Raspberry Pi 5, DC-DC Buck down power supply from 36v, best method?

@davee, and @zander

    I got 2 of these boards, and had installed them on 2 Raspberry Pi 5's.  I've connected a non-Raspberry Pi 5 power supply to the USB-C power input to the board (and the output is connected to the Pi).  I do NOT get a under powered supply warning.   When I connected the non-raspberry pi 5 power supply directly to the pi, I DO get the under powered supply warning.  

     The 'point is' you can use a non-raspberry pi 5 power supply to power the raspberry pi 5, by either a different USB-C supply 'OR' another standard power supply of '9-24V' using the DC power connector.

     I'm wondering if I can use the headers instead of the connector, that would make it super easy to connect.  As it does have headers, but no data on what they are connected to.

     I used a Baseus 100W USB-C wall wort for this.  Next is to use a DC 12V, 12A supply and connect to both of the Pi's. and then connect 4 Pi's (means I need 2 more boards!!!). Then double that, and I got my cluster!!!

     For a AC powered system this looks like what I wanted, but for a remote system, I would be concerned about the efficiency and how much energy is used in the conversion to power this.

@fvasquez1776 Good luck.

Hi @fvasquez1776,

  I don't have any of the hardware you are discussing, but I am trying to make sense of what I can see on web, which (as I said), was the basis of my previous messages, which presents added limitations.

So sorry, I am not clear what you are proposing when you say:

I'm wondering if I can use the headers instead of the connector, that would make it super easy to connect. As it does have headers, but no data on what they are connected to.

Perhaps sketch(es) and/or photo(s) would clarify exactly which connectors and headers you are referring to, as there are several scattered over the different units, so I can try to visualise the whole system.

Best wishes, Dave

@davee

Photo....

lower from the 52PI brand logo.  I'm checking if the pins there connect to the DC connector.  I'm not a fan of adapters to adapters... Link: https://thepihut.com/products/pd-power-extension-board-for-raspberry-pi-5

Vin header holes, for a 2x2 100 mill centers header.

@fvasquez1776 Technically a very nice board, but very pricey. Are you sure you can't make your own version of this for 1/4 - 1/2 the price? I bet I know somebody who could design it.

@davee and @zanker,

     The reason is now known why you cannot connect the USB-C and the input DC power connector at the same time.  It is because the DC power connector, USB-C connector, and the VIN 2X2 100 mill centers header (header not populated) are connected together verified via DVM. Darn I wish 52PI would provide schematics and BOM's. 

@zander

     (sorry used zanker last time... my bad for sure... I have an excuse, i'm off zanker road in San Jose...LOL)

      Agreed, a very nice board indeed.  It really has all the bells an whistles that I think I would need.  A power plug for 5V and a power plug for 5V and 12V (12V is Vin) PC 'style', so I would be had pressed to beat $20 in the effort and the materials needed.

@fvasquez1776 Now that I think about it a bit more I am inclined to agree. If I ever have a use for my Pi5 (worst Pi yet) and power is an issue, I have book marked this board.

@zander,

      I wouldn't think of it being the worst pi yet.  The 'bugs' are being worked out.  The biggest plus it has going for it is the PCI-e bus, and that is still under development.  The PD 'thing' is an nuisance, but not an issue especially since I do know of a work around.  I'll get this solved and my cluster going, and I might figure out how to do the PD comm without this board.  But before that (and after this cluster) I am going to get the color organ thing going...

@fvasquez1776 By worst, I meant the price. Remember the whole point of the enterprise was to allow less privileged kids to experience a SBC. The price for a Pi5 especialy after adding the SSD it really needs, is approaching what I can get a real computer for (used)

I am not the only one to think they have lost their way. Going public is another bad sign, now their focus must be to the shareholders if not they will be seeing the inside of a courtroom very fast.

For guys like us with the financial resources, it is mildly cool tech. I am waiting for a Pi500, if it is good enough it will becoe my new Pi workstation. I expect it wil be announced in time for Xmas.

@fvasquez1776 I heard unofficially you can bump the PCI bus one notch. I haven't done that yet but I will hopefully get around to it eventually.

@davee and @zander,

      OK, I got ants in my pants and had to try the two out...

different view....

both works, boots up fine and no under power message.

The 'boards' in the middle are the Nvme 500GB (boot) drive and pci-e adapter board.  I was looking for my smaller spacers that I had 'somewhere', so I used double-sided foam tape (tape and bailing wire... yessss).  So this proof of concept is ready for prime time.  The cluster will be 7-8 boards, using three (or 4) 12V, 15-20A power supplies.

I was also experimenting with the pci-e, and able to enumerate quite a few things...

Best,

Frank

@zander 

    Done that too already... the 500GB drives are already configured to go 'fast'.

@zander

Here's the instructions...(credit goes to Pimironi)

It's the

dtparam=pciex1_gen=3

Command, near the end, inserted into the config file...

Best,

Frank

@fvasquez1776 I don't like the look of the VIN wires, seem small, and need strain relief. Can't you use the jack?