3mm/4mm connectors ?

[Barrie Dav 2]

These days many motors come with 3mm connectors. I've normally replaced these with 4mm and standardised on 4mm for general use. Why? I dunno... So I ask the question, 'At what current level is it advisable to use 4mm instead of 3mm?'

[Ben B]

SMC say 3mm gold bullet connectors are okay up to 50A and 4mm up to 80A which sounds about right to me.

If you are using them on motor leads then I think you can add a bit extra on top of that because the motor leads are not continuously providing power to the motor due to the phasing.

[Barrie Dav 2]

OK Ben. Thanks.

[Romeo Whisky]

I've been flying only electric since the early days (10years+), and to the extent to which there is a "standard" at all (which isn't much), a long accepted "standard" for anything up to 4S LiPo was always 3.5mm gold connectors motor to ESC, and 4mm ESC to Battery. The 3.5mm are quite stubby compared to 4mm and this is often useful for keeping weight down and connection leads less cumbersome. The motor usually uses all male connectors, but the red + lead of the battery itself should alwaysbe female.

I know some use Deans plugs these days but I hate them.

[Barrie Dav 2]

Thank you for your comments RW. Yes, the advantage of the 3.5mm is that they are less cumbersome. 4mm are no problem if you have plenty of space but in, perhaps, a glider they are sometimes difficult to accommodate. I too, hate Deans but I use them ESC to battery. They are very difficult to separate but I suppose that that's the idea.

Edited By Biggles' Elder Brother - Moderator on 14/11/2012 17:10:23

[John Privett]

Posted by Romeo Whisky on 14/11/2012 13:58:08:

The motor usually uses all male connectors, but the red + lead of the battery itself should alwaysbe female.

I know some use Deans plugs these days but I hate them.

Why do you say female for the battery +ve lead?

I started using 4mm connectors on my batteries with my first electric models and opinions were divided as to what convention to use. I went with the majority (locally, at least) using the male connector on battery +ve. Some used (as you suggest) female for battery +ve and at least one person back then used female connectors for both battery leads - no chance of shorting the battery to itself, but a significant chance of connecting to the ESC with the wrong polarity! My recent electrics use XT60 connectors - I hate Deans too!