Higher voltage and efficiency

[nuz69]

Originally Posted by BrianG

So, if you have a total resistance of 0.05 ohms for the motor, esc, and wires, that's a loss of 82W on 2s for a system efficiency of 72.67%. But on 4s, that's a loss of 20.6w for a system efficiency of 93%. Big difference there!

I am sorry BrianG, your math is false ^^ This would be too easy to gain efficiency you don't think ?
The motor resistance gets higher as the Kv drops (more turns and smaller wires).
For example you need to double the number of turns to get the Kv divide by 2, that means for the same volume of copper (both motors have same weight), the wires section/surface is divided by 2, that means the resistance is multiplied by 4 :

R = resistivity * (lenth/surface)

So the R*I² loss is exactly the same for the two motor (I multiplied by 2 but R divided by 4). Someone explained this point above. And in reality it's not as simple as that. Sometimes it's easier to package thin copper wires in the can, sometimes not, so the resistance is also affected...

But there is a gain of efficiency in the ESC/Battery wires and connectors, and in the ESC. And this is this little gain you have to calculate, do you have some wires connector resistance values ? ESC is like 0.0003 Ohms...