Honestly, think about it. If copper was so much more expensive and so much more difficult to machine, could we buy this light so cheaply?
Well, the copper A01 is $20 while the aluminum one is $9. So there is definitely a premium for copper, but not so much that it puts it out of reach.
If the heart of Texas wasnt so far from the UK i’d ask to buy one of these quad pill setups 
I wonder if with a small plastic cage around the copper head the light could be run indefinitely in turbo on an 18650.
The large chunk of copper with deeply inset heatsink grooves provides good surface area to emit heat. It’s polished and coated though. Could probably increase the emissivity by sanding off the outer layer and letting a nice dark patina take over. I suspect that even on turbo that chunk of copper will stabilize in temperature before the solder melts on the driver wires. And even better the anodized battery tube and battery tend to remain quite cool.
The only real problem is the copper gets too hot to touch. You can’t sink the heat by holding it in your hand like other lights because the copper gets too hot too fast. Perhaps all this is needed is something to keep the hand from making physical contact with the copper, while still having openings for air to circulate around the copper to remove the heat. A raised plastic or rubber cage could work.
I got my S41/Nichia a few days ago. I was not really impressed I’ve to admit! The few triples I built so far, mostly Nichia 219c, we’re all visibly brighter. All of them with the same A6 drivers. So what to do?
Today I simply did a complete light swap. I inserted a quad TPad with 4 XP-G3 S4 and a Carclo narrow quad optic.
NOW we are talking hotrod
I recommend also trying a reflow on the S41’s existing star. The optic it comes with actually has quite a nice beam pattern.
well - nichia 219b are not known for highest ouput 
I know they have other qualities, but despite that I was really a little disappointed. Compared to 219c side by side it’s like you miss the highest mode on your light
XP-G2’s of unknown (read:low-ish) bin and with their high voltage are not great either. My Manker E14 with XP-G2’s makes 1800lm while my warm white 219C triple does over 2000. Modded it will be!
Pure electrical grade copper (Cu-ETP, old name E-Cu57 or 58) has the best heat conductivity. Almost 400 W/(m*K). But it is a mess to machine.
If I wanted to make my life easier I would use a copper alloy (with Sn, Zn, Ni, Pb). Machining would be way easier but thermal conductivity may go down to 30 to 110. That is even worse that brass (120) or aluminium (75 to 236).
It will look like copper and it is heavy as copper. Maybe it has a different shine. I bet nobody will notice the difference.
Electric resistance will be different but it is difficult to measure.
Any news about the next batch of Nichia S41s for orders after May 25th? Will they ever be shipped?
My Nichia version shipped today as well. Now we wait… Again… Lol.
I was looking at the wires. Fairly thin silicone of unknown quality. I’ll bet if you upgraded the wires you would get an improvement. Even though I’m a modder, I’m totally happy with my XP-G2 S41. I know I could tweak it, but to my eyes it performs in every way I could want. I’m content and am going to leave it stock.
I can understand that, the output and beam is really nice, but I would need to know how a really good bin would perform, you may just get the same output for less heat and power.
And for me, I’m not so much into cooler leds, I bought the (cheaper) xpg2 version for modding in the first place
I was going to mention that if I ever picked up another, it would be for experimental reasons.
The efficiency does indeed drop above 350mA. Each mode above that is less efficient than the one below it, but it at least tries to get the most it can by keeping the 7135 chip on steady while the FET pulses.
Efficiency also drops in moon, making it the least-efficient mode. And it drops in the “low” mode too, though not nearly as much. At a very rough guess, I’d estimate the efficiency of the modes like this (ish):
- Moon: 30%
- Low: 90%
- Med1: 98%
- Med2: 95%
- High1: 90%
- High2: 85%
- Turbo: 80%
That is, if I assume that the 7135 chip by itself at full duty cycle is “100%”.
But I haven’t measured a S41 (don’t actually have one), and the numbers change anyway depending on the type of cell used and the voltage. And if the driver has a bleeder resistor, the moon/low/med1 modes get significantly less efficient. It’d probably be like 5, 60, and 90 for those. And all the numbers go down when the emitters are hot.
