The There Are No Stupid Questions Thread

I still think your numbers are low. ~20A in 6V XHP70.2 should be getting close to 7000 lumens, especially on a cold start. There are losses for “OTF lumens” but I wouldn’t expect it to be over 15%

According to who? Why do you think this?

I think most OTF losses are between 25 and 35 percent.

You should ask TA. He tested these same lights so he has a good database.

Maybe it is related to the Lumen Tube diameter? I have the small Tube. If I had a bigger diameter maybe the higher output lights would read differently? Maybe Maukka needs a higher output calibration light to sell?

All the professionals use large integrating spheres. This is the standard. There could be flaws in the idea of using a Lumen Tube. Maybe the use of 3 diffussion sheets is too many or not enough? Maybe the beam shape does influence the output? IDK. The tubes are way cheaper to build and seem to do a pretty good job.

I considered building a 1 meter sphere to test lights in, but it’s expensive, takes up a lot of space and I’m not that interested. I would not put all my faith in lumen numbers. Also, some people’s numbers I trust more than others. Amp draws are still a pretty good reference point in my opinion.

Considering all specifications & performance, which flashlight would you choose & why?

  • Lumintop GT Mini Pro XHP50.2 (1)
    * 3500 Lumens, 480m throw
    * 18350 or 18650 battery
    * NarsilM
    * Cost: $49.95
  • Lumintop FW21 Pro XHP50.2 (3)
    * 100000 Lumens, 325m throw
    * Anduril
    * 18650 or 21700 battery
    * Cost: $69.95

Choose what works best for your needs.

Neither. Not a fan of XHP50.2. It’s better suited to GT Mini, but I’ve disliked the GT Mini somewhat ever since it was released. It was a silly play off the BLF GT’s popularity, a poor man’s D1S, and not even an aesthetically pleasing light (to me).

But I see why it gets used. It’s the easiest way to put the biggest lumen numbers possible on a light. Just slap a FET and 3V XHP50.2 in everything. Nevermind the atrocious beam quality, floody nature, rapid temperature throttling, etc. It’s worse than when we started throwing SST-40s in lights and calling it a thrower LED. Like what? A domed 5050 LED? And then it was getting thrown behind FET drivers (because, again, cheap) where it’ll draw way more power than it needs to. The optimum was something like 6-7A and an efficient regulated driver around there would’ve been awesome.

Sorry for the rant. If you said I had to use it, I’d pick the GT Mini. The throw will be way more usable - the “325m” on the FW21 Pro is only at max lumens, which is only sustainable for like 5 seconds before your fingers blister. So you’d end up singeing your fingernails every time you needed to see the other side of a parking lot. But if you were going to force me to accept one as a gift, I’d say the FW21 Pro, so I could sell it.

Thank you! This is useful info. I’m not well schooled on the XHP50.2. I thought the beam pattern looked OK from photos & video, as well as the flood. But rapid temperature throttling was not covered in those. So this light essentially becomes a firecracker. It goes off. Loud bang of light, but then… it can’t handle it & must step down. So all that fanfare for nothing. I guess there’s a reason why something like the BLF GT90 has active cooling. The Mini has too focused a hotspot, while the Mini Pro looks a little better. But still… it pales in comparison to the big brother.

In terms of the size class I covered in the listing above, I’m thinking an Emisar D4SV2 would be a better candidate.

What LED emitter do you favor for a good combination of throw and spill? Are you a fan of the latest OSRAM emitters?

The D4Sv2 is really a top-tier 26650 light. Almost Q8 performance in a much smaller/lighter package, with plenty of emitter choices. Very practical balanced beam, with as much range as most people will ever need. That said, if it’s a dedicated thrower you want (like wanting to reach 250m+ for extended periods of time) I would suggest something else.

