No balancing occurs during discharge. The benefit you are hoping might be realised is to recharge from a lower SOC giving more time for the cells to come into balance during the charge cycle. By most accounts it probides little benefit as the underlying problem is usually attributed to variances in cell IR which deep discharge does nothing to improve.
It depends on the schematic.I do not know the dji battery connection but it is not rare to move energy from cell to cell by dcdc technique.
That definitely doesn’t happen in the DJI packs. Where have you seen the so called DC-DC technique? I’m going to suggest that it is exceptionally rare. Why would a manufacturer go to that expense in circuit implementation when switching in a ballast in the high cell(s) does the job?
You can study circuits for power management from Texas Instruments, Linear technology and so on. The problem with balancing is quite serious. The discharging balance is the way to keep long battery life.
No you can not do it because the battery of the phantom has 4 cells and on the connector are only + and -. The pins are connected in parallel so you can put charging connector in the both position.
The battery management SOC operation and implementation (Texas Instruments solution) is well known. We are interested to learn from you an example of the DC-DC technique you referred to.
Actually with the pack apart there is no reason the cells could not be connected to the balance port of a charger as the cells are wired with balance taps like any conventional dumb LiPO.
From memory the screenshot you posted after a full charge showed over 200mv variance in cell voltages. Take it for a flight low and close and fly down to 20% and then have a look at the log in airdata from the flight. I suspect it Ian ready for retirement.
You can’t.
