Bottom line, you wouldn't want to use those Panasonic A & B batteries nor an 18350 battery when using coil resistances below 1.0 ohms. Sub-ohm is not an application for the 18350 size batteries.
Steam Engine | Vaping related calculators
This calculator takes APV efficiency into account and calculates the amperage actually drawn from the battery. The DNA20 is 93% efficient, according to Evolv. I dropped that down to 90%, due to the wiring for switches, grounds, battery, charger, etc. My regulated mod uses relatively large gauge wiring, with short paths, so I would not think it is losing much efficiency through the wiring. I'm using my Hanamodz V2 for this example, btw. The 18650B is rated at 2C, or 6.8amps continuous and 12 amps pulse(5-6 sec.).
According to the above calculator, this battery would be within its limits until you got to around 3.3-3.4V battery charge vaping at 20W on a 0.8 ohm coil. At about 3.3V, you hit the amp limit. At 3.5V, 20W would be pulling 6.35 amps(~93%) and 22.2 watts from the battery. Not exactly "safe", I suppose, but still within the continuous discharge capability of the battery. And only about 50-60% of the pulse discharge capability. With the battery at 4V, you're pulling 5.5 amps(~80%) of current at 20W.
Let's use a more realistic example. I've been vaping between 16-18 watts on my Hana. At 18W and 3.5V battery charge, you're pulling 5.71 amps(~84%). At 4V and 18W, it's 5 amps. At 16W and 3.5V battery charge, that is 5.08 amps(~75%). At 4V and 16W, that is 4.44 amps(~65%). At 16W, you do not hit the amperage limit until ~2.7V battery charge.
How many of us are really vaping at 20W on a regulated mod, taking drags longer than 5-6 seconds consistently? Even if you are, it seems like this battery is relatively safe for the average user. I understand your points about it being a "low-drain" battery and using a chemistry that is not as safe as IMR, but neither of those really come into play if you pay attention to battery charge and know the limits of the battery and what your current build is doing in terms of battery load, correct? In the event of a battery failure, or venting, etc., this battery will not be as safe, due to its chemistry, but other than that, it seems perfectly suitable if used properly.
Are you simply putting this out there for people who do not bother figuring out the amperage draw of their current setup or ignore battery amperage limits?
Basically what I'm wondering, is if you're operating within the amperage limits of the battery, why is safety an issue, whether or not the battery is "low-drain" or "high-drain"? It is rated for X amperage draw, and if you are not operating extremely close to that amperage limit, is should not "blow up" or vent, correct? My understanding of a "high-drain" battery, is that you have a higher amperage limit and a "low-drain" battery has a lower amperage limit. Is that correct? I'm not a battery expert, so I'm just trying to make sense of why this battery should not be used, if you are operating within its limits. Any battery should be operated within its amperage limits, regardless of chemistry or if it is a "high-drain" or "low-drain" battery.
I am not trying to say you're wrong, but I would like to get some more info on this and you seem very knowledgeable on the subject. Sorry for the wall of text, but I'd really like to figure this out, because I have one of these and I like the idea of a 3400MAH battery for using in my Hana while I'm out. If it is truly unsafe for use, I will not use it, but based on the info I have and the setup I am using it in, it seems like it should not be an issue.