Depends what the size of the optics/reflector are and how many emitters the light has. LH351D is my current favorite 3V, 3.5mm footprint LED by a lot. It’s fairly floody (almost the same as XM-L2) in EDC-size lights though. High-CRI, decent or great tints if you buy the right bin, potential for easy dedoming/slicing to tighten the beam+warm the temp+make it rosier. I cut half the height of the dome off on all my stock or modded LH351D lights except the SC64 LE.

The new OSRAM emitters are great for getting max throw, but the beam will be significantly narrower than almost any other emitter, maybe save a dedomed XP-G2 or SST-20. I have a C8 with the 2mm^2 version and it’s a CANNON but not very practical inside 100m since the beam is so tight. Color temp choice is very limited if that’s a factor for you.

I can tell you misunderstood some of what scallywag wrote. You have to learn to seperate opinion from fact. Where he talks about beam quality, you read it as beam pattern. That is 2 different things. By quality he is probably refering to the color quality, which is not too good, but okay for most. Pattern is the physical shape and angle the light comes out.

I’m not sure what he means by it being floody. By using a bigger die led and small reflector the hot spot gets bigger. Your spill light is brighter as it’s directly related to lumens.

Short run time should be expected for all small lights that put out high lumens. I have not done any research into the FW21 Pro, but looking at its size and if it really does 10,000 lumen you can tell it will got hot very fast. This is the law of thermodynamics. So consider Turbo to only be a burst mode. Not something that can run for long. For something that can light up a football field and be so small its impressive. Not practical, but impressive.

Like I said earlier, you need to choose the light that best fits your needs.

GT90 does not have active cooling.

The GT Mini with xpl-hi has a die size of 1.9mm x 1.9mm. So that die size matched to that reflector gives a pretty small hot spot size and the spill light is a bit weak at 1200 or so lumen.

Then the GT Mini Pro has the equivalent of a 4 to 4.5mm square die (the dome adds effective area which is hard to calculate). It’s a pretty big jump in surface area like about 4 times bigger. Using the same size reflector, this causes the hot spot size to get larger and now the spill light goes from 1200 lumen to 3500 lumen. Your spill is lighting up things much more than the Mini.

So there are always pros and cons. For example, between the Mini and Mini Pro, do prefer the smaller hot spot or larger hot spot? With both lights set to 1200 lumen, both will last a few minutes. The Mini gives you much longer distances compared to the Pro as well as appears brighter simply because the smaller hot spot concentrates it’s 1200 lumen into a smaller area. The Pro spreads it’s 1200 lumen over a larger area, so it will appear dimmer. A tighter focus looks brighter because it increases “intensity”.

The Emisar D4Sv2 is a TIR style light, no reflector. It creates a noticeably different beam pattern. The hot spot tends to be a bit bigger and the spill light is noticably less. Keep this in mind concerning your usage needs.

For instance, I personally use my lights for walking at night and I prefer reflector based lights as I can shine the main beam forward and the spill light illuminates the ground in front of me. With TIR lights I find the ground is not illuminated well so I have to wave the light back and forth from straight ahead to down back and forth. It’s a bit annoying.

There is no such thing as a good combination of throw and spill. It all depends on what you think is good.

It seems you have narrowed down your choices to a size and ramping UI. All 3 lights are similar in size that are easy to carry and pocketable. Tell us what your other needs are. Do you need a certain distance? Or a certain run time at a certain distance? What are you using it to do? Are you picky about color temperature? Do you prefer NarsilM, Anduril or RampingIOS?

Sometimes you just have to buy a light and see how it works for you. If it’s perfect, good. If it’s not perfect, you find a light that corrects one of its flaws and see how that one works. After a while you see that certain designs fit certain situations.

Anyway, I hope that helps.

Yes, I tend to see “tint” as color quality, and beam would be the pattern (flood vs. spot, rings, artifacts, tint shift, etc.).

