I want to throw out one more idea, that may be buried in the above but I thought should be stated more directly. It was pointed out that few 18650 batteries have a true continuous discharge rating above 20A. Battery makers, particularly relabelers, are famous for overstating specs (known as "lying" in any other context). If your battery is rated above 20A continuous then you want to investigate further, and it might be a Very Good Idea to assume 20A. That is just an aside to my main point.
A regulated mod is essentially a black box in between the battery(s) and coil. That black box converts voltages and current back and forth to achieve a continuous power as the battery voltage declines from about 4.1V to 3.2V or whatever voltage the device cuts off at. Lets assume 3.2V although some people remove their batteries at a higher voltage in an attempt to maximize the battery life. And your device may "die", indicating a flat battery, at some other voltage.
Ohm's Law says power (watts) = voltage * current
If you assume a conservative upper limit of 20A per battery, then the maximum power you can safely get from that battery = 3.2*20 = 64 watts. If you have a dual battery mod then the maximum is double that, or 128 watts. I'm assuming a 3.2V cutoff but you want to check your particular device to see where it cuts off.
In principle you can get up to 20 * 4.1 = 82 watts, but only with a freshly charged battery. We want to conservatively calculate worst case, which is the last puff you take before you remove the battery by choice or the device cuts off.
The above is a very conservative calculation of the maximum power you can draw before you start pushing envelopes. If you push enough you may get the picture I posted above (jk! but something slightly less bad could actually happen, like the battery venting or something similar, or just a very poor battery lifespan)
The actual voltage across the coils and the current that passes through the coils will likely be different because that black box is converting voltage and current. But the important point is that, assuming 100% efficiency of the converter, the current drawn from the battery will always be the power level selected in a VW device divided by the battery voltage.
Since voltage converters do not usually run at a full 100% efficiency then this assumption adds a liberal bias to things but I don't believe those efficiency numbers are widely available. This counteracts the idea that we don't actually run our batteries "continuously", which in principle means from a fully charged state to depletion at ~3.2V or whatever without a break.
If you choose to run your mod at greater than the continuous rating, you will probably live, if you don't exceed it too badly
. If you do this, you are now "pushing the envelope" and you are on your own because the results of that push, depending on how far you push, are way outside the scope of any general rules of thumb. But we can see clearly that the 367.5 watts calculated in the OP was quite pushing the envelope!
