I have a modified HX-1175b1 doing over 9amps @ the emitter 3S 32650,26700/26650 6v XHP-70.2 P2-1C in a T90-2 for 5500lm
Here is an old thread… Driver Info: HX-1175b & HX-1175B1 (Pic Heavy)
On the FX-30, if you changed the sense resistors from 0.041 to 0.029 (adding an R100) I think it was still buck, but just briefly. Any lower or with a wire across the resistors would make it direct drive (and possibly smoke).
Texas_Ace or someone could probably explain it more accurately. Assuming it was still running as a buck driver, it would fall out of regulation after a few minutes (assuming good high drain cells are used). What good is that? If you wanted a decent amount of regulated turbo time you’d need to lower the lumen levels.
Texas Ace was actually working on a buck driver for the xhp70.2 version of the GT, but gave up on it. That had more powerful batteries, 4 or 8 x 18650. With only 2 x 26650, the voltage sag is much greater on our light making a buck driver less effective at high output. I barely know the basics of buck driver design, so maybe someone can else explain it better.
That is using 3 batteries, while we are using 2. There is not much voltage overhead.
Kawi, you deleted?
Yea bridging the FX30 with solder would get like 9-10amps but then it may burn out after some time. It really depends on the components how long it last.
The issue is that when you increase current you need to increase voltage you can not do just one. So by increasing current to much say by bridging the resistors the voltage becomes unregulated thus making it a direct drive which is why it burns out. A buck driver regulates voltage.
A direct drive is easier and cheaper to make compared to a regulated driver.
You can buy regulated drivers that do high do high voltage and current but they are bigger then flashlight drivers but a company with resources may be able to shrink that design down or make one from scratch. If it worth it is another thing. If you can just make a regulated Fet driver cheaper and easier why would you bother?
9 Amps sound good for this kind of light to balance of heat, runtime and brightness …DD is too much IMO.
I think this name is great.
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People like either one of these for tube knurling it seems. The Q8 version or the SP33 version.
Most don’t care for the ‘flats’ it appears & most would like some type groove if possible.
Keep it simple
Not really. A better balance of heat, runtime and brightness is about 3500 lumen (5.3A)
I daily use my DD L6 at work. I just go to turbo and ramp down just a tiny bit. Like 1/2 a second. This gives me much less amperage, but it’s still plenty bright.
I just measured it and it’s at 3500 lumen (5.3A). So that is what I use nightly at work. On rare occasions I need more, so I hit the dbl clk. Bam, now I can see even farther.
So turbo is really just a burst mode. Temporary use for when you need it. (16+A)
High mode (5A or so) is what I’d like to see as the more practical use upper setting.
At 9A I was measuring 4500 lumen. 17A was 6000 lumen on my light. It may be possible to somehow limit the direct drive current on Turbo to around 9 amps, but I don’t really see the point in it. I’d rather it be 6000 or more. It would be the king of this style light. Skylumens L6 was 6500 lumen, but I think his lumen measurements are a bit exaggerated compared to mine.
If the SP70 came without bypassed springs, a less efficient FET and small led wires you might very well see 9A at most.
Shouldn’t you get more lumens at 17amps like 7500 lumens?
What is your tint?
4-5 Amp in Hi for practically use is fine but 9-10 Amp in Turbo for fun will be great without burning hot of DD 
It’s a P2 1A.
I’m sure some people might measure my light at 7500, but I measure 6000. I may need some fresh batteries. I’ve used mine a lot. They maybe be sagging in voltage more than normal.
Running the protected KeepPower 5200mAh will keep you limited to about 10 amp. It does on my light.
Kawiboy, i like your light with the head in the middle (S70s), with the smooth SS bezel (without crenelations, preferably Foybezeled ™), and the tube of the L6 on the Left, (and the sleeker tailcap) but it should not have the cutouts on the finning, (just round fins)
The tube in the middle with the rings are nice as well, but it should not have the ‘flats’
And and extra smooth ring, so you can choose whether to use the tactical ring or not.
just my humble opinion
EDIT
It needs to be heavy duty and classy as well
For the price/performance point of view :weary: no thanks.
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This is why my KeepPowers are tucked away in a drawer. Lol
We will see how many amps are pulled on the prototype. It might be 10, just like you want.
It also depends on the bin and tint which we have no clue of yet.
Yep I know, that is why I asked for a 3 cell tube. I wouldn’t want another 2S 26650 6v light, I have too many now. 2S 6v buck is useless, 2S buck is great for a 3v. Now a 3S 6v Buck current regulated @ 8-9 amps would be the only choice for me and there is nothing out there in a medium size light like the L6,X6 S70. Really a Linear like the LD-2 (not much better than a buck) or FET driver is your only choices out there now.
May be ask Sofirn to make short extension tube as accessory for that purpose , 3S form is too long for many user.
How many have you used? I have 5 of them, never really noticed the extra cell as being that Big of a deal 
and the 2x26650 as hard as I try, still will not fit in my pants or jacket pocket? And it would be more mobile then say the TR-J20 T90-2 or GT. There is plenty of 2S 26650’s out there already regardless of the UI and a 70.2 just saying…
I vote for 2 x 26650 with an optional extension tube (regarding the discussion above)
A buck driver will work but you will be limited to mere minutes of regulated runtime at 5000lumen+ output levels and a lower peak lumen level.
After that it will be a high resistance FET driver.
That said it will have a bit better battery life in the low modes, so it is a trade off that would need to be figured out.
Buck drivers with equal voltage LED setups have been underwhelming for me. Now a 3S buck driver could work very well but it would be hard to make a ~10A buck driver fit on a 30mm driver. That is why the L6 and S70 are limited to around 5-6A.