less resistance I guess and a few mm saved
Love the super-deep heat sink fins. The GT4 has the most impressive heat sink fins of any flashlight I’ve seen or heard of I think.
Looks like were going to need 8 Button Tops? First thing I’ll change….if it’s so…
yeah and probably the most heavy head for a flashlight, i think it must weigh like 2,5kg alone just that… 
Aluminium is pretty lightweight though, that head is heavy but not excessively.
Can you imagine a brass GT4 (
), similar to this: https://budgetlightforum.com/t/-/56156. The brass MT03 comes in at 1450 g vs. the aluminum version at 620 g.
Partly to make sure that you use 8 cells, 4 cells would easily overload all but the best cells.
The biggest reason is to lower the resistance by removing the tiny spring in the carrier “button top”. Although they didn’t actually do that in the prototype even though I told them over and over what needed to happen. So like I figured, it promptly melted when I used it long term lol.
Although that carrier design is not final either, it needs a disc in the middle to keep the cells in place, right now they want to pop out the sides. It is lower resistance like this but I don’t think having batteries wanting to pop out of the carrier until it is inserted into the light will go over well.
WOW!
The amount of time/energy spent designing that head is impressive. I do quite like the idea of actively cooled lights but with Imalents new MS18 they finally got a super powerful system which appears to work wonders. The catch is the cost of it sounding very much like a hairdryer! I love how much work went into making such an amazing passively cooled system and from everything I’ve read by TA it appears to be one of, if not the best passively cooled lights ever. Well done everyone involved!
I’m super excited about this light also and can’t wait for more updates!
I’m not so sure about that. These heat sinks are shallow.
I agree. Doesn’t compare from what I can see. The only light I’ve ever seen that’s comparable is the old Olight X6
To me it's more like a super sized J20, reviewed here. The J20 is a great thermal design, one of the best.
Except for the fact, Tom, that in the J20 they didn’t connect the emitter shelf to the excellent cooling fins. After I fixed that for me and Richard the light performs quite well. 
Well it looked good anyways... 
I was think'n of your J20 mod/build but couldn't find the post(s). I knew you and Richard were involved in a great mod to one, just couldn't recall details.
For Richards I built a battery tube extension and a heat sink that filled the head. With the head hollow, the heat didn’t effectively reach those deep lower cooling fins. So the heat sink addresses this with the thick portion that sits above the head and makes contact with the underside of the emitter shelf, machined to fit into the head like a glove it takes the heat down into the fins and disperses it. The center hole is on a bevel to open it up at the bottom, both because of the further distance and lesser fins and because of the clearance needed for the driver assembly. The initial drawing was made without the light in hand…
For mine I just made the heat sink and added about a 1/4” thick plate on top of the emitter shelf to raise my reflectors up to meet the lens. I used 4 Winnie reflectors with 9V MT-G2 emitters.
Richard said that with all of the XM-L’s replaced using XHP-50’s it got stupid hot in seconds, couldn’t really run it 30 seconds before the heat sink. After the heat sink it would run til the cells died. I was very pleased with that, especially considering he measured 39,000 lumens. 
Funny how much the GT4 tracks that thermal design with the heat sink in place… being integral the fins are much deeper and much more effective, can’t wait to see the GT4 in action! 
What! ? ! ? ! … GT4 listed on Amazon? … 
.
I think you mean the GT mini?
Some sort of April 1 joke…maybe?
Maybe justanotherguy….
I think TA overlooked this part of the link…
- /LUMINTOP-GT-4- 4119-Edition / …
I’m dying for some details on the GT4. TA let’s see some beamshots from your prototype lol