Yes, 15-20A (or maybe 10-15A) would be for long range, Lo speed... TBD
I am aware of the Bafang controller being 30A... so, if I need power, I can crank up the amps no problem with an external controller all the way to 40-50 Amps if needed. I may use a CA-3 for the display, as you can set-up a 3...