Sounds like a 25W boost driver is good enough for a single-emitter light. Only 6€ more than a good FET+AMC driver doesn’t sound like much more expensive. So, it would be a $30 or $40 light, rather than a $20 or $30 light? Still a bargain compared to most boost-driven lights you can buy. Even if the price was $50 for a boost driver + a XHP50.2, that’s only half of what a similar Zebralight costs. Maybe the features or quality wouldn’t be as high, but BLF designs tend to be pretty good.
Area under the curve says H17F wins, but they both seem to end up at the same place, steady-state. (Physics).
Perhaps down to the slightly higher thermal mass of the Cu torch, but thermal mass is not the same as mass (though I do like a heavy Cu torch).
For an identically dimensioned torch, made of either Al or Cu, the Cu torch will weigh 8940/2712 = 3.3 times as much.
Whereas the Al has more than double the specific heat capacity of Cu (0.22 vs. 0.1) by mass, or 2.2/3.3 = 0.67 by volume, but half the thermal conductivity.
Which is why copper torches make little sense in engineering terms, over three times as heavy for marginal gains. They are shiney though and patinate nicely.
If you want thermal mass, with low actual mass, go Al, not Cu.
Get it right, and you’ll have better thermal conductivity too, with less mass.
Edit: small bits of copper used in the right place for thermal conductivity are excellent, MCPCBs and pills. But making a whole torch out of it is a bit silly. And kidding yourself that it adds “thermal mass” without a downside (actual mass) doesn’t fit the facts.
Brass of course is one of the worst possible things to use for removable pills, Convoy etc. please note. A proper integral Al shelf is far better.
Tom Tom: Not everyone is a ultralight enthusiast; sometimes volume is all that matters. Higher conductivity and heat capacity for the same size light is great. Were it not for the price and how much more usable aluminum is as a material, copper would be great.
Oh good, that means I’m not going crazy. I wrote EDN, then looked at your link and it was just Electronic Design. I edited my previous post lest anyone think I subscribed to Erectile Dysfunction magazine.
Not that there’s anything wrong with that for those that may be suffering………not that I would know about such an affliction but just trying to lend support to those who might be feeling a little less frivolous and………oh, god, there’s no way out of this, is there?
The results aren’t really comparable, since the H17F’s host had quite a bit more thermal mass than a D4. I’d have to measure them in the same host, or at least the same model, for comparable results. It might happen at some point, but that’s a lot of effort just to satisfy my curiosity about whether the H17F can adjust any faster or if what I saw was its fastest speed.
Hey don’t look backwards at what you are doing. Just drive forwards. Whilst understanding the back history.
I think there is a lot more to come with firmware/driver integration, but the driver hardware will have to become a lot better, not sure if this is understood, or whether anyone cares.
I don't see the reason why it couldn't have a nice boost driver. I can see a cheaper, not too-hot-on-high with PID being possible. The sc62w has it all on one board (with LED) with a $3 buck/boost driver from TI (although I read its fairly complex and 4 layered with copper core). I don't think that you have to make it super powerful for a smaller light. With scale it can drop it down. But the design of the firmware will be more difficult I believe.
This is the part from mouser: https://www.mouser.com/Texas-Instruments/Switching-Voltage-Regulators/TPS63030-Series/_/N-1z0zls6Z668jtZ1yyuq05
Still, making a small aluminum isn't impossible if you don't ask for too many lumens. I know this is BLF and we love lumens (my first loved light was the A6), but a small light like the D4 just cannot be used reasonably at its high. It burns paper. It dedomes itself. It can destroy itself from being used. I personally don't want that to happen, although I wouldn't mind more lumens on a thrower, I don't see the point of a flooder/muti much. A D4/SC6x sized light with side switch, nice buck boost driver (or even just boost), PID, killer interface with ramping, programmable modes or groups, some sort of low lumen modes, fits 18650, side switch and modability would be awesome.
I'm so excited that we are moving away from linear regulated drivers, then some into MOSFET, and now boost drivers all while getting smaller and smaller.
Thanks to this forum, there have been so many advances from the always draining incandescent, to the primitive strobing drivers with ugly tints, and now we have nice tints, way better interfaces, and are now even working on efficiency! Its so exciting!