The other issue that you have to take in account, is the time it will take to get hot enough to produce the vapor. I have done so far 3 attys and have failed on that. Last one took about 3 seconds to heat enough to produce the vapor at 2.5v. I am working on the 4th I hope to lower the time to less than a second. I really need it to work that fast at 2.5v.