Multi-Cell Charging Adapter

RC battery chargers perform well, but charging and discharging several single cells means hooking up one cell at a time, which is slow and inefficient.

With an 8-cell balance jack, up to 8 cells can be charged and discharged under management at once.

Since it is hard to always use the same number of cells, I built a charging dock that lets you select the cell count.

Symbol	Role
JP5	Balance jack (6 pins = 5 cells + common −)
JP4	Charge jack
S2	Rotary switch

The operation is very simple. The schematic above is drawn for 5 cells (5S).

As the rotary switch turns, it moves the B+ contact between the balance taps to select the cell count.

Wiring gets a bit troublesome when building the 8-cell version, but it comes together if you work through it one connection at a time while following the schematic.