Anyway, a very rough guess but hopefully it at least illustrates the kind of efficiency curve it has.
I think the point of a multi-emitter 219B is that it gets a great tint with as much output as a single higher-powered Cree emitter. XP-L, for example. It’s the price we pay for high CRI.
The nicest tint I get on any light is actually from a triple 219B with a “moonlight special” 3-amp driver. It’s not exactly a hot rod, but it does give me 800 gorgeous lumens of the finest pure white. It’s what I use when I want to see what color something really is.
I wonder when we’ll have 92+ CRI 219C emitters in 5000K, and how bright they’ll be.
All well and good until you actually hold a 4258 lumen quad 219C X6 in your hand.
Or a 4634 lumen triple XM-L2 U4 1A X6.
Or a 5338 lumen triple XHP-50 SS/Cu X6. Or, with a pair of 18650’s, 7210 lumens.
Point is, sometimes it’s not about efficiency. Of either emitter or driver or cell or thermal transfer. Sometimes it’s just the pure joy of running it.
What TK was referring to above was simply that the A6 firmware, on level 3, is running the single 7135 chip at it’s most efficient output in a tested X6/X5 single emitter light. Most efficient for that particular light. For those that want to consider a long run time, like in camping or emergency use.
Like, Sure, my Corvette (hypothetical) has 600 HP but if I hypermile it I can get 31mpg. OR I can put the petal to the metal and laugh like a demonspawn.
Edit: By the way, the graph/chart shown above in Sharpie’s post is credit to djozz, he’s the one that worked that up and does enormous amounts of testing. Surprised you left that bit out, Sharpie.
Match did a lot of groundbreaking work as well, clearly the class leader in establishing the importance of copper under the emitter.
Here is just one of his threads on this subject with his accompanying charts.
Edit: Notice the number of reads at the bottom of that OP… over 37,000!
Match was pushing the limits, as was Scaru and a few other’s, like ChicagoX. Comfy started playing with the large 07N02 Mosfet, stripping a Qlite and force feeding the FET onto that board, all kinds of things started cracking open. MattAus drew up board designs, then Wight came in and started doing the same and WarHawk and several others busted it wide open with the MOSFET drivers. TK wrote new code and BAM! We were up and running in entirely new realms.
They’d design boards, I’d cram parts on em and stuff em in lights. Like I’ve said all along, I’m just the hack who cuts all resistance, I don’t design the stuff just make it scream in a flashlight. For me, it’s the build, which is why I’m going on 160 lights now. 2 or 3 close friends used to send me 4 or 5 lights at a time to modify, I don’t even know how many lights I’ve built, well over 300 for sure. Early on it was stacking chips, 12, 16, 20, 24 chips on a Qlite for power. Then the MOSFET’s killed that off almost completely and I learned to rewrite code in AVR Dude, flash the MCU’s and build my own drivers. The rest is history. I stuff these into everything, sometimes with 10mm drivers sometimes 22 or larger.
All along it was on the premise of Match’s charts, what can this take, what can I expect from that, and then the lightbox made it all real so I could see the changes being made, real fun there! I think Justin is the one that really got me started though, about 3 years ago, with his Scratch build contest. I managed to make a flashlight from a live .50BMG round and the door flew off the hinges, started cutting copper on my drill and rotary, no holds barred.
Gotta say, the little quads are great pocket dynamo’s, but really I’ve recently taken it too far… the triple XHP-50 is just too much for a smallish light, there’s so much heat generated even the full copper X6 pill can’t handle it. Not often I find a point that needs to be backed down from, but the SS/Cu X6 with 2 18650’s and 3 XHP-50’s is just excessive. Even more so than running an 18650 on this S41, I’m talking over 130 watts in a pocket sized light with a belt clip! Found the ceiling…
An 18650 in the S41 is capable of de-soldering leads. If the positive lead de-solders and touches ground, say with the light in a backpack and accidentally turned on, well, with luck the springs will collapse and break connection before anything starts arcing and spewing sparks and lithium. Perhaps the 18650 can be controlled when in hand, in use, but what if….