[Make It Extreme] is working on a battery pack for an e-bike that has some interesting design features. The guts of the pack are pretty much what you’d expect – recovered 18650 lithium-ion cells.

Over at Hackaday.io [AndyHull] popped open some cheap LiPo battery power ... The power packs [Andy] looked at have a TP4221 controlling the charge cycle for up to four 18650 LiPo cells connected ...