The There Are No Stupid Questions Thread

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?

JasonWW, Thanks for the suggestions, will check out FT03

That store is called Convoy Direct, that’s what’s confusing. I guess that means they are not .

I’m not aware of Simon opening a second store on Aliexpress. I would guess that it’s a competitor using a similar name to steal customers from the real store. It’s a common tactic.

Sorry for the confusion, I wanted to say in parallel. You are right, 24V in a flashlight makes no sense. Thank you for pointing out my mistake.

Okay, I see you want to use a SC04 light, now it makes sense. I never bothered experimenting with the 6v 50.2 with a FET driver because they always burned up as soon as they get power. Even from 18350 cells. If no one answers you here, try asking on this 50.2 thread. There’s a lot more folks who know about it’s limits. For sense resistors to handle so much power you’d probably need a bank of them. And they’d need to be big. I’ve never experimented in this area, sorry.

I wouldn't go that crazy with modding the driver or MCPCB. Keep the dual springs, don't use bypasses, use long thin LED wires. 24 or 26 AWG should do with some extra length. I'm not sure what amp level the LED's burn up at though - haven't had that problem, I assume there's been some LED testing to prove the burn out point?

I haven't heard of Vf varying with tint before. Sure, a 2700K will be a lower bin but the Vf? Never heard of that.

Of course I assume you are using a TA driver specifically designed for 6V LED's? That's a must. Plus you have to mod the carrier for 2Sx2P.

Thank you for the advice, JasonWW. I asked my question in the XHP50.2 thread.

I have sense resistors in the 2512 and 1206 sizes with 1 or 2W. Maybe the leds would survive if I add a R082 sense resistor to each of them. When I measured the tailcap current with two Liitokala 26650 and four Luxeon V2 it was around 9A on Turbo.

SST20 is a small, throwy LED available at 5000K and below, and in high CRI below 5000K. To my knowledge, the 70CRI versions out-throw XPL-HI despite being domed.
SST40 is a large LED capable of very high output (over 2000 lumens at like 6+ amps). It’s not available below 5000K nor in high CRI. It’s a floody LED due to its size, but gets used in throwers due to sheer output and compromise of lumens vs. throw.

Thank you, Tom E, good idea to use 24AWG wire.

Djozz tested the XHP50.2 up to 12A and it didn’t burn out. But once I read about a build with 7 XHP50.2 and two 26650 cells in direct drive where the XHP50.2 burned out one after another. So I’m concerned because it is said that the 6V XHP50.2 has weak internal connections and individual dies become dark easily.

I think with Cree leds the Vf is lower if they are 90CRI. I just assumed it would vary with the bin as well.

Currently, I want to mod the Haikelite SC04 whose reflector happens to fit a Q8 MCPCB perfectly. I have a TA driver with LDO and four Luxeon V2 wired 2S2P which work nicely. However, I want more power and a bigger hotspot. If it goes well, I might try it also for the Q8 with a 2S2P mod.

Ohhh, interesting bout the SC04, 2 cells config I'm sure. I've done the thin long wires in other lights to reduce amps - works well, and actually some stock FET based drivers simply use long twisty traces on the driver to result in the same thing.

This was an example from a 12X SRK. I bypassed the squiggles and got more amps:

I did not hear of a single successful use of 50.2 with FET driver. They all burned out. Some lights used really weak cells and lasted a couple months, but it eventually burned out as well.

This is why no one builds that combo.

Some leds work well with FETs and some don’t. I would ask around a lot more before committing very much money into the build.

The 3v versions are a different beast. They can handle FET drivers no problem. Of course using a single 26650 will reduce run times, but it might be better to just swap a new cell in than to have the 6v leds burn out.

Hey Jason, in expanding my search for a mid-sized thrower, I was gearing myself up for the Sofirn SP70, but then reconsidered the FT03 with SST-40. Seems that dedoming it produces a reasonable bump up in throw. Not as much spill as the SP70, and not same output level (XHP70.2), but coming in at half the price it looks pretty attractive. Have you dedomed many LED’s? I’m trying to figure out the best way to do it without having to remove the star.

Trying to dedome without removing the MCPCB from the light is asking for trouble. If your cutting angle is slightly off you’ll scrape phosphor from the emitter and end up with a blue LED instead of a throwier version of what you had.

Now is a great time to learn to solder, desoldering and resoldering wires to the star is incredibly easy. Matt Smith has great videos giving soldering/reflow tutorials:

The FT03 and SP70 are very different lights even though their throw distanceis about the same. The SP70 is like 6,000 lumen with a big hot spot and can light up a football field. The FT03 SST-40 is about 1,800 lm and has a much narrower beam. One is light and pocket sized (like jacket pocket) and the other is heavier and way too big for a pocket (I actually slip it in may back pocket with slacks). So it depends on your needs. Light up a football field or spotting smaller stuff at a distance. A bit like a shotgun compared to a rifle. Big wide beam of light or narrow and precise beam of light. Each beam size has their pros and cons.

I’ve only cut a couple domes. One was an old xhp70 just to see the change in hot spot size and throw, but I didn’t like the loss of lumens. One was a xhp50.2, but I didn’t like the tint shift. I dont really bother with slicing anymore.

You do have to remove the star. It’s a delicate process with a razor blade. I think the SST-40 needs to be sliced (some led models are chemically softened and lifted off).