I just tried balance charging with a 5A battery active balancer that I bought from feebay and wanted to share the results. If this works it will be cheaper than sourcing a balance charger that handles up to 12s. I’ve only found 2 of those and both are in the $200 range. The 5A active balancer was around $60 or so.
So I used the charge (not balance) function and left the 5A active balancer plugged in to the balance lead. It stayed cool at a 2A charging rate and the cells remained balanced within .03v
The new version of this already has a jst-xh connector so you wont have to solder and shrink 15 wires then solder 15 connector pins like I did.
You might have to charge your pack slower than 2A when you go to higher cell counts. Keep in mind that the 5A rating is this active balancers maximum and it doesnt balance as fast when the cells are closer together.
Will experiment with this further and see if the cells remain in balance all the way to the finish. As you can see from the pics I stopped at 4v just to check the progress so none of the cells would go over 4.2v and overcharge.