I have 4 18650 batteries and I want to make a battery pack of it. If all the batteries were new and had similar voltage/capacity I could easily charge them all together in parallel with my charger. However the batteries have about 10% difference in capacity so I need to charge them using a balance wire on each battery/cell.
My problem is this: I have 2 circuits that I came up on my mind (drawing below) in such a way that one circuit is for charging and the other for discharging. So how do I do the wiring in such a way that I can solder the wires to the batteries (spot weld) and have a DISCHARGE port (+ and -) and a CHARGE port (GND and cell 1, cell 2, cell 3 and cell 4)?