I have recently purchased an SKR 1.4 Turbo which I intend to add to my P3Steel printer. I have an old power supply which appears to have dual outputs [COM COM +V +V]. I want to connect this to the board but the board only has a +V -V connector. The supply is rated at 12 V 15 A which I believe is what is required by the board.

Do I have to connect both +V from the power supply to the +V on the board, and both COM (-V) on the power supply to the -V on the board?

I guess what I'm asking is whether the full 12 V 15 A is only achieved by using both of the outputs together?

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  • $\begingroup$ Is this the manual to your board? www.roboter-bausatz.de › pdf › BTT-SKR-V1-4-Instruction-Manual $\endgroup$
    – Perry Webb
    Jul 20, 2021 at 18:25
  • $\begingroup$ This might give you some technical infomration: amazon.com/… $\endgroup$
    – Perry Webb
    Jul 20, 2021 at 18:32
  • $\begingroup$ It's possible the power supply has both force and sense lines. However, sense lines are usually marked S- and S+. $\endgroup$
    – Perry Webb
    Jul 20, 2021 at 19:06
  • 1
    $\begingroup$ You'll be fine just using one of the "outputs" - in fact, they're connected right on the PCB, unlike the multiple +12V rails you may find on a computer PSU. There is no benefit to running both leads, since the connector on the SKR 1.4 T would be the limiting component here. If you're using an external MOSFET for the bed, you could (and should) use the second set of connectors though to keep wiring tighter and spread the load a bit. $\endgroup$
    – towe
    Jul 21, 2021 at 6:19

1 Answer 1


My Ender 3 has the same connections on the power supply. As received from the factory, the machine runs off one set (mainboard, bed heat, hotend, and fans) and the other set is left open (I think they're connected inside the power supply). Given mine is a 300 W rated supply like yours, you should be okay drawing 15 A connected to either V+ and either COM terminal.


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