Resistance - Voltage query?

[Semi Reduction]

Howdy peoples!
I'm a newbie to the world of mods, and just received a S/H GGTS.
Anyway, I found a graph posted here on ECF a while back with recommendations for matching resistance to the voltage of the desired battery/s. I've noticed that a lot of people use 1.5ohm LR atties on 3.7v batts. The graph (linked below) states that 3.5v is about as high as one wants to go coupled with a 1.5ohm atty, I know that's not much of a difference to 3.7v, but with a freshly charged 18650 that's omitting 4.2v, is that an overload as the graph states, or is the graph a little off the mark?

http://www.e-cigarette-forum.com/fo...el-power-worksheet-voltage-vs-resistance.html

 

[Slurp812]

if you have a VV device, I have a simple way to get nice and close to 8.0 watts. just add 2 to the ohms for the voltage. A bit less for the higher ohms/volts. Like so: 1.7 ohm 3.7 volts. 3.0 ohms 4.9 volts...