Oh yeah, this is wildly unsafe. I would have personally used my IR meter, capacity tester and a high grade adjustable voltage/current charger to baby these cells as much as possible.
I have two destroyed "hoverboard" batteries (10s2P) that I'm having a hard time disposing of because the casing on some cells has been breached. And I live in a large metro area. I'll probably end up having to disassemble the battery so that I can drop the intact cells off for recycling. And the destroyed/breached cells will probably end up in a landfill somewhere.
Wildly unsafe? That seems a bit harsh. I'm pretty sure that the cells he's using don't have the safety mechanisms common with modern 18650 cells. So I certainly don't think this is a "safe" implementation. But he at least did a decent job of building the battery with an appropriate BMS, reasonable shock protection and insulation and a decent case and monitoring system. He even made a point to warn others against copying what he did.
Exactly this. I would call it "moderately" unsafe, rather than wildly. He does use a BMS, at least. But i did mostly want to share the video because it highlights the level of things that can be made or repurposed from stuff we throw away.
The guy who made the video requested and received a data sheet on them. That sheet said that the cells could be recharged not less than 300 times. I've seen other 20400 cells claiming 500 cycles.
Always has been.
