As long as I’ve been around this has been the holy grail of drivers, a true 17 mm 5A buck driver. Let us know if you find one.
I can think of at least 2 high ranking BLFers that tried to make one from scratch, and failed.
There are rankings? 
There are titles, why not rankings?
LD-40 : LD-40! (17mm Buck driver, 3-16.8v!)
post#103
(3xR200 stacked on top of R100:
Input: 2 × 18650
Output: ~4.72 A)
There were some posts in that thread about stacking sense resistors to get more current so go ahead and try it. Apparently it generates modes by pwming a fixed current the same way a 105C does but probably at a lower frequency since medium generates whine. I’d love to hear about a bit more usage of this one even though it doesn’t have a programmable mcu.
I saw the LD40, but the low current doesn’t help me. I have a HD2010 with an extension and a UF-1405. I’d like to put a XP-G2 in each and drive them pretty hard but I have no real options.
But you can resistor mod it for upwards of 4A…?
It has pwm flicker and whine but better than the nothingelsethatsizeavailable.
I’m going to try to figure out some type of adapter to make a 20mm work. These lights are useless to me until I can figure out a way to do this.
Try 3/4” copper pipe with a copper shim inside and press fit it on the outside of the driver part of the pill if you have space. That’s what I do for uniquefire 1405’s.
Make a BLF driver and then put an in-line 5amp resistor on the way to the emitter?
i didn’t think the BLF drivers would handle 2x 18650’s in series
The BLF drivers will handle a whole lot more than that. I drove a 3x MT-G2 with one. I melted the wires right off of one and put the wires back on and it still worked fine that was with 3x32650. I used them to drive single MT-G2’s with 2x26650’s and they work great. The problem is that they are direct drive on high so you would kill a single XM-L2 but I wonder if would be possible to place a resistor after the driver and before the emitter? I haven’t tried this but it seems like it would work. You know, one of the little round ceramic ones with the color coded bands around them.
I could be way off on this, so maybe somebody with a little more expertise could tell you if it will work or not. I know it would work in a direct drive setup I just don’t know what it would do to the driver. The modes might not work right or maybe not at all.
I do know the BLF driver works great with MT-G2’s and with multi-emitters. So even if it won’t work for a single XP or XML you could consider one of these.
hmm, guess i was thinking about something else. I think by putting in an inline resistor, it would constantly change the current. It wouldn’t keep it at just X amps. If it was getting say 10a on DD and the resistor decreased it to 5 amps, then as the battery drained it would lower it to 4a, then 3a, then 2a, etc. It wouldn’t let it stay at 5a until the battery could no longer support it.
I am after throw. Unfortunately, I won’t get that with the mtg2 or the xhp50 or 70.
Have you seen what Richard posted today
He is releasing soon 2 17mm buck drivers one 3A and one up to 8A (only 6A to a XM-L2 class emitter) that has the option to use either a bigger SMD inductor on a daughter board or a toroidal inductor.
I guess it is in part because he uses the smaller attiny13a-mmu, to be able fit more/better components to make it possible.
Not being an EE I can’t say for sure whether the resistor would work or not. My first thought was no since the resistance load in lower modes would result in a different voltage drop (V=IxR) than in high mode but the low modes are just pwm pulses of the high mode so maybe it would work. Be dammed inefficient though with so much surplus voltage being converted to heat. Way back in the dim and distant past I ran a 78L05 modded AK47 with the 7135’s soldered to a copper ground sink and put that in line with a 7W 1 ohm resistor and ran it at 12V into 3 XML’s. Worked fine, the resistor got hot and the 7135’s didn’t. Then I removed the resistor and it still worked fine but the 7135’s definitely got hot.
i just checked it out. It’s be awesome if he can make it happen.
Yeah, fingers crossed 
but i am not worried, i am sure it will come eventually, if he can imagine it he can probably do it 