Problems with connectors

Hi everyone,

I just got a Smoothieboard Beta!

It looks great, but when I came to selecting connectors I ran into trouble. The big power connectors are simply too small for heavy duty heatbed wiring. There was one large Phoenix connector supplied which looked like it would be for big mosfet power, but doesn’t fit there.

The connectors for motors, endstop, thermistors are ok, although the space is not quite enough for Molex KK connectors in places. 0.1" or the 3.5mm phoenix for the motors is a reasonable setup. But the multiple footprints on the power connectors doesn’t work for me. They take up board space but don’t allow for the connectors I actually want to use. The 5mm Phoenix are pretty standard and capable of high current and big wires.

I have a few other niggles as well, but really the power connectors are a no go for me. I realize this is a beta and may change. Is it just me, or do others have the same issues?

Imported from wikidot


Hi bobc !

The 5mm connector is only for VBB ( the stepper motors input ).
All the other connectors are 3.5mm.

For the bed, you’ll want to use a 3.5mm connector on the “Big mosfets power input” ( so separate power input for steppers and bed ).

See the schematic on the right ->

If that’s already what you are doing, it seems strange that you have a bed for which this is inadequate. I use those connectors for a 24V/400W/300x300mm heated bed, and they have worked fine for weeks ( with 220 max_pwm ).
And it’s the hugest bed I can think of really. What bed are you using ?

Cheers !

Obviously you are just trying to justify design decisions you already made. I would more be interested to hear from other actual users :wink:

If mosfets are rated 20A each, I want to use connectors rated for more than 8A. Typical heatbeds use up to 15A.

It is about the “does what it says on the tin” thing, and the 3.5 mm connectors don’t.

There is space on the PCB to mount 5mm connectors, everyone else uses them, I can’t see any reason not to use them. If your attitude is “Smoothieboard is perfect and there is nothing to improve”, there is nothing more to discuss I guess.

It would be nice to have a board I can order off the shelf and use without mods, recommend to friends etc, but it doesn’t have to be this one.