The T-Priv is a regulated mod, a completely different beast compared to a Mechanical/Unregulated where with a mech the amp draw formula is the Ohm's Law formula of 'Fresh Charge Voltage (Liion batteries this is 4.2v)/Resistance (Ohm's) = Maximum Amps', a regulated mod, the formula is from Ohm's Law but we term it "Watts Law" 'Watts Set/Lowest Battery Voltage/Mod Control Board Efficiency = Maximum Amps', the T-Priv is also a 'Series Battery Configuration', which gives Voltage X Number of Batteries, Mah and Amps of a Single Battery.
The Variables of the Formula are pretty simple to figure out, Liion Batteries Optimal Operating Voltages are 2.5v absolute lowest before they become damaged internally due to lack of proper voltage, though for safety concerns 2.8 to 3.0v we suggest as absolute lowest to run them down to, fresh charge the maximum is 4.2v. So taking 3.0v as example, being series we get 3.0v X 2 Batteries for your mod = 6.0v lowest voltage before a check battery error or complete mod shutdown (this is a hard limit programmed into the control board). Mod control board efficiency rating, you have to look the specs up on your particular mod, but the averages 75 to 97%, most mods it is safe to assume 90%. So a pair of examples, 100watts Set/6.0v lowest voltage/90%=18.5185amps, 120watts/6.0v/90%=22.2222amps, up the cutoff voltage to 3.2v per battery (or 6.4v lowest) we get, 100watts Set/6.4v/90%=17.3611amps, 120watts set/6.4v/90%=20.8333amps. Roughly if you use LG HB6 1500mah 30amp CDR batteries you'd cap out at about 180watts maximum, the 220watts on a dual battery mod are a hyped sales gimmick, if you are going to be running a TFV12 on the mod your max watts limits will be 20amp batteries 120watts max, 25amp batteries like the Sony VTC5A you'll cap out at about 150watts, 30amp batteries like the LG HB Series batteries you'll max out at 180watts (*Note - There are no 18650 batteries with a Continuous Discharge Rating over 30amp CDR like the HB2, HB4, and HB6 by LG, any battery that says 35 or ever 40amps maximum on their wrapper is the short 1/2 second Pulse Discharge Rating and a lie, always use the battery CDR, and only 4 manufacturers actually make 18650 batteries LG, Samsung, Sony, and Panasonic/Sanyo, most other battery brands are re-wraps, stay with the Big 4 brands). *Link in my signature has a post I break a lot of this down in more depth, suggest you peruse over it at your leisure.
Couple bookmarks to add
The Battery Mooch (Mooch has tested batteries a long time before he began vaping, he has an entire blog dedicated to battery tests and info), found here ->
https://www.e-cigarette-forum.com/forum/blogs/mooch.256958/
Steam Engine, this site has a lot of good vaping calculators and such, if you are going to be building your own coils the coil simulator will be especially handy ->
http://www.steam-engine.org/
Liionwholesale's Regulated Mod Amp Calculator ->
https://liionwholesale.com/pages/regulated-mod-calculator
Resistance with a regulated mod only applies majorly in these two instances, 1) mod reads the ohms of the coils, if the ohms are within the hard programmed safety limits of the control board, if below the lowest limit, kick atomizer error refuse to fire, otherwise 2) store the reading in memory, check what the watts are set to, calculate and adjust the voltage needed to reach set watts, after that, Ohms play no major impact on a regulated mod. Will the T-Priv safely fire the 0.15ohm TFV12 coil, yes as the safety range on the T-Priv is 0.10 ohms lowest in standard variable wattage mode to about 3.0ohms maximum, if the ohms drop below that 0.10 hard limit it will refuse to fire and kick a short or check atomizer error.
