There is also a lot of crap posted about Ecigs. Chemical makeup is vital for sure....................It's a big topic, and people think they can just go out and connect up in series sometimes with a walmart flashlight battery. It will all likely all blow up quickly (pipebomb). I mentioned drain rates...........that is v important. Reputable source with a not too low resistance coil (so will not drain the batt that fast), and my opinion was it's safe enough with only some understanding.
Go below (as said) 1 ohm and you had better really understand ALL of it..batt types, drain rates, DC circuits, ohms law...real deep understanding. I do sometimes go low after building my own , but I think I have a good understanding and check with multimeter type things and etc......I also KNOW all about what the capability of any battery is, and that's not the specs on the side I am using.........one other start resource..........I am not telling others what to decide, just that I am happy with the level of risk I decided was acceptable for me:)
EDIT: Another resource :).........The industry is not regulated at all, and WWide they are working on how to. Daft reports from harvard about chemicals, just made Harvard look daft and did not help. Biggest issue I see is how do you stop that idiot making a v potential pipebomb due to plain dumb ignorance, and also some real crap out there for sure. We all accept risk everyday, and as say very personally above is hopefully some way to explaining my personal rationale. Huge topic and I have probably used enough space.
Before I leave it I found that resource you partly quoted. Some added rest of quote is as follows:
the batteries are especially prone to overheating because smokers use incompatible chargers,overcharge the e-cigarettes, or don't take sufficient safety precautions. For example, many e-cigarettes are made to plug into a USB port, which smokers may take to mean the devices can be safely charged with a computer or iPad charger. But if left too long in a common USB port, some e-cigarette batteries can fry. Resource I assumed was it anyway.
Yep these are not toys for sure, and easy to see where some sensible regulation might help - away from the impossibility of idiot proofing it. regulated device from a reputable place, above 1 ohm ..............following specs............Not a sport where it's OK to assume one knows better. Personally I also rest a battery before charging and rest after too. I will recharge elsewhere but I know what amp outputs and inputs are, and stay as safe as is possible with batts (always some risk same as I let my mobile rest in a pocket near my right bollock etc LOL)..........