Paul,

You are missing my point. All ESCs have internal voltage regulators. Most make the regulated 5V available for RX and servos (AKA BEC) and some do not. In any case the regulator is in the controller. Controllers that are "not BEC" have simply cut the red wire for you. Assuming the 9V battery is capable of 1500mah, a 1.5A brake can be activated theoretically for 1 second 60 times. Factoring in voltage droop and brake coil drop out current, 20 to 30 activations is more likely. The 9v "transistor battery" I mentioned has no where near that capacity.