No. Some 18650 have higher energy density than any 26650. Higher capacity. So if you want to pack more power into the same space, using several cells, use 18650.
However, if you just want/need higher current from one cell or a few cells in series, and for some reason don't want to use 18650 in parallel, then 26650 are better.
The reasons for why this is so has been discussed earlier in this thread. The popularity of 18650 has meant that it has improved faster. That is the unique advantage of 18650. Using just physics 26650 should be better, but economics and investments in production gear and research are also involved here.
If improvements of 18650 slows down, 26650 most likely will catch up and pass 18650 regarding energy density, but that is not the case today. And then we have 32650. They have a similar advantage over 26650, but production volume is even lower.
Since the volume of one 26650 is close to double the volume of one 18650, it would be interesting to compare the current from one 26650 to two 18650 in parallel. I would expect that two 18650 in parallel would be able to deliver significantly more current than one 26650, and would also have significantly more capacity.
In the typical comparison between the capacity of 18650s and 26650s, one factor that is often ignored is the reliability of capacity measurements. And in this area, 26650s do comsiderably better. The common NCR18650B, for instance, is rated at 3400mAH. But that’s down to 2.5V. When you look at the capacity at more real-world termination voltages and current draws, capacity goes down to around 3100-3150mAH. By comparsion, a 4000mAH Kimg Kong ICR produces over 4200mAH under the same conditions. And even though a Keeppower 5200 doesn’t do auite as good as the King Kong, it still produces a respectable 5100mAH. And now we have the 5500mAH Soshines, which look like they also hit the numbers fairly well. So while it may not look like it on paper, 26650s are actually getting quite close to 18650s in terms of REAL WORLD capacity for their size.
It IS the case today. For the last 18 months (or so), 18650 capacity has gone nowhere. NOWHERE! The last improvement was the ‘3600mAH’ NCR18650G. But this was not much of an improvement over the NCR18650B (which has been around for close to three years). However, in the last year and a half, 26650s have shot up from 4000mAH (4200mAH, actually) King Kongs to 5200mAH Keeppowers. And now we have the 5500mAH Soshines. Granted, I don’t think energy density will exceed that of 18650s. I think cylindrical Li-Ion batteries have hit a wall as far as maximum capacity for the size. But unlike 18650s, 26650s (and 32650s) have room for growth.
But all across the board cells are now able to sustain the same currents at slightly higher voltages on load (5A for example), that is an improvement in the industry as currents are higher and higher. Cells in that matter are the NCR18650BD or BL and the LG MH1 of course.
Capacity means almost nothing and especially capacity tested at 1A load current.
That being said an example is the NCR18650A with 3100mAh, do I even care about it having higher capacity than the LG HE2 that I have with 2500mAh rating, because starting at 2A loads they are inferior cells, then we can go higher like 7-9A, the NCR18650A with it's 3100mAh capacity is literally nothing.
the 18650 is here and well developed aka “mature”
if any redesign of a product occurs that moves from the 18650 its going to flat lipo.
since the form of products is moving to thinner its the only way.
given a real need in a high volume product the 26650 will catch up as the big names put effort into them again.
I too fried the LED in my DD F13 with dedomed XML2. Had the basic mods, braided springs, 22ga wires, moved + to alternate location. Used 18650s with sleeve, was one of my favorite lights. Decided to up the game with some new 26650 Keepowers (~5200mAh) Died in less tha 5 seconds…
Have new FET 17mm driver and 20mm MCPCB with XML2 waiting to be installed…
theoretically 7200mah is possible.
the panasonic and sony 26650’s i have seen were optimized for power tools.
low i r rather than high capacity.
no real market for super high capacity 26650.
flashaholics and vapers dont count.
The 26650 batteries are several steps behind the 18650 and 21700. The performance of the best 26650 is comparable to that of an ordinary or mediocre 18650 or 21700.You can try with a Samsung 50S or 30T and tell us.
Man, old thread to dig up...again, apparently. That "batteryglobe" link is bogus...waste of bandwidth on the web. Those guys are regurgitating info that they don't really know, and the site is just another sham shell for amazon affiliate linking to make money on clicks and/or purchases.
26650 has come a long way, some pretty good cells available these days at least compared to what was available when this thread started in 2014 (or when whoever originally wrote that content on the affiliate website was aware...). I don't know if we'll ever see the same consistency and quality from most Chinese cells but they are certainly capable of better products these days and they are the ones who improved the 26650 since the major players never put any effort into it. The Queen Battery 26800 might be a great example of what is possible now...actually has given us the good combination of current capability and higher capacity rivaling some of what smaller cells developed into (I'm sure energy density is still somewhat less but I'll let someone else math that out...).
21700 sure became the new leader...hopefully that won't be going away anytime soon as EVs and e-bikes and such may move to larger cells.