Hi! So my first build will be 83mm wheels, 12mm pulley system from enertion(36t/ 15t), sk3 245kv, vesk from enertion, and 6s or 8s 8000mah battery (2x 3s or 2x 4s 8000mah). So i’ve read that higher volts= better, but do i need change motor to lower kv, or 8s with 245kv is fine? Also IMAX B6AC V2 Professional Balance Charger/Discharger will charge x2 4s 8000mah at time?
If you charge them in parallel, then yes. I can’t answer your rpm question, but someone else will.
245 kv with 8s is perfect!!! (7245(4.2*8))=57,624 erpm Just below 60k erpm with fully charged cells. Your setup will work great with the vesc.