen Forum

Two 4 series carriers makes the most sense.

For me, personally, I don’t see why we don’t just have a dedicated 8 cells. It’s a search light, it’s gonna need run time to be used as it’s designed. There are perfectly adequate cells available for very cheap monies, no more than $40 for 8 really good high capacity cells can be found easily. This would have the absolute maximum effects, delivering BRP without a hiccup. (Balance, Runtime, Power). I bought the extension set for the TK61, ran 8 cells, didn’t have a problem with it. That was a much higher current light and it worked out fine.

As a comparison factor, the battery tube with proprietary cells for the TN42 is about $70, for the proprietary battery pack alone (4 cells)

While I do like the IDEA of everyone contributing on the making of a light from the ground up, I’ve seen repeatedly where it’s not sound business practice. A team should get together, decide the parameters, have the light made, then offer it for sale. To me that ensures optimization, without long delays in argument while ideas get tossed around like a beach volleyball. I’ve seen the open thread idea hold up multiple lights and even kill off a couple entirely. Seems funny that people are willing to get upset because they didn’t get what they wanted, but Nitecore, Fenix, Surefire, MagLite, Thrunite, Solarforce, EagTac, ArmyTek, SupFire, Olight, 4Sevens…. they build what they want and offer the lights for sale, they don’t take stinking polls! And most of us here have those brands, never had a single bit of input on how they built the light.

Diversity can build strength and character, it can also break the core, polluting the purity of the concept. Field of Dreams said it , “if you build it, they will come…”

If you build it right, they will come in droves!

Absorbing a lot of heat is right but only until the material is thermaly saturated then only the surface will help dissipating the heat.

Making the finns smaler (~1,8-2,2mm thick and a bit higher ~10mm) would help. The distance between the finns should be ~2,5-3mm.
Making them even smaler would help with the heat but they would be to fragile. Not something you would want on your high quality flashlight.

And the further you get away from the led less heat will be dissipating. So the finns can get smaller and smaller. So that the head will not get bigger.

To abandon the finns on the GT is not wise (or to use the 5-6mm thick only 5-6mm high finns that you can see on the prototype picture). They look good but will not help much with the heat.
Here a small example:

on the left i have a 10*10cm alu plate. Put a LED on one side and use the back for heat dissipating. You get a surface amount of 100cm². On the right side i put only 5 10mm high finns on the plate. Now you got 200cm² of heat dissipating surface. If you increase the amount of finns to 10 the surface area increase to 300cm².
Now do that on your flashlight base where most of the heat is generated. And you will increase the surface amount by 100-300% and you will be prepared for new more powerfull LED´s.

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Did someone answer you?

…so we can bring the reflector in the dicussion again….feel bored about the battery case…

Post 1 =
Driver design
…………… Tom E Electronic switch driver for Narsil firmware
…………… Very low parasitic drain
…………… Able to run 4 and/or 8 button top 18650 cell(s)

Take a read of this, it shows the maximum fin optimization for heat transfer in natural convection which I mentioned somewhere earlier in this thread:
https://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&ved=0ahUKEwilvZuf6cHQAhUaS2MKHRyaBnwQFgg6MAQ&url=http%3A%2F%2Ffiles.engineering.com%2Fdownload.aspx%3Ffolder%3Dbb2a80cf-6107-4ac8-9393-e56b7f4ab41b%26file%3DBar-cohen.pdf&usg=AFQjCNHEDu4omd0YLwJZIO65PPe69NYUhQ&sig2=No5Bw0NRX7BwzrAwrp75OQ&bvm=bv.139782543,d.cGc&cad=rja
You could make the fins thick for durability like you wanted but space them out according to the most heat dissipation shown in this peer reviewed article :slight_smile:

TLDR: 8mm spacing is best, but you should read the article for learning purpouses :smiley:

OK

4 series it is, was and will be :wink:
I kind of thought Thijsco was trying to dobit with 26650 cells and if that would still be nice to hold I do not have an issue with doing that (a slightly fatter tube probably looks better too) now I see it was about 2 series, sorry, simple no :wink:

So this is a moment for a decision, a long 4x2 18650 tube it is, just as in the renders, compatible with Q8 tube and a 46mm driver
:smiley: done.

I saw 4 3400 Panasonic’s for $11,11 at Gearbest some time ago, so 8 cells should not be expensive of using notebookpulls free.

At this stage, without manufacturer even without led brainstorming is nice. Decisions will be made and if not all are happy about outcome so be it :wink:
More then seriously taking everything in and debate sometimes cannot be done and seeing how it went with the Q8 I have faith in BLF.
I know other groupbuys went different and I did what I think is constructive, doing it the way I thought it would be better.

Haven’t heared back from the software guys, haven’t headed back from the IM reflector guys. It seems a holiday in the US so I am not going to pursue it before Tuesday :wink:

So in the mean time, mind if I call the LED chosen and maybe talk a bit about cooling (since a good render is needed next week (I have a high end manufacturer who is willing to listen, the more concrete it is the better. And no I will not disclose name you have to wait a few weeks for that.

Badaboom what a long post
Oh and I will update list later

That fined design is hidieous. 13cm head 1kg aluminium needs fins? No freaking way. It will make it even heavier and way uglier.

The issue with fins is weight, I wanted more fins at first as well. Till I realized it was already a 3.3lb light as it was and adding fins would further increase that.

A 5lb light while it sounds good is simply not practical to use in the real world.

Plus the L6 handles the power surprisingly well, this light will have about the same surface area I figure and in stock form anyways put out a LOT less power.

For raw output and power dissipation we would really need to go with djozz box idea with a fan on a heat sink for the ultimate cooling (something I would love to work on after this).

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.
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Big fins are needed only when multiple emitters are driven hard and we are not going that way, right?
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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.

When the time comes, please put me on that list. :smiling_face: