SOLD! NOW:
If the blf gt70.2 can push 7.5k-8k lumens, am I wrong in multiplying this by 4 and thinking this has the possibility to push 28k-32k lumens?
New to this. Just trying to learn as much as possible.
well in theory maybe yes, since this light will have no active cooling i think going over 20k is not needed imo. Better if they keep around that mark and make it run as stable as they can before thermal stuff does the job and steps down, but this is just me guessing unless lumintop wanna compete with acebeam and imalent in lumens war… Just looking at the few images posted i can imagine even at 20k lumens or so it will be an impressive light with 4 deep reflectors pushing what 1km throw or something ?
How are you going to limit the current of a FET driver?
Unless the driver is a buck+FET driver, you won’t be getting less than 20k lumens in this light, personally knowing it’s going to be in the real of 28k lumens+ instead.
Indeed, with 8x18650s and dual silver plated BeCu springs in the carriers, and a thick short dual silver plated dual BeCu springs, current is going to go amok.
Kinda sorta. You never get exactly 4x the output due to resistance and other factors but yes, it is safe to say I am being conservative in my 20k+ lumen estimate.
You can limit output on an FET driver by simply limiting the max PWM. The efficiency difference is surprisingly small vs a buck driver at high PWM levels.
OR, use lesser cells to limit output… like a Panasonic B vs a Samsung 30Q. Availability of amperage will be a deciding factor to a degree, setting PWM values lower will take it further.
In my own experience heat at the emitter shelf will be a deciding factor when utilizing multiple 70.2 emitters, while a single 70.2 can indeed be run pretty hard the accumulated heat of multiples tends to knock out individual dies in the 4 die array causing failure. This light is designed to handle quite a lot of heat, remains to be seen if all 4 emitters can handle the output of quality cells over extended times of full Turbo operation.
In my own builds I have found it can be exasperating having these die failures, losing one, two, then all 4 dies and having to replace the big emitters. So yes, I am very interested in seeing how this goes… given I can even afford this light I will plan to find out for myself how it performs. I DO like how it’s made and give Kudo’s to Lumintop for their efforts. 
I don’t think this light will suffer too much from heat build up in the head. The mcpcb is the largest I think that has ever been used in a flashlight and the surface area on the head is amazing as well.
I bet the surface area per LED is pretty close to the GT70 for it’s single LED.
Running 8 quality cells into the ground on a 96 degree night will surely tell a story… 
lol, very true, it will of course overheat in that case if thermal control is turned off. Although I am interested in trying this myself once the replacement LED’s come in. The GT70 peaked around 90-95c, I am not sure what the GT4 will peak at.
So… What I am hearing is in theory this should whoop the R90c in lumens output and be comparable in throw?
Absolutely, especially since the R90C is overrated quite a bit in terms of lumen output.
If I remember,the formula is C/5=(F-32)/9=>C/5=(96-32)/9=>
C/5=64/9=>C=5.64/9=>C=35,5°C.
If it so,I think that it is a very hot night…
I honestly would love this light with the emitters swapped out to MTG2’s, and if I had any issues with the 70.2’s I would be inclined to replace them thus. The MTG2 can still produce a nice beam profile in a good reflector cup and I really like the tint from the larger emitter. Yes, there would be some output loss, I would be okay with that at this power level. Cree’s big die is really tough as well, proven out time and again.
Love the extensive application of cooling fins here, very reminiscient of my now ancient SR90 Intimidator.
Now to find the funds in time for actual release… sigh… always something.
Indeed Theodore, hot humid nights are the norm in Texas for more of the year than many people care for. Rough on equipment almost as much as people.
A few days ago I was literally about a minute away from ordering the R90c. I happened to be watching reviews on the R90c and in the comments someone mentioned the gt4. So now I’m here waiting impatiently lol.
Is it as bad as Singapore? Or worse?
I like it as well,so,if they can deliver it by priority direct mail,I could buy it also.If they can’t,I try through Neal,who can deliver by this mail.
We can have 8 to 9 months of “summer”, with sometimes 100 days or more (consecutive, no mercy!) over 100 degrees F. Nights are hot and muggy, no place to not have air conditioning for sure unless you just love sweating in your sleep.
On July 23 of 2018 this mercury thermometer on our porch, in the shade, was reading a solid 120F…
My Turnigy laser thermometer, pointed at the grey asphalt of our driveway, showed 154F on the driveway. Gotta wear shoes! Nights, after days like this, can be pretty brutal.
Where in the heart of Texas are you at? I am east Texas 15 miles east of Houston. . . It’s true, our seasons are summer, summer, summer,