Lumintop GT4

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. :slight_smile:

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… :wink:

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,

I’m in the True Heart of Texas… about 45 miles East of the exact center of the State. Or on the I-35 corridor between Austin and Waco. :wink:

Edit: Well dang! My memory really is rotten! I’m about 103 miles East of the Geographic Center of Texas, which is way out around Rochelle. :wink:

Been enjoying the free A/C and low electricity bills here recently though

The good news is that the R90C goes on sale a lot now for barely $200 since it’s been out a while. I hope we see some great comparisons soon using the two monster lumen throwers, and not just hand-picked GT4 prototypes…after the comparison I believe the only question will be…now should I wait for the V2 of the R90C!

Agreed. I just wish both the R90c and the MF04 weren’t so short. I can’t stand the look of a massive sized head matched with a short tube. Therefore if the output is nearly the same I would always go with the lumintop version. I don’t know why it irks me so much but it really does.

Same reason I insisted on the longer tube from the start. They kept wanting to make it short for reasons I could never understand.