Quote Originally Posted by metric_taper View Post
The reason for this warning, you may damage that cell by overcurrent or overvoltage breakdown of the insulator that prevents the cell from going into thermal runaway,
This can result in the unwatched charging, burning the location to the ground. Cheap import batteries are known to do this as well (any advice relative to repairing battery packs, for affordable cells?).
We foolishly trust these compact high energy density bits of technology to not burn, just saw a video of a dog that burned the house down biting the phone on the couch, the homeowner video to watch their canines during the day remotely, did not save them from loosing the shoe biter.
And the recent warnings of charge battery banks going into thermal runaway on aircraft. Fireball from overhead stowage, and the guy looks at his bag next to the fireball and has no clue what to do ..... HEAD THIS WARNING!
Quite true. Just because cells have protection circuitry (hopefully!) doesn't mean they can be abused. Storing a lot of power in a small space is dangerous no matter what. Be very careful working with lithium batteries!

BTW, the most dangerous part of the battery is the polymer, NOT the lithium. Odd but true.