Hello.
I recently got some brushless motors. I checked the specs on it, and it said that the “load current” is 25.2A. So, I got a 30A ESC on it.
Now I’m wondering whether those amps on the motor are how much the motor is going to require in normal use. As I understand it, the voltage will be varied by the ESC so that the motor will slow down or speed up upon throttle change, which also changes the current output of the battery to the motor.
But is it the amp draw on max throttle?
Usually motors have a thrust test table that shows thrust and current draw at various throttle settings. But if you just have one value you can assume this is the max throttle current draw. So at lower thrust, the current draw will be less.
As you change throttle, on brushless motors it’s not only the voltage that changes, but rather the timing between each section of the motor (that is why brushless motors have 3 wires).
Also another thing to remember is that the current draw will also change when you use different propeller, as bigger props require more work to get spinning and will have higher current draw.
I have a few articles here on dronetrest explaining how motors work and how to choose the right motor/ESC/battery for your drone if you want to learn more :-). Or you can ask.ore questions 
Hi, could you point me in the right direction please? I need to calculate the current draw based on motor/ESC/battery but I can not find any article about it.
I would appreciate if you could help me with the formula to calculate this please?
Many thanks.