I do have a bunch of 18650 LiPo cells, salvaged from various sources. Now, I happened to come across a variety of power bank cases on Amazon which mostly look like this:
Even a cursory look tells me that these are designed for 20 cells connected in parallel, without any individual cell balancing. As far as I understand it, this is a complete no-go, especially if you're considering salvaged cells with mixed capabilities?
Or is this configuration actually safe to use, because the individual cells can't be charged above 4.2 V (or whatever the cutoff voltage of the charger is)?
Addendum: I just found Can I use multiple 18650 batteries in parallel with a standard MicroUSB 3.7V charger board?, and based on that answer, it would seem my original hunch was correct? If one cell shorts out, then this thing would go up like a napalm charge?