See post #19 in that thread. It’s the tallest item and is marked C102. It should be 1uF and I think that it’s a 5mm square inductor of about 3mm height. That makes it easy to pick out of the Coilcraft catalog if accurate.
Also note the huge cap, which is by no means the only high-spec cap on the PCB. I suspect that the board also sports two nice LFPAK33 mosfets but it’s difficult to guess very much from these pics.
My mistake, and tanks for the clarification. I ‘assumed’ it was higher voltage, because at the time it was the only 1 cell light using this emitter.
No problem. That LED is an interesting one because the SST90 and other products from Luminus are actually by far and away the highest current “3v” LEDs on the market. For a long time the SST90 was the biggest one, but Luminus eventually brought out slightly larger LEDs.
I’ve seen an SBT70 pull 17Amps through a single 18650 using one of Wights FET drivers. Lumens were a mere ~1500, but it sure gobbles up a 18650! (Eagle Eye X6)
Wonder about that Zebra light with the XHP-35 in it. EVEN I am aware of the simple fact that just because we can doesn’t mean we should. My ZL SC52 is making 1117 lumens, FET driver with TK’s ramping firmware, so why on earth would I want that big fat ZL with virtually the same lumens output?
Credit goes to ZL for thinking outside the box and making that XHP-35 12V emitter work on a single cell though. Pretty useless for me, but groundbreaking all the same.
Crazy. I wonder if Luminus will ever bounce back into the useful-to-us territory?
FWIW that “chubby” ZL might be able to output all 1117 lumens on a half-dead high-drain 18650. IIRC you keep your cells topped off, but for some users (eg myself) having the ability to get full brightness on a half-dead battery is appealing.
I’d definitely like to tear one apart just to see how it ticks.
Very excited for this, following. Would love an XHP50 or XHP70 in a 1” Convoy host as an alternative to triple XPL.
I’m trying to understand why the idea of a XHP-50/70 is so appealing in a small single cell flashlight? I’ve seen it said quite often lately “… as an alternative to a triple” but I don’t get the why part? The XHP-50/70 is a Quad on one substrate. The 50 is 4 XP-G2 and the 70 is 4 XP-L2 dies. So what is to be gained? It’s going to have to be floody due to the cross pattern between the dies, an orange peel reflector or an optic will have to be used, so in the end they look fairly similar in beam profile. A good triple or quad light does the same thing, makes similar or more power, so I’m confused.
Enlightenment? (yeah yeah yeah)
Aren’t the components required to make a good boost driver on the large side? Difficult to make a reliable boost driver in a small package? And then there’s extra heat from the driver itself, right? Wouldn’t it also put a beat down on a Li-ion cell? I really don’t know, that’s why I’m asking.
Well, the first thing that comes to my mind is a single, larger reflector versus 3 or 4 smaller TIR or reflectors for individual emitters. Even with the OP reflector, the throw distance should be considerably longer.
But, it seems that for most people it’s just a matter of being able to do it. It’s not for any practical reason. They just don’t want to be told that something can’t be done.
David, nice thought. BUT, the orange peel reflector needed to blend out the cross pattern will kill throw. 1120 lumens of orange peel large reflector as compared to 2700 lumens of triple small optics. I’ve built a few lights with the emitters in question, and yes, the 35 can be made to throw decently in a very large reflector. My main one is using 4 18500’s and making some 2100 lumens from a modified LD-2. But for a single cell small light, that’s not gonna happen. Especially with the 50 or 70, and we’re still talking about a 20-24mm reflector, orange peel. Floody (sure, not as floody as a 10507, but not throwy either). If the light can take a 65-80mm reflector, a single cell would be a strange set-up anyway. Even for me. lol
Hey, I’m all for the “don’t tell me what I can’t do” frame of thought. 
I think I see though what they’re getting at, they THINK it’s gonna be a thrower, in spite of the vastly larger die surface over the emitters used in real thrower lights. But still, wouldn’t it be really tough on a single cell to run boost like that?
Oh yeah, I’ve thought all about the different characteristics of electrical supply, demand, output, run-time and size, and compared to other emitters, and frankly, I can’t find an excuse to build a XHP-35 light at all. At least the XHP-50 has performance similar to a MT-G2 in a smaller footprint, so it should be thought of as a possible replacement for MT-G2 in lights where the size of a MTG or XHP would make some sense.
Honestly, the best place I can imagine to use a “single cell” boost driver for these emitters would be in a parallel multi-cell light, like a Courui D01. That way, ya don’t have to mod the battery tube to series config, but ya still get the run-time of multiple cells feeding the emitter. Some people might also find use for it in a single-cell light that has a throwy reflector for its size, like the LuckySun D80 or The Manker X6. Instead of having to somehow fit a couple 18350’s into the tube in order to run a XHP or MTG class emitter, they could use a boost driver (if a good one existed). One 18650 has around 50% more capacity than two 18350’s, so it would help run time. And 18650 is a more standard size, so they can use the same cell(s) in multiple different lights, instead of buying another size.
FWIW “big” boost drivers are a different ballgame from little ones. (30-50mm vs 15-17mm)
What about a good boost driver for a single cell L2 to run an MT-G2 or XHP-70? That would be cool. I know mine are 17mm drivers, but I think Simon is making a 21 or 22 mm… at any rate the area where the driver sits can easily be expanded from 17mm to the larger boost driver sizes.
I can see doing that, for sure, as I really like the L2 in single cell format. The big fat 26650 would vastly improve run time over the smaller cells with a 5200mAh being available. Again though, what kind of hit would the cell be taking? Does the boost circuit pull a high drain from the cell? Does the boost driver itself make a lot of heat in the conversion process?
Dangit! If someone shows me a really nice boost driver I’m gonna have to get another L2!
The DQG boost driver pulls something like 6 amps or more, to get a measly 1.5A output. Try for more output and the components on the input side of the driver catch on fire.
Yeah, I put a DQG driver in a Shadow JM26 and it gives sort of decent light through an XHP-70. Fairly weak by our standards though. Glad I didn’t try to bump it, not ready to do Bar-B-Q just yet.
Wow! Yikes! That’s terrible (lack of) efficiency! :SICK:
Not really. Efficiency relates to power (watts) - comfychair only mentioned current. For a hypothetical example: 6a * 3.5v = 19.2w while 1.5a * 10.5v = 15.75w. The example shows an efficiency over 80%.
Um…grains of salt and all that…
My DQG driver pulls 2.64A at the tail from a 26650 LiNiMnCo Powerizer. It pulls 1.52A at the emitter. Just got done checking it both ways. This is through the XHP-70 in a Shadow JM26.
I think it would be easier to just invent a new high voltage battery chemistry. (that should tell you how feasible the ‘small, high output boost driver’ concept is)
The boost driver thing with a single cell gets exponentially worse as input voltage drops. Lower B+ means higher current draw which equals even lower voltage which means even more current and it keeps getting worse and worse. It’s not that hard to get good numbers out of it with a hot, fully charged cell. Real-world use is where it tends to go to shit. If you had a non-battery power source with a constant, stable, predictable input voltage that let the input current stay in a safe range all the time it would be easy. But then it wouldn’t need to be sub-20mm, either. And also probably wouldn’t need to be a boost driver. Just use a supply voltage better suited to the load.
Now try it with a battery that’s down around 3.5-3.6 volts.
Yeah, except I was assuming a full cell to begin with, and the Vf of a XHP-70 wired in a ~6V configuration at 1.5A, which is only 5.9 volts for a total of ~8.85w! But if it’s pushing ~12v, then of course you’re right, it’s not that bad. 