ORIGINAL: wreck_em_all
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...
Ahhh... I agree with you there... I never had a non-BEC ESC, so I didn't know if they typically use the RX power to run the control section or regulate the ESC batt voltage down... the latter makes the most sense to me, as you said...
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.
You're off by a factor of 60 here... 1500mAh = 1.5Ah which means you can draw 1.5A for one
hour, not one
minute. So you would be able to apply a 1.5A brake for 1
minute 60 times. 9V NiMH cells have only about a 200mAh capacity... I guess alkalines probably have closer to 600-700mAh, like RCGuy said. Internal resistance of these cells is quite high, so I'd imagine you'd get quite a voltage drop with a 1C+ discharge rate. If you only apply the brakes for a few seconds each time you land, and can still get decent braking with the loaded voltage, I'd guess the batt would take the brief heating with plenty of time to cool down in between. Assuming a 1.5A braking current, that would give you a 1/2 hour of braking on one 9V cell...