enter image description hereI have a Dell BTX power supply totaling 750 W. It is a little bigger than the usual ATX supplies.

It has besides 3.3 and 5 V, four different (colored) 12 volt lines each capable of 15-18 A.

This is not the regular ATX power supply with only one 12 volt line!

Previously I rebuild several ATX power supply's to a max 12 volts bench power supply.

Now I want tot rebuild this BTX power supply to a 36 - 48 V power supply.

Can I and how can I safely combine the different power lines?

Thank you for you idea's and suggestions!

  • added : I also thougt it would not work but i find very confusing info on some sites of people changing 1 server power supply to 24 V
  • 1
    \$\begingroup\$ Most likely those 12V lines share a common ground, which cannot easily be lifted. I.e. No, you probably connect these 12V line in series to create higher voltage. \$\endgroup\$
    – Klas-Kenny
    Commented Nov 23, 2021 at 12:27
  • 1
    \$\begingroup\$ Without the schematic, it is difficult to say. But let's say the 12V lines are emanating out of different regulators, ask yourself what would happen, if one of these breaks down. \$\endgroup\$
    – Syed
    Commented Nov 23, 2021 at 12:35
  • 2
    \$\begingroup\$ @Klas-Kenny: I think you left out a "cannot" in your comment. If the 12 volt supplies have a common ground, you CANNOT connect them in series to create a higher voltage. \$\endgroup\$ Commented Nov 23, 2021 at 17:20
  • \$\begingroup\$ @PeterBennett Oh, indeed I made a typo there. \$\endgroup\$
    – Klas-Kenny
    Commented Nov 24, 2021 at 6:45

1 Answer 1


Generally, you can't combine the outputs if they share a common return path (or ground).

Almost all ATX and BTX PSUs having multiple 12V outputs actually have a single 12V output. Here's an example:

enter image description here

Image Source: Personal Archive

As you can see, there's only one output and two filtered outputs are taken from this single output. I don't think your PSU has a different structure for different 12V outputs.

So the short answer is, no.


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