Originally Posted by healthyfatboy
Your last statement is false. The way the brushless ESC works is that is pulses at full current for a set time. By varying the duty cycle, you get your average current that's delivered to the motor. So if your motor is a 20A motor pulling 20A and you have a 25A ESC, each pulse delivers 25A but only for 80% of the time, giving you an average 20A. You'll only measure 20A even though it pulses at 25A. If you try to pull 30-35A out of a 25A ESC, it'll try to deliver 30-35A, whatever the motor asks for, so it'll be full on and will eventually blow your ESC.
Don't do it, even if it's worked for you before. You're just asking for trouble.
You are totally correct.
You motor prop/combo should never pull more amps then the esc can pass through and the battery can deliver, at full throttle. It will draw this current and voltage many times a second at full and your watt meter will only give you the average.
Running a system like a 3900kv motor rated at 40amps max with a 6x4 prop and drawing 58amps with a 60amp esc at 1/2 throttle will still eventually kill the motor.
This is why we all don't use 5000kv motors and only use 1/2 throttle.