I can't facepalm hard enough.
Okay. I'll try to explain this for you, but realistically you need to do a bunch of research on battery safety/ohm's law before you even think about picking up a mech mod (let alone rebuilding/firing coils for one).
Your Sony VTC5 battery is "rated" at 3.7V. This is sort of the "average nominal voltage" of your battery. At full charge, your battery will be outputting 4.2V (not accounting for voltage drop through the mod). As the battery is drained, that nominal voltage goes down, and less voltage is applied to your atomizer.
In a mech mod you need to understand what voltage your battery may be at, as you run the risk of over-draining and permanently damaging your battery if you go too far below 3.3V. Some people prefer to charge their batteries lower, but for the purpose of longevity and general safety, I like to not let my batteries drain much lower than 3.6V.
On a regulated mod, the chip in the device is outputting whatever voltage/wattage you tell the device to output (within the limits of the chip, obviously). Theoretically (and this depends on the resistance of your coils too), if you set your regulated mod to 4.2V, you will see the exact same performance that you would out of a mech mod with a freshly charged battery. The only difference, of course, being that the regulated mod will continually attain that voltage by stepping up/bucking down the battery's nominal voltage, whereas a mech mod will drop off from that initial 4.2V as the battery is drained.
Mech mods, about 2 years ago, were literally the only way to chuck clouds (or get any sort of formidable cloud, let alone a huge plume of vapor) as all the regulated devices on the market had extremely low amp limits. Sub-ohm used to only be possible on mech mods, since there were no regulated devices on the market capable of firing sub-ohm coils. Nowadays, there are regulated devices capable of outputting craaaaazy wattages/voltages. These triple-battery parallel boxes (while excessive, imo) are capable of pushing out as much as SIXTY AMPS. Just so you understand, 60A would be like 1800W to a .5 ohm coil. Needless to say, nuts.
My main point is this: You can simulate a mech mod on a regulated mod (by setting the output voltage to 4.2V) with your .5 ohm coil. You cannot simulate a regulated mod on a mech mod (as the mech mod's voltage = whatever the battery's voltage). For this reason, you've taken a step backwards in terms of convenience by going from a regulated mod to a mech mod. In regards to your specific build, a .5 ohm build may be PERFECT when applied the correct amount of wattage/voltage, but on a mech mod you're only able to apply whatever the battery is outputting, which in this case (I'm guessing) it's just not enough. You can try less wraps (meaning lower resistance) or a thinner wire. Ultimately, I strongly vote that you stick with the regulated devices for now.
And just some video evidence to prove you can indeed chuck clouds with a box mod, this is .5 ohms at 6V:
The same coil on a mech mod takes forever to heat up, and barely produces any vapor even after the ramp-up time.
