Motor connectors: How to choose optimal size?

[jhamel]

It looks like we tend to use large connectors and thick gauge wires on the battery side of the ESC's. How about the motor side of the ESC? What size connectors should be used for 550+ size helis? I mean, several large 700 and 800 size motors come with relatively thin wires. Does it make sense to use 6.5mm connectors on 800 size motors with what looks like 14AWG wires?

[extrapilot]

It comes down to power loss/heating. The loss in a connector can be very small, or large, depending on its size/materials, but also on the mating surface area.

One way to find out how you are doing is to use some temperature-sensitive tape (indicator of whatever type), and see how hot they are getting in flight. If they aren’t above 150F, you are fine. If they are 300F, you are losing a lot of power, and you are getting close to the point at which you can melt some solder…

Look around for ‘temperature recording labels’ or some such description online.

[jhamel]

Originally Posted by extrapilot

Look around for ‘temperature recording labels’ or some such description online.

Do you have that data?

[desertstalker]

Originally Posted by curmudgeon

Does it make sense to use 6.5mm connectors on 800 size motors with what looks like 14AWG wires?

It wont hurt (the weight penalty is tiny).

A decent way to estimate is work out average current draw using flight time and amount put back into the packs. This can then be used to determine suitable connectors.