Should the next Voron exclude the 5V supply?

[mggevaer]

It seems that lot's of printer control boards, especially the ones configured to work with Klipper have 5V pins to which you can hook up a Raspberry Pi.
For example, the Voron 2.4 manual, which uses the Octopus v2.4 as an example has both a 5V power supply, but also uses a board as example that can make the 5V supply obsolete.

Is there any reason why the next Voron shouldn't simply not include a 5V power supply, saving some cost and simplifying the wiring of the machine?
Or at least describe 2 options, like with the toolhead PCB board.

Currently kit providers such as Formbot are essentially required to include a 5V supply or they risk customers being unhappy because their kit doesn't match the manual 100%

 

[kubik]

You probably cannot make broad generalisations here. Most of the boards have not specifically designed for this, so it is questionable how well they would be able to supply power to the Pis, which are notoriously picky about their power supplies and cabling. I personally run the Pis in my printers from their motherboards 5V pins, but I had to research to make sure that they would be able to handle it (MKS Robin Nano v1.2 in KP3S, SKR Pico in V0 and SKR v1.4 in one other printer) and I understand what I am doing here

 

[clee]

Currently kit providers such as Formbot are essentially required to include a 5V supply or they risk customers being unhappy because their kit doesn't match the manual 100%

LDO has been opting not to include a 5V power supply in their kits for as long as I can remember (the V0 kit includes the usual 24V->5V step-down converter, and they supply a custom Octopus to RPi power cable for the V2/VT kits). As long as the supplied method of powering everything works and is safe, I don't think anybody will care if they stop supplying a dedicated 5V PSU.

 

[vinnycordeiro]

Also, you need to consider that each case is different: if you are like Timmit and RGB all the things on your printer you definitely want a separate 5V power supply, and maybe even a bigger one.

 

[claudermilk]

I think leaving the option in is probably best for the reasons stated already. I elected to omit the 5V supply and run my Pi off the GPIO, but I also researched the heck out of it to make sure I did it right.

 

[shiftingtech]

I don't know why people are so eager to NOT have a separate supply for their pi.
I greatly prefer having things separate, so that I can keep my pi on, while the main part of the printer is powered down, and I hardly think I'm the only one.

I know the stock voron wiring doesn't quite provide the full functionality that way, but if you have a separate 5v supply, you're just a little bit of tinkering, and maybe an extra switch away from that, whereas without the 5v supply, there's simply no path forward.

 

[mggevaer]

Ah that's an interesting idea.

 

[WhiteWulfe]

Out of the two, my personal preference is a dedicated 5V power supply as in my eyes it's easier to keep any issues at bay. It takes up more room, and requires a little bit more wiring, but on the flipside if there's a power issue you know exactly where to look for the issue. Plus then the Pi basically has it's own power supply.

 

[Outsider]

It’s recommended to supply a RPi4 with a 3A capable source. Are most controllers with a 5V output capable of this, with enough headroom for any other 5V components? Separate 5V supplies seems safer and more flexible to me.

 

[Sanity Agathion]

5V PSU can be used for few other things as well - neopixels (and they can use a lot of power depending on their count), power leads for toolhead boards, and I power 12V fans to undervolt those for silence. Few also opt to keep Pi powered and then use relay to turn on 24/48V supply and rest of the printer.

 

[mggevaer]

@shiftingtech just cost, in a default Voron with the board used in the manual, you'll never need the margin provided by the external 5V psu. It also complicates wiring a bit (just a bit).

It seems that the 5V psu is mostly usefull when you start to mod your Voron, depending on how many people do that, having a separate 5V psu for ALL vorons might be worth it (economies of scale, standardization,...)

 

[claudermilk]

I have my Pi4 running off the Octopus rail. I also have a toolhead PCB, SB LEDs (with Rainbow Barf in the logo), and a string of 36 WS2812B for case lights. All off the Octopus.

 

[DarrylHadfield]

No reason not to use existing power if you have it and have no need for an independent power supply, and are willing to risk the single point of failure.

That said, there is sometimes need for an independent power supply, and some are unwilling to risk the SPOF.

I for one prefer the separate power supply, since it means I can troubleshoot easier ("Did my 5v supply just die? or is it a mosfet issue on the mainboard?")

 

[Outsider]

I have my Pi4 running off the Octopus rail. I also have a toolhead PCB, SB LEDs (with Rainbow Barf in the logo), and a string of 36 WS2812B for case lights. All of the Octopus.

I was curious, it seems the 5V rail on the Octopus board is capable of about 8A. The manual and several other places quote the same figure. So plenty for a RPi. Good to know (I’m waiting on the postman for my V2.4 kit)

 

[120decibell]

The printers are designed to be mostly hardware agnostic. As such, people may choose to use an MCU that doesn't have a big 5V supply which would make the external supply necessary. Personally I'd rather have a BOM that over-includes rather than under-including so if it were up to me it would stay in.

 

[Cosmos]

I say keep it in, it's future proofing and for a self-sourcer like me only cost like £3-5 extra when I bought my MW LRS-250.
we never know what the future may hold & 5v is verrryyyy common for tinkerer-tech devices that may be useful for our 3dp needs.