GT94 vs some of my other big lights

First post has been updated with the FF4 in 65watt mode.

The tree branch vs. the forest

Thank you for your informative beamshots. I have tried to take beamshots, but my attempts yield low quality pics. In a few days, when mine arrives, I will post my observations on GT94 vs X65 vs R90TS vs K75 vs MF05.

Very nice shots. I generally have seen less then a 10% improvement in throw with a SMO vs OP reflector. Many times less then that, a few more.

This is hardly noticeable to the human eye in most cases. The OP reflector does seem to remove the hint of a donut hole that the SMO GT94 had though.

Here are some thermal images I took of my light just to see how quickly and at what temp the GT94 steps down. I got 1min 54seconds before it stepped down.

Slightly above room temp as I had run it about 10-15 mins before.

30seconds on turbo

1min on turbo

Step down at 1:54 on turbo. I think 123F is a very conservative temperature.

Using a good camera with full manual controls certainly helps. I took these shots in a hurry so they are not as good as they can be but I’m using a Nikon Z6. Could have gotten even better pics but didn’t have the time. Can’t wait to see your output shots though, especially the one with the MF05!

Yeah I’m loving the beam as it is right now. I think I’m going to wait and see the results others get when they switch to the smooth reflector so I can decide if I want to swap mine out or leave it as it is. BTW is Neal going to be sending the smooth reflectors out on his own or are we going to have to email him and ask him for them?

Thank You ImagioX1 for the pics and info :+1:
I am trying to understand your last thermal picture.
Is the hot spot @ 123.2 deg the inner body of the head or the reflector ?
The reason I’m asking is that heat location is forward of the mcpcb.
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The thermal dissipation is so important, could someone shed some light on this pic ?
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To me it appears to be right at the base of the reflector where the LEDs would be.

As I posted above, the temperature calibration can vary by over 15c+ from the factory due to variances in the MCU. This means some lights will step down too soon and others will get too hot. This means that I have to bias the default setting on the colder side to account for the hot ones.

The setting for stepdown is 55c IIRC for this light but that can be as low as 40c or as high as 70c due to the variances.

It is always recommended that you re-calibrate the thermal control to your liking once you have the light. It can easily be done from the menu. You can then set it to whatever temperature you like or disable the thermal control all together.

That is right under where the MCPCB is, due to the taper of the metal under the mcpcb the heat seems to gets concentrated where it is stepping down due to less material for the heat to spread out to.

This is by design, the idea is to force the heat to move out the fins as much as possible. It seems to be working as the temperature in the center shaft drops rapidly as it moves down the taper.

Sadly the thermal camera can’t really get a reading on the fins since it only sees the edges of them where they are much cooler.

Thanks for the beamshots!

Thanks for the beamshots and the effort !

I only wonder if this still should be considered a flashlight ...... seems to be a bit of an "understatement" doesn't it ?

Thanks,

Martin

Its the weight of the GT94 that gets me. The size is not so bad. Its easily comparable to any of the standard 1million candle power halogen spotlights we used to have a few years back.

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So I just ran another test with my light. I ran it on high until low voltage protection kicked in. Now for the sake of clarity I had run the light a couple of times before I started this test so the batteries were drained just a bit. The light was still indicating 4 blinks and then 2 on the voltage readout but the batteries were not fully charged when the test was started. Anyway the light ran for almost exactly 25mins. I suspect if the batteries were fully charged it would have ran for about 30mins. Now take this with a grain of salt, but I did a ceiling bounce test right as low voltage cutoff kicked in and I got 4534 lumens. That number may be wildly inaccurate though. I dont have an accurate way to measure lumens so I would be interested in seeing what somebody else gets. Anyways here are the thermal images at 15mins and at low voltage cutoff.

15min

Low voltage cutoff

And the batteries immediately upon removing them from the light.

If the light max temp was only 125f, then that means you didn’t disable thermal protection correct? And you left the factory calibration?

You can of course re-calibrate it to whatever temp you want.

When I tested with thermal control disabled I was closer to 200f.

Note I said on high not turbo. And yes I disabled thermal protection. And the max temperature is displayed in the box at the upper left hand corner. It reached 130.6F.

No worries, some people say high and mean turbo so was just checking.

On high with stock thermal control that sounds like what I would expect. :+1:

Good to see the thermal path working as designed, only thing I would really do to improve it would be put some kind of insulator between the battery tube and the light engine to reduce temps on the grip.

I think thats really impressive. How the light is only warm, and you can easily hold it in your hand, and (if my numbers have any value) at lvc, its still brighter than a 40watt hid. For most of is runtime on high it was still considerably brighter than the FF4 is at 65watts which is rated at 6500lumens. It was only around the last 5mins or so where the brightness dropped down to lower than that of the FF4.

I see why you asked me this now. Something was wrong with one of my battery cells that was causing the light to not run at full power. So I redid the test after remedying that battery problem. Also during the test I did a ceiling bounce test to see how that GT94 actually stacks up against my other lights and these are the results.

Thrunite TN32 - 27 lux
Thrunite TC20 - 38 lux
Tractor Supply Hid - 42 lux
Dual 100watt halogen spotlight - 66 lux
Thrunite TN42 - 68 lux
Firefoxes FF4S 65 watt HID - 82 lux
BLF GT94 Turbo - 364 lux
BLF GT94 High 10min 158 lux
BLF GT94 High 15min 142 lux

And the temperature. I ran the light on high to show that turbo is not even necessary for it to beat HID and its quite able to maintain its brightness without overheating. And this is a passively cooled light.

@ ~5min. 2 min on turbo before switching to high.

@ ~10min

@ ~15min

So after 15 mins on high in a room with the temp at 75F the light was still ~173% brighter than the FF4 is at 65watts, and I was still able to reach down and pick the light up and carry it by the battery tube. Admittedly it was a starting to get a little uncomfortable after a few minutes of holding it but the light is meant to be carried by the carry handle which was still rather cool.

Ah, those results are more like what I was expecting with thermal control disabled. Very nice!