alt Hacker NewsIsn't the problem with parasitic charging? Suppose you had a bunch of used 18650 cells. To scale the electronics, they'll be wired up in parallel and/or series so the charging logic can be shared, but since the batteries are wildly mismatched, it results in parasitic charging.
That is why you sort them.
Some recent research into that: https://www.sae.org/publications/technical-papers/content/20...
You can also consider maintaining packs together to avoid complicated disassembling processes.