I actually used an online calculation that allowed plugging in the cylinder’s dimensions and gave a total volume. 
(Already knew I didn’t miss anything. 
)
Most of the time? Really? So 4500 mAh is not 50% more than 3000mAh? I have run lights on both the Golisi Gold 26650 and Samsung 30T 21700, I know what each actually gives to a light with high demands, and I’m familiar with how long each cell can run a 23,000 lumen light, so I really don’t see the theoretical point when I have actual results before me… I have the new HOhm Run 3000mAh 21700 arriving today, they claim a constant 39.5A and pulse 48A, so I will use it to feed a hungry emitter and see how it compares to the 30T and Golisi Gold. The CFT-90 can take it, regardless of what the cell can do, so it should prove interesting… (yes, I’ll also test the HOhm Run 21700 in said 23,000 lumen light and see what it’s 17 emitters have to say)