Duet3 VIN fuse



  • Hi everyone!

    TL;DR: how much current can draw the Duet3 through VIN terminals? I see on the dozuki portal that the VIN fuse is specified at 10A, but the board came with 15A one.

    A bit of context.

    I recently got a Duet3 MB 6HC to revamp an old 3DSystems Cube Pro Trio.
    The final configuration will feature:

    • 24V PSU + 24V/12V stepdown converter
    • 2x 24V Dyze extruder+hotend w/pt100
    • 3xNEMA17 for X&Y axis
    • 1xNEMA23 for Z axis
    • 1x220V Heated Bed (w/SSR)
    • 1x220V Heated Chamber (w/SSR)
    • 1x12V 800l/h water pump for watercooling
    • some 12V fans for the wc radiator and whatnot

    and obviously a Duet3 MB 6CH w/pt100 daughterboard & RPi 4B.

    Initially I thought of using DC/DC SSR for each one of the 60Wmax DYZE hot ends since I was not comfortable running ~230Wmax through the Duet3; given the 24V VIN, it was too close to the 10A of the VIN fuse.

    (Don't mind the 12V stuff since it would be powered directly from the stepdown DC/DC converter; it's the watercooling pump&fans and it would take waaay more than the 800mA total rated from the D3MB)

    But now I see the board comes with a 15A VIN fuse and I wonder if I can safely run those 230Wmax and ditch the SSRs for the hotends.

    Thanks for any reply and have a nice day 🙂


  • administrators

    There are two VIN power inputs to the board:

    https://duet3d.dozuki.com/Wiki/Duet_3_Mainboard_6HC_Wiring_Diagram

    07e0ce17-33a1-4b2e-ac6c-cf36255c9912-image.png

    Both are fused for 15A on production boards. That said, you are well under the limit: As you run both hot ends at 24V, together thats 2x60W = 120W @24V =5A. That leaves 10A for the stepper motors and onboard power requirements which is plenty.


  • administrators

    I have updated the documentation.



  • thank you for the kind reply, much appreciated!

    have a nice day/evening 🙂


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