1A discharge till 2.6V on a genuine IMAX B6 (on my Uni T UT-58E it is actually closer to 2.7V when it terminates, the B6 has non-precision resistors, well documented case in RC). Edit, when it terminates, the voltage is 2.8V under load on the UT-58E.
You can't calculate the proportion like this. When comparing sizes of the cells (thus, the "mass" of electrolyte inside) you have to take into account cross section area or whole volume.
The cross section of 18650: 3.14*r^2=254mm2
and for 26650 we have: 3.14*r^2=531mm2
(I'm neglecting the insulation and case thickness).
From these rough calculations, it seems that 26650 has twice the volume (therefore ~twice the electrolyte) of 18650 cell. If it was the same technology as in Panasonic NCR, these cells should have ~6000mAh. ;)
Not bad? It got 4526mAh from the first cycle and it actually surpassed their rated capacity of 4000mAh @ 1A. Most of the 18650 cannot surpass their rated capacity, even when they do, it's 20mA, So the King Kong got with 13% more than rated, and the NCR18650A with 0.6% more than rated. And I doubt all NCR18650A will exceed their rated capacity.
I wonder what capacity will the King Kong give at 4A (1C).
Mitro said that his MNKE 26650 got over 4000mAh even @ 3A discharge, and since they are IMR, probably delivering high currents is not a problem.
I mean not bad comparing their sizes against the Panasonic NCR18650A.
Let's see their volume differences.
Where the 18650 is roughly like this:
V= 3.14x81x65= 16532.1mm³
And the 26650 would be:
V=3.14x169x65=34492.9mm³
So,
3100--------16532.1
x------------34492.9
This gives us the 26650 should be 6467mAh which is much more than 4525mAh, so that is why I said it is not bad for a battery which is not as standard as a 18650 made by a company with a bigger R&D dept.
I am talking about the money spent vs what you get. Discussing the volume is something theoretical and you have to choose the best from what you are being offered now.
The 2600 Sanyo ( 2400+mah reality) seems to be the standard not the 3100 from Panasonic. Let's say that 2500mah is ordinary and the King Kong are ordinary 26650.
The price relationship is quite good, and I got 26650s from MNKE and I am happy with them,but my point was just regarding their sizes nothing else than that.
I would love there were a model from panasonic with the same Watts per volume in a 26650 version, so I cannot compare equal to equal, just the best I know of each model.