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Lumintop GT94X Review: long-distance monster thrower
Lumintop GT94X specifications
|LED||4* Luminus SBT90.2|
|Beam intensity||2,175,000 cd / 2950 meters|
|Battery config.||4*21700 (optional 8* adapter)|
|Modes||Many (Uses NarsilM firmware)|
|Blinkies||Multiple (But hidden)|
|Reflector||Quad smooth reflector (4 in 1)|
|Review date||October 2021|
Okay, so you want a very powerful flashlight? Check. And you want to throw a beam almost 3 kilometers? Check. And you want it to use a carry handle? Check. And you want it to use a keychain ring? Uhmmm, no, sorry.
For many people, the GT94X is something from a science fiction movie. But for us, flashaholics, this is something we’re excited about and looking forward to playing with. The GT94x produces an enormous amount of lumens, in combination with a beam that reaches almost 3000 meters. The GT94x stands in a 4-year-old tradition. It all started with the incredibly famous Lumintop BLF GT. A flashlight that could reach 2,000 meters, with the weight of a newborn baby. Not really, but you get the point.
I’m not sure how many Lumintop GT series there were made, but I think I lost count. At least, this one is something I really liked to get and bought one as soon as it became available. It should be throwing farther than most other multi-emitter lights out there. I can’t wait to put it to the test. On paper, this should belong to the list: farthest throwing LED flashlights of the world.
It’s good to keep in mind, we’re not talking about an EDC light that comes with all sorts of accessories like a lanyard, keychain ring, pocket clip, magnetic tailcap, or holster. No, this is something you will be carrying around with a shoulder strap, or in a bag. Anyways, this is what you will get inside the box:
- The flashlight: Lumintop GT94x
- Battery adapter
- Strap attachment ring
- Carry handle
There were no extra accessories in the box. The flashlight with the attached handle and a manual, that’s all I got.
Flashlight in use
Carrying a flashlight that weighs 2.5 kilos (without batteries) can feel like you’re working out in the gym. Fortunately, Lumintop includes a carry handle, so your wrists don’t get as tired. Imagine holding a newborn for a couple of hours in 1 hand..
BTW. besides the weight, the battery tube has also increased in diameter, because instead of using 4*18650 batteries, it now uses 4*21700 batteries, to the battery tube diameter is also slightly larger.
There’s only 1 switch, and that’s located in the neck of the flashlight. Unfortunately, the switch is located at the bottom of the flashlight when you use the handle, and the handle itself doesn’t have a switch. The handle attaches to the body with 2 screws. The same (tripod) attachment points can be used to connect to a tripod (of course). That way you don’t have to worry about the weight, and the switch will be located at the top of the flashlight.
Even though the battery tube is a little wider, the style of knurling is still the same. This gives enough grip, but it definitely is front-heavy. There is a strap attachment point near the bezel and an attachment ring at the tail cap.
TIP: After some use, the tailcap is difficult to remove, so I’d recommend unscrewing the body from the flashlight instead of just the tailcap. That’s much easier.
Build Quality, and Warranty
Lumintop builds very interesting and high-quality flashlights. This doesn’t mean that they are always immaculate, but you can expect a good product built with high standards.
The GT94X is a large flashlight, and the threads were lubricated with a type of silicone gel. I’m still the guy that uses a much thicker lubrication, also known as silicone grease. At least, that’s what it says on the package. The 3 different parts (head, body, and tailcap) screw together nicely.
There’s a stainless steel attachment ring near the bezel, and one near the tail cap. The one at the tail cap has actually 2 rings, and the one at the front only 1. I’m not 100% sure why that is, but I guess they have a reason for that. My package didn’t include a strap or anything.
If you look at the anodization, there is no spot or blemish to be found. Neither on the flashlight nor on the handle. The heat fins are in the right spot. Right around the LED board, and driver board. This means that it can dissipate heat quickly, and with some airflow going, keep the temperature in check.
And in terms of warranty, Lumintop gives a limited lifetime warranty. Details can be seen on their website.
LED, Lens, Bezel, and Reflector
Everybody knows that high-power LED flashlights produce an immense amount of heat. And most flashaholics know that the SBT90.2 is one of the most powerful LEDs used in flashlights, which at the same time produce heat like no other. But the GT94x doesn’t just use 1 single SBT90.2, but 4. This means that the light will get very hot to the touch, but because of the built-in thermal regulation, doesn’t get as hot as some other lights. However, the same thermal regulation will be the reason for a drop in output once the flashlight reaches about 60 degrees celsius.
These 4 LEDs are sitting in a quad-reflector with a smooth finish. This kind of smooth finish helps the beam to throw as far as possible. It will throw much farther than an orange-peel reflector that spreads the light more sideways. Lumintop claims a maximum throw of 2950 meters, so we will be testing that later on in this review.
For smaller EDC flashlights it is not uncommon to have a stainless steel bezel, but flashlights the size of the GT94X surely don’t have one. The GT94X has an aluminum bezel, so be careful that you don’t drop it.
