Good day.
Individual unprotected lithium cells are recharged with proper devices that follow preset voltage/current recipes to reach optimal states. I have a few, they perform fine. Sometimes I apply 4.1000 V directly and has worked fine foo.
Can cells that contain protection circuitry in them have a higher voltage source applied to them instead of a proper charger and the protector circuit will manage the conditions as if it was a charging circuitry, plus take care of the overdischarge also ?