OH HELL YA, Definitely Tom! I will PM you!
I don't know about going from xhp35 HI to sft40, but xpl-hi to sft40 and even more so CULPM1 to sft40, i notice that the sft40 is larger (especially than other 4040 footprint emitters), and that the centering rings need to be adjusted / made larger to fit the sft40. Sounds like that fact worked out perfectly in this case :))
Would 4 or even 8 18650’s in parallel not be too much for the SFT40?
Maybe, yes, needs to be checked. I'll probably use 35E's since I got a lot of them, but still from previous testing, the 35E's do almost as good as 30Q's in many cases. Suppose the limit is about 10 amps - don't want to exceed that. Unfortunately, all my carriers are modded for max amps for the SBT90.2's, so maybe need to take off the bypasses, and of course, use thin LED wires. Will have to find a way of measuring the amps from the carrier as well - not sure I've done that before.
Modded carrier, I've posted details before I assume:
I have been seeing more and more batteires like this on 18650batterystore recently, Tom.
I wonder if they would help in this situation? a 6amp battery. Also, i believe Samsung has a 5amp 18650 too.
BatteryMooch has been testing BAK by the way - New Chinese manufacturer that has been testing well in the 1-2 he has done so far!
yup, not in stock, but here it is
Half BAK'ed amps, interesting... Yea, they would probably work, as long as the resistance is as high as the rated discharge amps is low. There's even a spec sheet for them.
The 32E would probably be ok as well - I know I got a couple, not sure how many.
BAK batteries are very good for the price and usually have more than the rated capacity. I pass by their factory on the way to the beach.
The 3350 mAh 10A look good for $4, but sold out.
Too bad I can't get a 9-10 amp regulated driver to fit this thing that can run A2.
Once the attiny1616’s DAC is supported in Anduril2 we can make low components count linear drivers that will be fairly easy to design boards for. Slap in one or two super SO8 FET and a very low resistance current sense resistor for super low dropout voltage (as close to direct drive as possible) if you’re okay giving up some dimming range (which is probably fine on a big thrower like this).
Wow, that would be great!!
I don't even know what you said here, but it's exciting! Lol. And yea I'll sacrifice lower range anyday on a large thrower for regulated top end and no fear of burning out my led.
this may be a dumb question- but here it goes. I thought I have seen you "piggyback" a driver before. If I'm not mistaken, you strip away components from the original driver, and then run leads to a new, smaller driver that has the regulation/UI/etc that you need for the light, and solely keep the original driver "shell" / pcb for its size and fitment.
I imagine you need space in the head to do this, but could something like this be done with say the noctigon K1 driver? Or better yet, a kr4 9amp A2 driver? Because it's cheaper to buy. Because that'd be awesome.
A 9A K1 driver piggy backed actually sounds like a great idea. Would still recommend low amp cells to keep the heat down since you lose your thermal path doing this
Even then unless you add some thermal compound, maybe silicone potting to increase thermal dissipation to the original driver/host I think the piggybacked linear driver will step down too fast, before the host is hot, depending on the output level.
See this graph with an SST-40 and 50mΩ of non driver stuff (springs, wires, cell), which is kind of a high number for four cells in parallel, even if they really low CDR.
2~3W is a lot for a board without thermal path to the host.
Hhmm, I got some high amp lights piggybacked. I always run 2-4 jumpers for ground to the piggybacked driver though - I'm thinking it helps, never proven though. Dunno - on some stock drivers, there isn't a whole of contact surface to the shell, so I' not sure the way I piggyback is much worse.
Here's an Amutorch X9, triple XHP50.2 3V hand burner" that I measured 30.7 amps with a GOLISI 26650, about 10,000 lumens at start:
With a couple other hand burners (
):
Ah yes but with DD FET there is not a lot of heat generated on the driver, just from the FET Rdson, traces, and 7135.
For a linear driver with the DAC, something like this :
.
Maybe with 0805 instead of 0603, and bigger case for the opamp, since the board is so big 
Dang, that's nice!
Damn, you guys are good haha. Very interesting stuff! Freeman- did you just design a BLF GT 3 volt board for this ??? Lol.
Yeah, but it didn’t take me too long, I just placed the components quickly, it’s pretty easy since there is a lot of space, I used 46mm but I’m not even sure what the actual size is ?
Something even better would be a buck driver, especially since the original carrier is 4S ? For high efficiency and full current for the whole battery range, but that’s more complicated of course.