[tinfever]

Unfortunately I haven't implemented cell balancing in the firmware. This is for a few reasons:

On the V6 batteries, you could theoretically install the missing resistors and handle the rest in software, but the balancing would be very slow since it would also have to go through a 1K resistor Dyson included on the other side of the internal balancing MOSFETs. On the V7 and up models, they actually shorted the internal balancing MOSFETs of the ISL94208 on the PCB so you'd have to cut the very fine traces here and then solder on balancing resistors. I think you could actually just place a short in place of the balancing resistors because of the 1K resistor already in circuit.

All said, I figured that of the limited number of people willing to take apart their battery, buy a programming tool, and install my firmware, there would be even few willing to make those very delicate modifications. And anyone willing to do all that probably already owns a bench power supply they could use to rebalance their battery pack manually.

I'd initially planned on adding cell balancing until I saw that the ISL94208 balancing connections where shorted together on the PCB. That's something that just can't be fixed in software. Maybe one day I'll add balancing to one battery, just to show it can be done.