Nothing wrong with diving in and learning as you go. Gives me a chance to learn with you. Your buck concept is definitely worth exploring and I hope it can eventually be brought to reality.
I certainly appreciate all the stuff you’ve been up here to TA. The hobby has already benefited greatly from your contributions. Sure hoping Tom E adds the third channel to his FW. I have lots of momentary lights that I would like put your latest DD driver in.
Yeah, I am not giving up on it entirely, just going to finish up some other projects first before I dive into this one. I can live without an XHP35 SRK for a little longer….I really can….
I see china lights with what looks like super simple buck drivers in SRK and even when modded to 15A+ they still work fine, so I know it is not impossible by any means, Just something that would take more time and prototypes then I can afford right now. At $15 a prototype it could get expensive since it is unlikely that the first try would nail it according to RMM.
Thanks for the kind words, I have got a lot out of this site so I figured the least I could do is be open source with some driver designs. I am just glad that others find them useful.
If anyone can think of another size for the TA driver series please do let me know, in that thread naturally.
Because of the prior conversation regarding XHP-35 emitters, I thought I’d add this…
This afternoon I modified an LD-2 driver and put it in a Convoy L2 with 2 cell tube, 4 of the 26350 half cells to an XHP-35 E4 1D emitter on a Cutter 20mm star stacked on a second copper star. Results? The L-2 XHP-35 E4 1D, 3.13A at 2942.85 lumens with the half cells at 4.21V!
That’s the most amps and most lumens I’ve seen one make! New PB! Where’s my Gold Medal? 
Seriously though, it’s quite intense and it’s not even an HI, dome on HD. 170.25Kcd for some 824M throw. Learn something new every day… forget several old things in a matter of minutes so it’s a backwards curve. 
Edit: In retrospect the dome on is probably why it’s making 2900 lumens, all my other built lights using the XHP-35 are HI variants.
Very interesting, although this makes a lot more sense based on what cree rates them. This is right in line with what I expected them to make actually.
That said you might be onto something on the Dome possibly being to blame. Although it is the same bin it is possible that it still produced more lumens. Odd it is this much more though.
Has anyone ever tried a V2 XP-L dome on vs a hi version to see if they line up lumen wise? I think they would as my HI’s line up with ~28% loss in lumens you would expect vs the HD (in fact less then that in some cases).
Remember that in the XP-L, Cree automatically deducts in the binning for the lumens losses… Hence an XP-L V6 becomes an XP-L HI V2. 
Edit: It’s in that range anyway. I can remember building an FET X6 with XM-L2 U4 1C that made 1811 lumens, de-domed it and saw some 1500 and ugly tint. So I pulled the de-domed and went full dome again for max power. So they’ll all lose some lumens and take a tint hit when losing the dome.
They do this for the XHP35 as well, officially in the data sheet the HI version only exists up to D2 or D4 bin vs the HD E4.
Are there some F4 bin HD XHP35’s floating around by chance?
It is rather strange that the ratings would be this far off. I might just have to risk an LED, maybe just test it to the official rating of 1.05 amps to see what it does.
Well I am not sure what to make of it. I just tested a 3c E4 XHP35 HI and it made ~1900 lumens @ 2 amps and was not gaining a lot with more current. I am guessing that it would have maxed out around 2300-2400 @ 2.75 amps or so.
The odd part is it took twice the current to reach the rated lumens. That is not like Cree, they are usually very close to spec.
On the plus side it is still almost twice the lumens of an XP-L HI and should net similar throw figures.
I need to order an HD version to test side by side.
I put an HI variant in my MaxToch Shooter 2X and it didn’t quite match throw numbers but of course it’s making a lot more lumens so it’s all good. Had to machine a 2x battery extension tube so as a 4x 18650 it looks somewhat funky, but boy does it work well! lol
Will be trying one soon in an L6, probably shave the HD dome off…
At the very least the XHP35 is the brightest “single die” LED we have that doesn’t have issue with donut holes and can net some pretty good throw figures too boot.
If only it was a 3V setup.
I’d be happy if it had a 6v setup… I’m not sure why they couldn’t do the same as the others; maybe the XP footprint didn’t have room for separate pads?
If we get a smooth reflector for the L6, I just might have to buy 4 26350’s like Dale and do it anyways
Dale, did you get yours from Banggood? The generic purple ones? If so, how are they?
Yeah PD, they’re kind of a light lavender, marked as 2000mAh.
I haven’t tried a direct FET driver on one yet to see what it delivers in comparison to other cells but need to do that. I got 10 of em, figured I’d find uses for em all pretty quick and wish I’d gotten more. lol
I CAN say that the L6 with an L2 single cell tube and 2 of these is a sweet combo! 
An Ultimate test…
I have a TangsFire TS2010 with SBT-70 and an FET driver. The 4000mAh gold King Kong does 6.71A (rested, probably not a full charge) One of these little 26350’s will do 6.98A! Top dog cells allow considerably more of course, but they’re not too shabby.
Edit: The King Kong cell is at 4.12V while the 26350 is at 4.19V. Still…
Edit II: 4.40A to an XP-L in a F-13 with Bistro X6 driver, same cell.
That is quite impressive for the size. Glad I grabbed a couple. I tried the L6+single cell tube the other day and agree it is an interesting size light and amazing performance for the size.
Hmm now I need to figure out what little 26650 light I want to put an MTG in…. An L2 with MTG would be sweet…. but I already have one and I never buy two of the same light.
TA they fit in your L2 tube lengthwise? I know Dale already bored his out
Yep, worked great, stubby XHP70 light. It would make one heck of a “surprise light” in this small package.
Reminds me, I still need to mod the S70 and L6. Might also see if I can find a good High CRI replacement LED as well.
My S70 was one of the easiest mods I’ve ever done. Shave the LED, bridge a resistor, done. Instant monster.
Technically my L2 host is still empty, but it’s getting an XP-L HI.
This might be an excuse to get another Convoy X3 (I sold my other one), but they don’t like long batteries…
The L6 works with em, the L2 does not. It’s the L2 tail cap that I added depth to for the longer 26700 cell to work in. The L6 tail cap is a wee bit longer, it looks almost exactly the same but it’s very minutely different. Threads on ok though.
Yeah, the S70/L6 are almost too easy to mod for me, I don’t feel like I have “earned” the performance lol
I really want to find a nice high CRI XHP70 to put in one of them.
Cutter was the only place I found the high CRI XHP-70, I put one in my Olight SR90 Intimidator that they said was 96 CRI. I lost some lumens, but it’s a great tint and I like it a lot. I’ve got the battery tube reworked to house a pair of 32650’s so it’s got tremendous run time over the factory set-up.
Edit: If memory serves… I was getting like 6400 lumens on the top tier binned XHP-70 I first went with, the High CRI is making ~5600.
This project is officially back on now that I have the Texas Avengers basically finished.
See the op for where things stand now.