If thats an 6s rc charger then yes it works great doing that.Just build custom 6s balance leads and wires doing so. Its rather common when doing rc when you talk about high power that you use multiple battereis in series. And they are kind of charged like you say.
Do note that you need to custom build the contacts unless they exist!
hello ebike, not sure what you mean, by just using a power supply? i thought you had to charge a 12s battery using balance leads so each cell has a chartering circuit? are you saying you can charge as 12s batt connecting just 50.4v across it?
Yes you can but I don't recomend doing that unless you are closely monitoring each cell string voltage so that none go above 4.21v
If the pack is out of balance it will just keep charging till it hits the 50.4 volts
This can mean that an out of balance pack can push some cells above the rated voltages causing a fire hazard....
But saying that, I am just sat diagnosing a faulty ebike battery that has gone below cutoff voltage by individually charging each cell string to 3.7v storage voltage and let them sit with BMS disconnected to see if there are any self discharging cells... This pack has been sat for months and was switched on when it arrived so it could just be the residual power used by the BMS that has taken it low...