Oh man, now you want to rope me into ECig convos? Dude this is going to turn into gibberish for most people really fast. LMK if you have questions. I've been a member of the e-cig community since before there were mods...back when r/electronic_cigarette was like 1000 people lol. Wanted to quit cigs. I've bought, designed, and used equipment from the first generations of products. My first hand made box-mod ran on 2 14500s, a small fet, and that's it. VERY rudimentary. It has come SUCH a long way even in the past few years. I'm currently using SS316L Stainless for my heater wire, hand wrapped 10/9 dual 26g 3.0mm coils running in TCR mode at about 210-230c. Temp control is redic. My daily is a Smoant Naboo with a salad made of various Zeus X atty's and home-made liquids mixed right here in the chemistry wing of my lab (that one spot on my bench). I am *STILL* waiting for my damn Smoant Ladon pre-order from sverseas to show up. It's their next box mod and my Naboo needs a new lil brother. Been in transit for 3 months... ugh
OK
@RustyOldNail On to address your question. In the early days, there was battery. And it was good. Then it sagged. And it was bad. Then there were the first gen regulated mods (cigalikes, the bolt, 510's and 808s). Then came the eGo battery (the 3.4 regulated cigar shaped thing with the big-ass, now abandoned eGo connector). Improvement, but meh. Bucked to 3.4 to mitigate sag, making you chose your disposable atomizer (or rebuildable) if you were lucky, based on resistance and coil count to get the desired affect at fixed (artificially sagged) voltage. THEN came rebuildables (atomizers you can rebuild over and over). What grace! A gift from the heavens. No more awful disposables. And with that came the demand for higher power, as people designed bigger, hungrier coils. Thus, cloud chasing became a thing.
There were a few solutions. The first was a "mech" or "mechanical" unregulated mod. More or less, a tube with contacts you bridge against a high-amp 18650. This was the next best thing, but it was a PITA because voltage sag returned, and so did a few new issues - BIG unregulated power (bridge the battery and now you have a pipe bomb), and the necessity to build your coil to match your needs (requires skill and somewhat advanced materials knowledge). Which was a science all in its own. That's where the coil notation I used actually came from, how to communicate your design spec in a meaningful way to reproduce it. Higher wrap count / lower wrap count / Dia + Ga.
Then came the regulated mods! Hooray! SCIENCE! This generation of mods were lower at first. pushing 7, 10, 15, and maybe even upwards of 20 watts if you got spendy. These used variable voltage. The VariTube is an excellent early specimen if you want to see what it looked like back in the early 2010's. It was rudimentary voltage control, but it worked.
https://www.thehouseofvapor.com/Vari_Tube_Gen_2_Black_p/1170.htm
Then came variable wattage. A whole new ball game. Keeping the wattage consistent across battery cycles was a game changer. Now you could always be sure your wattage and output was rather on point, save, and effective. No more guessing. It was also more efficient than VV.
Now we're to the point of using tech called TCR (temperature coefficient of resistance for you TLA nerds). This means that we observe the temperature in the heater itself using only the resistance changes under workloads, and more or less feed the input to a PID controller which then uses something like PWM to regulate the driver that controls the heater circuit.
Now - this is a rather idea setup. A lot of the work, programming, and economy-of-scale is done. You have an end-product that you can buy off of the shelf ranging fro 25 to 250 bucks, that puts out power in one of two ways. Variable wattage, and TCR are most common. It is uncommon to see VV now (the notion is antiquated and abandoned).
BUT. The issue we have here, is that we want to feed rather unfettered DC output to an inducter driver. The VV solution from the early days would be far more friendly in terms of trying to match output to input, but there is still no guarantee you have clean power coming out. Because it's driving a dumb heater resistor, it is very rudimentary in nature and I would not suspect the power to be clean enough not to piss off the ZVS circuit without a LOT of further investigation and some advanced bench tools and knowledge. The outputs of a contemporary Ecig mod aren't ideal (at least IMO) to be fed to a ZVS driver.
Another custom non-ZVS driver, perhaps. But probably not our dear friend, the trusty ZVS, I would wager. I would love to be wrong on this one, but my gut feel is that it's probably not ideal.
Oh, and FWIW, we don't ever use the balance chargers in our mods. Even the good ones, typically. We all have tabletop 18650 computerized chargers to optimize battery health and maximize charging, for such important devices
The inboard chargers tend to be crap (as most cheap, low tolerance stuff goes) and are generally avoided for that reason. I have never once used mine in a decade. Always a tabletop. Nitecore has some solid options and is often a go-to recommendation. If you use 18650s or other barrel-cell LiON batteries, you NEED one of these in your arsenal. You'll thank me later, lol.