Here's the specs on the coil you're looking at:
Code:
Resistance 0.253 Ω
... per unit length 2.31 Ω/m
TCR in vaping range 879 ×10-6
TC precision 223
Heat flux per Watt 0.90 mW/mm²
Heat capacity 235.36 mJ/K
Current per Volt 3.95 A
Power dissipated 100.00 %
Width 1.35 mm
Thickness 0.57 mm
Length 109.90 mm
Surface area 1108.90 mm²
Cross section area 0.34 mm²
Volume 58.84 mm³
Mass 470.72 mg
Density 8.00 g/ccm
Here is
where those come from.
You can run 0.25 Ω on a single cell 18650. The voltage drop though will be quick. You will need to recharge more often. I have tried 0.25 Ω myself and did not enjoy having to recharge as often, or the heat from the vapor. When you run something like that you are going to be pushing the batteries. The more batteries get pushed the more the risks increase that something adverse, possibly dangerous might happen.
So yes, you can technically do this if you so desire. From my perspective it seems a bit unsound to follow that path. I like keeping batteries safe.
@casketweaver 's example above presents a very thoroughly researched and balanced approach to a build set up, he's also using a bit of a bigger formed battery capable of pushing what he has balanced. Note too his coils are simple built coils, nothing fancy just straight single strands of wire.
I've tried dual coils on an 18650 and found they end being too much mass, too much for the battery to push. Yes, in some regards if I built better that might not be the case. Ultimately though in my humbled opinion I do not see it so much as a builder's skill influencing mass. There's only so much skill going to offset so much mass and then reality sets in and you're still facing that mass. Facts don't change merely because you might be good at making pretty designs, no, facts stay facts. Mass also stays mass.
And a fact I see here is if you push batteries you improve risks that something you may not desire will happen. To me it isn't worth playing around to possibly get a venting or combusting battery. That's my opinion and only that ultimately, an opinion. Take or leave what you want, ymmv and all the standard disclaimers apply.
Oddly enough I know some that do run as low as 0.10 Ω on a single 18650. Not quite sure how they pull it off and suspect there is possibly some leg pulling going on too. Though there are a few who if they say they're capable I'm sure they've studied and found a slender means to be able to do it. I will not ask how they do it because for me it seems a pipe dream at best.