What size should your drone wires be?

  • i: Current(A)
  • : conductivity ( ): Probably copper, 1.77e-8
  • r: radius of wire (m)
  • e: Efficiency of your drone motor+prop combo (watts/kg). A high efficiency drone might be 100w/kg
  • d: Density of conductor (kg/m3): Probably copper, 8960.

That’s it. Any lighter and the motors would be dissipating excess power. Any heavier and the wires will weigh you down. Notice that huge fourth root there - the wire size goes up very slowly! Don’t forget that the current experienced by a given phase of a motor is battery amps / num motors * 2/3. My optimum wire radius is 0.23mm. When I backcalculate the power dissipated at that diameter with the wire length of my drone I get 200mW which sounds plausible.

Here is the working out for this formula:

I suppose you could make this analysis more complicated since the efficiency changes with thrust etc. This seems good enough to pick a gauge though.

It’s 2023

…goddammit.