Kossel Power Supply Options

Research mode again…

The design of the Kossel Mini printer leaves very little room for a power supply so I have been exploring a few different options.

Starting with the options for just actually mounting power supplies, from what I can see there are only really three options for the Kossel Mini:

  • Attach to the side – Attach directly to the 2020 profiles on the side.
  • Attach to the top – Use the unused space on the top for mounting.
  • Don’t attach at all – Keep the power supply as a separate entity all together.

For my own personal perspective I see a problem with the first two options which is purely aesthetic, I really don’t want to see a big power supply bolted to the side or the top of the printer, lets face it they are pretty ugly, I’d rather hide it as best as possible.

In terms of actual power supplies there is a number of options that seem very acceptable in terms of power supplies that all have their merits

LED Strip Power supply

These power supplies are usually advertised as LED switching power supplies, However they can happily run a 3D printer and pretty much any electronics project. However cheaper versions tend to develop faults and when buying these its best to ensure you get one with a automatic fan (instead of always on) so its not making a ton of noise every time you turn it on. These power supplies require mains wiring which can be dangerous/deadly and also have touchable contacts which should be encased for safety.

Types:  12/24v, 20-40amp,

Pros:

  • Affordable
  • Widely used (Tons of printed parts available)

Cons:

  • Mains wiring required.
  • No power switch as standard

Computer PSU

Most computer / electronics fanatics will likely have a couple of old PC power supplies laying around. These can be used as a source of power for a 3D printer but it is important to pay attention to the 12v power output current, as it is possible to overload the power supply (i.e. releasing the magic blue smoke). In order to use a PC power supply you need to hack the on pin to ground so the power supply is always on. Alternatively it is possible to power Ramps (common 3D printer control board) of the 5v standby and control of the PSU directly.

Types:  12v, 10-25amp (maybe higher?),

Pros:

  • They tend to just be laying around space
  • Widely available
  • Cheap
  • 5V power for raspberry pi (Octoprint)

Cons

  • Have to hack the power supply to turn on
  • Most PSU have lots of wires

Xbox 360 power supply

The higher output xbox power supply (203w) gives out up to 16.5amps of current which is perfect for a very small 3d printer without a heated bed and also has a 5v power output which could be used for a raspberry pi or other micro computer. Using the xbox power supply requires a little bit of work removing the connector and writing it up to be always on, However they are fairly small and cheap.

Types:  12v, 16.5amp (203w version),

Pros:

  • Cheap
  • 5V power for raspberry pi (Octoprint)

Cons

  • Have to hack the power supply to be always on
  • Not really enough current for a heated bed

Conclusion

In terms of the Kossel build, however much I’d like to give the xbox 360 power supply a go, the current limitations would mean a heated bed could not be used and considering I was planning to print in ABS this is a no go. Now it is posable to use two different power supplies with Ramp but I think this is just a messy approach unless there is a need to mix 12v and 24v outputs, for instance to heat the bed faster.

 

The LED power supply is a good solution but considering I’ll be looking to use OctoPrint through a raspberry pi the PC power supply seems the best approach at this time, not to mention I can give Ramps the ability to control the PSU and can power the board of the standby line from the PSU.

Anyway I hope this research helps someone and I’m pretty sure there will be a follow up post in the near future showing off modified PSU controlled by ramps.

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