Nope. Pretty much all (if not ALL) 18650's are gonna be rated at 3.7 volts. Full charged they'll be 4.1-4.2 volts and you don't wanna get them lower than 3.5 volts. The difference between the Efest and Sony is that the Efest have a 10 amp rating and the Sony's have a 30 amp rating. Sony's are great if you wanna run anything lower (like I do). I variate between .3 and .4 ish with all the different dual coil builds I do and ALWAYS run those 30A Sony batteries with them.
If you struggle with the math, there's lots of ohms law calculators online. If you input your voltage and resistance it'll tell you your current (amps) and power (watts). I downloaded an app for my phone that I use ALL the time.
