Originally Posted by aeajr

Generally you go for lower amps and higher voltage.

In general, for typical electrics in the 1 to 6 pound range amperage between 10 and 50 amps is a good working range. You can run higher amps but typically I would say, as you approach 40 amps you should consider going to a higher voltage.

As you go to a higher voltage you will spin the motor faster. So a motor of 1000 kV on a 3 cell lipo, 11.1 volts is going to try to spin at about 11,100 rpm. If you put a 4 cell lipo on it it is going to try to spin at 14,400 rpms.

If you use the same prop on both packs the amperage draw on 4 cells will jump a LOT and perhaps higher than your ESC or motor can handle.

So, motor kV, prop size and battery voltage is a balancing act.

If that is still confusing then consider the gears on a car or a bicycle. The higher the kV, the higher the gear. Now, if you want to spin a small prop you can run in a higher gear, a higher kV. If you want to spin a larger prop you run in a lower gear, a lower kV. The car's motor is the same, or your leg strength is the same, you just use it differently depending on what gear you are in.

In "Everything you wanted to know about Electric Flight", look at these three chapters but don't look at them as stand alone discussions. Look at them as three aspects of the same thing, how to balance kV, battery voltage and prop size.

3 ............Sizing Power Systems
4.............Props vs. Amps
45 ...........What Do Motor KV Ratings Mean?