I have an FW3A and have to say, the runtime on turbo is really quite good. I get a good minute out of it before it starts getting too hot for comfort, then stepping down. Actually, it may step down earlier than that, but my eyes don’t see it. Seems to me like the FW21 Pro may be more of a “marketing gimmick,” like scallywag pointed out, easier to resell. It’s “sexy”, I must say. It’s not TIR, has reflectors, so it would throw more than an FW3A, but also delivers decent spill. I’ll have to read up more on the XHP50.2, though.

Yes, sorry I didn’t address that before. Hadn’t quite thought through my needs. There’s so many attractive flashlight choices, making it easy to end up with redundancy. I already have that!

What I’d like to have is a hand-held thrower with a really decent NW beam (4000k ~ 5000k) and also some decent spill. I do have a Zebralight SC64c LE with LH351D emitter. Terrific light. It sort of does what I described—good throw & spill. But, output is just barely over 800lm. I’d like to pump out closer to 3,000lm in a slightly larger form factor. I enjoy Anduril, which is partly what attracted me to the FW21 Pro.

I mentioned the Emisar D4Sv2 because of it’s massive wide hotspot. I sort of consider that “concentrated spill,” albeit more narrow than a wide reflector. And thermal management seems to be pretty decent. And of course, it’s a novelty with its aux LED’s and Anduril UI. But in essence it would be an “upgrade” to my FW3A. More novelty. Something for later on, though.

I use my larger lights for night walks & camping / lounging in forest / beach areas. The FW3A provided wonderful near field flooding. Not great on throw. To fill that niche, I have two Nitecore lights - EA4 (4xAA) and EC4GT (2x18650). They are both nice throwers, albeit averaging around 1,000lm. So while I’m pretty well set for smaller near field lights, I thought I might be able to find one that has both good throw & spill. Seems that’s the unicorn. I do wonder, if a light could mate both OSRAM & CREE (or Samsung) in one light to do both?

Yes, both you and scallywag have been helpful—thanks. So to get my thoughts in order here, I should back off on another near-field light. Already have enough filling up that slot (FW3A, Astrolux S43, RRT-01, H03 FC, and SC64c LE). I want a good handheld thrower (2x18650, 26650, or 21700) that can double the output of my Nitecore EC4GT with a very nice NW beam. Plus also good thermal management. If UI isn’t programmable, must start on low. And would be nice to have moonlight and hidden strobe. Doesn’t need to have built-in charging, but would be nice if larger cells than 18650. Lastly, would like to keep cost below $99 (like a discounted flashlight from a year or two ago), if possible. Are there any decent candidates for those loose reqs?

I can’t think of any lights that fit your need. When you talk about a handheld thrower I’m thinking of a light with a single LED and reflector. If you also want around 3000 lumen I typically think of an LED like the 50.2 or 70.2, but they are not the prettiest neutral White. The only powerful led I can think of that might be a nice looking NW is the SBT-90.2. Maybe an Astrolux FT03S, 4500lm, 5700K. Freeme has it for $90. You can look into that one.

Maybe someone can recommend something cheaper or better. I’m not real up to date on the latest flashlight models. (My everyday work lights use the 50.2 and 70.2)

Oh yeah, you might look at older xhp50 lights using boost drivers. This older led was pretty nice looking, color wise, but output was only 2500 lm or so with a boost driver.

If you’re looking for higher lumens in a thrower, I’d say to use the Astrolux FT03 as your starting point of reference. It’s available in the original SST-40, which won’t hit 3000 lumens, but out-throws the newer XHP50.2 version that does hit 3000 lumens. I think there’s also a version of it (FT03S?) that has SBT90.2.
The FT03 is, in my opinion, the next step up from “jacket-pocket” size (though it will surely fit in larger jacket pockets). This is mostly to do with head diameter. It takes a single 26650 or 21700 as you please. The official Astrolux specs are… well, Astrolux specs, so be sure to mentally adjust them down by a factor of something like 25%. Also, if you decide it’s a good form factor, please keep in mind that with A$trolux, you get what you pay for, and read up on the threads devoted to common issues with the light.
Frankly, your price range allows you to get something with better build quality, so I’d recommend the FT03 as a starting point for the research. If you think the head diameter is too large for what you’re interested in, you’ll have to start thinking really hard about the tradeoff between lumen output and throw.

