21700 doesn’t interest me. I invested in a bunch of 18650 cells already and they will last many years before failing.
So 21700 has more capacity…great but most current lights have inefficient drivers so I can stick with my 18650s and simply wait for better flashlights to get more runtime.
That’s been pretty much my same POV for a long while, but I do like, for example, the 21700 version of the C8F, because to use a high-draw cell in it properly, any 18650 would likely be 2800mAH at best, while the 21700 is almost double that.
And it just looks better, given the bigger head. An 18650 tube on a C8-type light just looks kinda skinny on it. At least the thicker tube from the 21700 gives it a bit more “balance”.
And I can always drop in an 18650 even without the sleeve.
I’m not sold on the copper head. I have the copper-titanium D4. It looks beautiful and feels great in the hand.
But it’s sooo heavy. I feel it bumping around in my pocket due to the weight. It’s heavy enough that it actually caused a pen I had in my pocket with the light and my keys to drill a hole through the bottom of my pocket. That doesn’t happen with ligher weight lights.
Hmm… I EDC a D4s, so the added width of a 26650 isn’t a big deal. But I really like the size of my EC65 and I wouldn’t mind more lights in that size.
The other issue is a lot of “tube” lights try to keep the reflector the same size as the battery tube so there isn’t a jarring transition (D1S). A 26650 light would allow a larger reflector resulting in more throw, but once again 21700 lights are slimmer and have I mentioned I really enjoy the size of my EC65?
Impossible to answer that question without all details.
I’m always looking for the ideal runtime vs output vs size ratio.
A light with big head I won’t even spend $1 on. (my 26650 light is more compact than many 18650’s)
Runtime is another big deal for me.
While nice lights (looked seriously at the 18650 version) it seems to be geared to much to a turbo monster which is of less intrest for me.