The beam pattern is the typical flower petal shape, but outdoors that is not really noticeable.
Testing it with my Opple Lightmaster 3, the following data showed:
This means about 5000K with a low CRI.
Dimensions and size comparison
- Length: 239 mm / 9.4 ”
- Head diameter: 134 mm / 5.27 ”
- Body diameter: 62.5 mm / 2.46 ”
- Tailcap diameter: 68.5 mm / 2.7 “
- Head: 2212 g / 78 oz.
- Empty: 2619 g / 92.4 oz.
- With batteries: 2895 g / 102.1 oz / 6.4 lb
High power flashlight comparison (and throwers)
Size compared to other long-distance throw flashlights
Comparison 1, compared to the Lumintop BLF GT90
Comparison 2, compared to the Astrolux MF04S
Driver & User Interface:
The Lumintop GT94X uses NarsilM v1.3, designed by BLF member TomE, and adapted by BLF member Texas_Ace. See more info on this firmware here: http://budgetlightforum.com/node/54635
When you increase brightness, the end of the ramp is not Turbo. The end of the ramp I will call “High mode”. You can only activate Turbo with a double click.
Keep in mind that you probably have to set the Max temperature before doing anything else. The default max temperature is probably set wrong. Mine was set at about 30 degrees… I assume.
- By default, it has a smooth ramping menu.
- You can change this, in the firmware, to 12 other mode sets (see firmware explantion)
- For all other mode sets, I refer to the link above.
Default mode: FROM OFF:
- Press and hold: Low
- Single-click: to last used brightness setting, mode memory
- Double click: Turbo
- Triple-click: Battery voltage check
- 4 clicks: Lock Out mode, repeat to unlock.
- 5 clicks: Momentary On mode for signaling (unscrew battery to go back to normal settings)
- Press and hold: Smoothly ramp up and down
- Single-click: Off
- Double click: Turbo
- Triple-click: Battery voltage check
- 4 clicks: Lock Out mode, repeat to unlock
- 5 clicks: Momentary On mode
LOW BATTERY WARNING:
- According to the manual it does blink when it reaches 3V.
- Since this is an enthusiast’s light, you have to ‘calibrate’ the temperature by entering the Configuration setting. (Press and hold the switch for 10+ seconds.. the light will ramp up… and then waits.. after 10+ seconds the light will start flashing, notifying you are in the configuration mode.
Then, at the 3rd option (you can count the second number of blinks after all the flashes) you click twice to select Temperature**. The light will ramp up to the max by itself, and you just wait until the light (point your infrared thermometer / thermal image camera at the hottest spot on the light) reaches the desired temperature. Then click the switch 1 time to set/memorize that temperature as Max.
- Yes, the Lumintop GT94X has a special Lock-out mode. You can get there from Off position by doing 4 rapid clicks.
- Nothing that I could notice by eye, which is what counts.
FIRMWARE / UI CONCLUSION:
If you don’t play with the switch too much, you’ll be fine. Just use the ramping mode, Turbo, and Low, and that is good enough for this type of light! The Momentary ON is also pretty cool though, in case you need to do some morse coding… or annoy your neighbors. For all the other customizable settings I would refer to the manual if you can understand it. It’s not easy to understand the first time though, good luck.
There are also multiple other features within NarsilM you can activate and deactivate.
- Moon mode
- Multiple strobe modes: 18 Hz strobe, police strobe, 2 sec beacon, 10 sec beacon etc.
- Timed or thermal stepdown can be set, and also disabled altogether.
Please see the following (dated) file for the NarsilM firmware manual. As far as I know, this is still the same as with v1.3
Batteries & Charging
Its predecessor, the Lumintop GT94 uses 8*18650 batteries by default and has an option 4*18650 adapter. The GT94X uses 4*21700 by default, and an 8* battery tube is optional. You can imagine that 8 batteries would be preferred, especially considering the large current it pulls. But considering the price of just the extra tube and carriers, I just ordered the standard GT94X anyway.
In the listing, they hint at a maximum current of 28A.. That’s insane, and I’m pretty sure I’m not able to measure that reliably.
There’s no built-in charging, so you also have to have a dedicated 21700 battery charger that can fit 21700 button tops. Because of the battery carriers, you can’t use flat tops. You have to add a solder blob onto the positive terminal of your batteries or remove the plastic washer on the battery carrier to get rid of this mechanical reverse polarity protection. I’d recommend doing the former. This is safer and won’t void your warranty in case something goes wrong.
Even unprotected button tops are a tight fit, so no, don’t even think about protected 21700’s. No way!
This is the gear I used for testing:
|Gear||Purpose||Link to buy|
|Hagner E4-X||Measuring beam intensity (throw)||Inquire at Hagner.se|
|Extech SDL400||Lumens and logging runtimes||Amazon.com, Amazon.co.uk,|
|Leica Disto D2||Distance for throw measurements||Amazon.com, Amazon.co.uk,|
|Uni-T UTi260B||Thermal camera||Amazon.com,|
All output numbers are relative to my homemade Integrating Sphere. It is set up with an Extech SDL400 Lux Meter for measurements including a Kenko PRO1D ND-16 filter. The base measurement is done with a Convoy S2+ that has been tested at 255 lumens.