I’m fully convinced that for a really decent long range thrower, you need a larger reflector. Unless you’re looking for a pencil beam. Living where I am, really no need for something as large as a GT90, but FT03 is more sensible. The drop-off from turbo is pretty steep & reviews are showing the head gets too hot to touch fairly quickly. I will be on the lookout for comparative reviews to see what else turns up.

Actually caught a LEP review by Matt Smith that looks seriously cool (Acebeam W30). Essentially a “white laser”. I think there’s HUGE potential for this. I can foresee having a multi-LED cluster of conventional emitters with a LEP in the center. If that LEP could be independently controlled, that would be really amazing. This way you get great spill & throw in one flashlight.

Matt Smith did a nice comparison of these lights. Here’s the video bookmarked at BLF GT Mini Pro:

BLF GT Mini Pro seems to output turbo longer than the FW21 Pro (video bookmark 7:24), while also producing noticeable throw. Beam quality looks pretty decent from his capture…

Personally I’d get a Kaidomain C8.2 w/XHP50.2 and be able to choose temp over a GT Mini Pro if I wanted that kind of beam profile and form factor.

Actually probably would choose a C8F over that too now that Sofirn offers them with 90CRI LH351D. Similar performance and light quality that’s better in almost every way (tint shift, CRI, etc.) + ramping UI (not as good as Narsil or Anduril but still good).

D4S is still king of the hill in this size/output/throw class though IMHO. With the floody optic or some diffusion film/DC Fix you still get generous spill and there is a ton of choice for emitters.

Only trouble with D4S and others in that form factor is the limited time on high. It doesn’t look like there’s much choice out there, without stepping into a much higher price bracket. Considering Sofirn, just checked out their SP70. Not an EDC with 2 cells in series but wow, does it give ample performance for the $$. Very nice beam profile. Two temperatures available. The UI is not bad either. A little strange, but without the programming options it’s simple enough to remember. It does have ramping mode. Unfortunately it has last mode memory, but you can override with moonlight or turbo, which helps mitigate that. Rumor has it Sofirn is planning a BLF edition, but nothing confirmed as yet. Might be a year or more out.

I’ve got a question about driving the 6V XHP50.2.

I’m planning to run four 6V XHP50.2 in parallel on a 5050 Q8 MCPCB with a direct drive TA driver. I have read that the XHP50.2 6V is sensitive to overcurrent and gets dark dies fast. To limit the current in direct drive I would not bypass the tail spring, use 22 AWG wire and use only 10 or 20A max discharge cells. They would run on two 26350, 18350 or 26650 batteries in a Haikelite SC04.

I would also cut some traces on the Q8 MCPCB and add some sense resistors. Do you think it is enough if I add one R010 resistor for all four leds or would it be better to have one resistor for each led?

I would use two 5000K 90CRI H2 and two 2700K 90CRI G2. I don’t know if they have a different Vf so maybe I should use one resistor for the 5000K and one for the 2700K? Before I start the build I’m seeking advice from anyone who has experience with the XHP50.2 6V so that my leds will survive and run safely in this flashlight.

Probably a couple of dumb questions: :slight_smile:

1) I already have an SST20 flashlight (Convoy S2+)
Is there any advantage getting a flashlight with SST40?

I was thinking of getting another budget thrower, I have a C8 XML,
but would prefer a side switch, or e-switch

2) Is this a legit store: Convoy Direct ?
https://www.aliexpress.com/store/3135023

I’m not sure I understand you. Four 6v in series needs 24v. You have a flashlight that runs on 24v?

SST-40 is just a bigger led so it has the potential for higher output. I know the FT03 is a great budget thrower using the SST-40. It will be brighter with more throw than both the lights you mention.

I dont know about that store. Why would you buy from them instead of from Convoy direct?