5Amps, get a cheep 10Amp ESC and use the Arduino's PWM to set the speeds.
I wanted to try and understand the control of brushless motors - I don't want to just buy an ESC off the shelf!
When you say internal switch resistance, do you mean the resistance of the mosfets inside the chip? Would it be better then if I built a circuit completely out of external mosfets to control these motors?
Thanks for the reply 