For Amp readings, I use a Fluke 77III DMM. For higher amps, I now use a Fluke 325 True RMS clamp meter. For microamps, I use a cheap DMM with an easy-to-use micro amp setting.
The following readings are taken from 4 fully-charged Samsung 40T button top 21700 cells.
|Mode||Specs||start||30 sec.||10 min. (60 degrees)||10 min (no temp control)|
|Turbo||24,000 lm||23,902 lm||21,817 lm||365 lm||12,076 lm|
The lowest mode is the default lowest mode. In the stepped mode many you can tweak the firmware to make it even lower.
You can see the non-desirable output of 365 lumens after 10 minutes in Turbo (in reality within 5 minutes) running when set to the default setting, or even to 60 degrees. This means you can’t use this for search and rescue, since nobody searches for just 5 minutes.
High mode is better and still has 1700+ lumens after 10 minutes. Keep in mind this is not impressive when you compare it to some single-cell 21700 lights that can produce the same output.
This is the highest temperature I measured with the thermal controller disabled.
The runtime test was done with the 50cm integrating sphere, including the Kenko Pro1D ND-16 filter and Extech SDL400 data logging Lux Meter.
Turbo: a little strange behavior in my opinion. After the flashlight dropped in output, the remaining output was pretty low. After waiting 3 hours I thought the batteries were pretty low, but upon stopping the test, and checking the batteries, they were still 3.7V.. Hmm. I don’t think this is the correct behavior for a thermally regulated flashlight, and the flashlight cooled down to about 30 degrees. Update: this is actually how the firmware works. Thus, not the best choice for this kind of flashlight.
I talked with the other team members and decided to set the max temperature to 60 degrees. Unfortunately, this also resulted in the same behavior. After some minutes, the output decreased and ran at around a non-desirable, and non-impressive 365 lumens.
Keep in mind that this graph is not complete. The Turbo default and Turbo 60 degrees didn’t finish the runtime graph, because that was just ridiculous.
High mode was kind of okay, but definitely not impressive. It dropped to roughly 1700+ lumens and slowly decreased output till it reached 700 lumens after 2 hours and 40 minutes when it dropped to about 360 lumens.
My conclusion: get rid of Anduril and NarsilM in these big lights…
Sorry for ranting, but this has to stop in my opinion. I really don’t want to bash the makers of these firmwares, but rather the manufacturers that implement them? The makers spent a whole lot of time producing and fine-tuning these firmwares, but that doesn’t mean they are fit for all flashlights.
Measurements were taken outdoors at 20 meters with a professional Hagner E4-X Lux Meter (after 30 seconds).
|Turbo||2950 meters (2,225,000cd)||1,372,000 cd||2343 meters||2562||1.46|
My copy didn’t even come close to specs. It might be because of the 4*Samsung 40T batteries. Unfortunately, I don’t have any other high discharge button-top batteries. And to be fair, the output was actually spot on, so I don’t know why the beam intensity isn’t if the output is.
I retested it at 5 meters and got roughly the same intensity, so I’m pretty sure it wasn’t a measurement problem.
For the following beamshots, I used a Canon EOS 5D Mk2 and a 100mm lens. manual settings: ISO1600, .5sec , F4, 5000K
The first tower is 650 meters / 710 yards away, the second tower is about 450 meters / 492 yards away.
Disclaimer: I bought this flashlight with a reviewer’s discount, with my own money. Nobody paid me to review this flashlight, nor have I been holding back on problems or defects.
- 24,000 lumens at startup, and 21,000 after 30 seconds
- Impressive beam and a reach of over 2,300 meters at startup
- Looks like a monster
- Build quality looks good
- Comes with a carry handle
- Heavy at 2.9Kg / 6.4 lb
- Not reaching claimed beam intensity with 4*Samsung 40T
- UI: NarsilM doesn’t fit this light. Period. It drops output to 365 lumens within 5 minutes, and doesn’t increase brightness anymore.
- Default should have been 8*21700, and optional 4*21700
Explanation on star ratings:
1: Avoid: my phone flashlight would be a better choice – 2: Poor: significant defect or issues, much better options available at the same price – 3: Average: some defects or issues – 4: Good: recommended (minor issues) – 5: Great: highly recommended
2 stars: ★★
In my honest opinion, Lumintop should have built their own firmware specifically for this light, and not used an off-the-shelf open-source firmware like NarsilM. Even though the firmware is very cool and interesting on its own, it doesn’t fit this light at all! Every time Anduril or NarsilM is used in a flashlight, it performs worse than the mainstream brands, by default.
You can’t build a $650 flashlight that drops from 24,000 lumens to 365 lumens within 5 minutes and be taken seriously. 365 lumens is an output for an AA flashlight, and not for a 6lb heavy flashlight, with 4*SBT90.2 and 4*21700 batteries. C’mon man.
Fortunately, though, High mode is performing better, but still not impressive.