Yeah, I didn’t watch this video b/c I’m at work, but I have seen his ebike video so I’m assuming the construction is similar.

It’s just that all the fuses and BMSs can’t protect against a dodgy cell that decides to self-immolate. For cheap, disposable devices that are only meant to be charged 5-10 times or less and then thrown away, I’m super wary of the batteries that are chosen for those. Have seen too many things burst into flames and even expensive well cared-for devices turn into spicy pillows.