12V 25A PowerSupply

To test my LED Stair Lighting Controller boards I needed a 12V power supply that can deliver a lot of current. For this I chose a SP-320-12 from meanwell. However with the screw terminals it is not easy to use on a lab bench, also there is no display to monitor the output current. Therefore I build an enclosure around the PSU, and added a volt and ampere meter.

The meter I chose was a cheap one from AliExpress: DC 0-100V 30A 50A Dual Digital Voltmeter Ammeter Panel with DC 50A/75mV Shunt LED Red Display

 

Everything mounted in the enclosure (Hammond 1598JSGYPBK):

To limit the voltage drop of the wiring I used a lot of wires in parallel, and braided them to keep them close together:

Front panel connections:

The banana connectors are special ones that can handle 25A. (Red: Farnell 1698956 and Black: Farnell 1698957). Standard ones would probably melt in this use case.

In the back of the enclosure I have made some holes for the air to get in the enclosure, on top of the fan of the PSU I made a air duct to the top of the enclosure. In the top lid I made holes for the airflow to exit.

Front-panel:

2 comments

3 pings

    • Bob on May 12, 2020 at 04:58

    Clean and tidy! The chimney is a great addition.

    For the DC connectors, consider Anderson Powerpoles. They can handle large currents better than banana plugs.

    If you don’t mind violating the warranty, you might dig into that Meanwell supply and see if you can bring the voltage sensing out to the other side of the current shunt for better output voltage regulation. Or even bring it out to the front panel for remote sensing.

      • Stynus on May 12, 2020 at 22:11
        Author

      Thanks :).

      The Anderson Powerpoles connectors are a good option. For my application the banana plugs are enough, with a high current banana on the cable it does not get hot.

      For the sense it may be better to use a power supply that already has this (some meanwell PSUs have this). But for my application I do not care for the drop over the shunt since it is only 0,0375V at 25A.

      Regards,
      Stijn

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