A good VV is a cross between a mechanical and an EGO type battery. It's usually the "evolutionary step" beyond an ego type. They offer more power than what an EGO style battery can provide. If you asked me a few months earlier, I would say that the Variable Voltage (VV) or varialbe wattage (VW) devices wouldn't do sub ohms, but that has changed in the last few months. Again, using the
Ohms law calculator, you can plug in variables as you like. You only need two parts of the equasion, and it will calculate the other factors. For example, if you had a 3.7 volt ego with a 2.4 ohm coil, you'll see you're running roughly 5.7 watts at 1.5 amps.
A VV/VW device has this algorithm built in, and has a variable voltage/wattage regulator to supply that much power to your coils. These devices usually have their own wattage limits. for a while, the limit was 15 watts. The Vamo has that 15 watt limit, as well as a 5 amp limit. So, if you use the calculator linked above, you can plug in a few numbers and see, It's got a limit of 1.2 ohms, 15 watts, 6 volts, 5 amps. If you plugged a 1.2 ohm coil in, that's it's absolute lowest.
Now, all these numbers may not make much sense to you now, but with a little experimentation, you will see how it all comes together. I learned early on, that the coil reacts differently depending on how thick the wire is and how long the wire is. My normal was 32 gauge wire for a while. I used to rebuild my clearomizers by wrapping 32 gauge kanthal around 3mm silica. That usually gave me a 1.8 ohm coil and a decent vape. I used a vamo. I realized that at that setting, 10-12 watts was my sweet spot. I could replicate that with an ego twist type, since if you cranked the voltage up to 4.2 volts, it would provide the exact same vape. I could replicate that on a mechanical mod on a freshly charged battery, but when the battery starts going lower, the vape quality wasn't as good as the vamo. When I plugged in 3.7 volts into the calculator at 1.8 ohms, I noticed the wattage/amperage went down to 7.2. So, I came to the realization that I like 32 gauge wire at 10-12 watts.
Later, I bought a roll of 28 gauge kanthal and wrapped my 1.8 ohm coil on it. The wire was much thicker, and that made the coil almost twice as long. Running it at 10 watts wasn't poducing enough power to heat up alll that kanthal, so I had to up the wattage. Even at 15 watts, it still wasn't as good as the 32 gauge. So, my solution was to shorten the wire. I managed to shorten it as short as it could go on the vamo, which was enough to wrap a 1.2 ohm coil (the vamo's limit). The vape was much BETTER than the 32 gauge. IT had more vapor, and slightly warmer. I did have to up in the wattage to the 14-15 watt range, but it was good... batteries didn't last as long, but I had some ICR batteries that were rated at 7 amp limits.... which is more than the Vamo's 5 amp.
When I went into mechanical mods, I realized from the get go.... ICR batteries will not do for mechanical mods. IMR = safe chemistry, ICR = Unsafe chemistry, but usually had a longer "run time" known as MaH (Milliamp hours) With the IMR's now reaching the Milliamp hour ratings as the ICR, there's no need to play it un-safe. my ICR batteries are listed as 3100MaH, but they actually test at 2700MAH. The latest Sony VTC5 IMR batteries are rated at 2600MaH. So,t he option was a no brianer.. either continue to use the unsafe batteries, or go safe with the same run time. The Sony VTC 3, 4, 5 batteries are all rated for a 30 amp discharge. So, if I wanted to check the maximum rating I could do, I plug in 30 amp and 4.2 volts (on a fresh charge, that's what most lithiums put out) Theoretically, I could run at .14 ohm running 126 watts.... that is way too much, and I don't like pushing limits, but it did offer a wide range of options. I could use the 28 gauge setup at 1.2 ohms... but double the vapor if I wanted. When I tired that on an aqua, the coils heated up much faster and the vapor was much thicker and richer. two 1.2 ohm builds comes out to .6 ohm resistance for the atomizer. on a freshly charged battery running 4.2 volts, that puts it at almost 30 watts total battery output... (15 watts per coil) and is a 7 amp drain from the battery.. well within it's guidelines (VTC 4).
So, that just gives you a bit of what goes on behind the scenes of mechanical mods. It's a bit of math, a bit of tinkering, and a bit of experimentation to find out. But a variable voltage device did help me find a good basis on where to start off. With the current Variable voltage/wattage devices going up into the 50/100/150 watts, They'll offer as much or better performance than a mechanical mod. Vamo is a good starter and good priced.. it's what I started on. but it's limits are 15 watts. The IPV is another good one, offering 50 watts, but you have to unscrew the back to replace batteries.. which is not so convienent if you're "out and about". I'd personally stay away from the DNA type mods, since if you put the battery in backwards.. even just once for one second... you ruin the whole mod.
