As has been mentioned, you don't
need to go mech to squonk. But if you
do choose to go mech, here's a brief crash-course. I'll assume you're already familiar with coil-building in general but if not, maybe get your feet wet building for a regulated device before moving on to mech mods. Otherwise, here goes:
First things first,
always test the resistance (ohms) of your atomizer on a regulated device or stand-alone ohm-reader BEFORE firing it on a mech mod. Test it fully assembled with the coil and top-cap installed. Ideally, you'll want to do any dry-firing (before you install the wick) and "break in" the coil (after wick/juice is applied) on a regulated device, then make sure everything's tight and tidy (the coil might shift, and post screws can become loosened, when heat is first applied), and test again. Most mech mod battery incidents occur, not because of a build that's too low in and of itself, but because of a short-circuit that bypasses the coil or part of the coil entirely. Testing an atomizer prior to installing it on a mech helps to identify and avoid shorts against the atomizer base, coil posts, or top cap.
**[EDIT]
Special note on pinless or "hybrid" devices (although that is often a misnomer these days; "true" hybrids are a different breed of mech mod, entirely): Just don't use 'em, I say. These devices just add one more layer of "s**t that could go seriously wrong" for little or no added benefit. If you do decide to use one, make sure you know what you are in for. They are only compatible with atomizers that have a
significantly protruding, fixed center pin at the 510 connector, never with a flush or recessed center pin. A flush or recessed pin means that the outer threads of the atomizer connector -- which become negatively charged when the fire button is depressed -- will be in contact with the positive pole of the battery, creating an instant hard-short the moment you hit that button. Don't use them with factory coil heads, which can have soft, rubber insulators. Don't use them with flush or recessed center-pin atomizers. Don't use them with adjustable-pin atomizers, that might become flush or recessed during use. And please don't use them near me.**
Your battery is at 4.2 volts (it's not, really, at least not after the first few seconds, but we always pretend it's at full charge, for safety reasons.) The coil will draw current (amps) from the battery at a rate of:
AMPS = VOLTS / OHMS (Remember that "volts" is always 4.2 in our calculations.)
Your battery has a max amp limit, called the "CDR" (continuous discharge rating). Many batteries are advertised with inflated ratings, or with no rating stated. Check
@Mooch's blog for his latest charts and test results, for a more accurate CDR rating for a specific cell. There is a trade-off between amp rating and capacity -- batteries capable of sustaining higher amp draws will have lower overall capacities, and vice-versa. To select a battery, first determine what your amp draw will be, then choose a battery with the highest capacity (mAh - milliamp hours) that still meets or exceeds your needed amperage, and buy it from a trusted source (there's a list of vendors on the battery chart) to avoid fakes and re-wraps. Sony VTC5 is rated 20 amps (at 2000 mAh), while the Samsung 30Q is rated at only 15 amps but has a higher (3000 mAh) capacity.
If you'll note the amps calculation I mentioned above, you'll see that the amp draw is actually
higher the lower your build (ohms) is. So the 30q is not recommended unless your build is especially
high, not low. Higher ohms is always "safer" on a mech mod. It's when you start going lower ohms that the batteries start struggling to keep up.
Some people choose to leave a little "headroom" between their amp usage and the battery's max amp limit, sometimes as much as 50%. Others hold the position that the definition of CDR means it is a rate that is chosen to ensure good battery performance over
hundreds of cycles under
continuous discharge conditions and, as such, already has a significant "safety" margin built right in. Where you draw the line is up to personal preference.
Some grade-school algebra tells us we can rearrange the Ohm's law equation up above to read:
OHMS = VOLTS / AMPS
By plugging in 4.2 for the volts, and your battery's CDR for the amps, you can find the
lowest safe ohm level for a particular cell. For your selected cells, that gives us:
VTC5: 4.2 / 20 = 0.21 ohms
30Q: 4.2 / 15 = 0.28 ohms
Note that these are
minimum values, with no "headroom" left over. If your builds are this low you
will be "pushing the envelope" of safety. Depending on your vaping style, you can probably find a satisfying experience at twice, or even four times these levels which would, in turn, require only half or one-quarter of the amperage from your battery. Be smart, be aware. Keep your head on your shoulders (both figuratively and literally), we don't want to read about you on the news. Good luck and enjoy!
