I’m looking for a power adapter with (4?) USB ports to support multiple pi’s but I can’t find anything that can support more than one 3A pi. I expected there to be loads of options - is there a reason why this can’t be done or do I need to brush up on my google-fu?
That likely has to do with “how many people would want one?”. I ended up making my own from parts and pieces.
The docs say they need 3A so I thought I’d need more than 2.4A? But if you were sucessful, maybe that’s not needed?
i’ll try it a bit later on to double check it for you
Thanks Sir, no rush, just when you get a few mins
The power supplies rated current is the maximum current it can supply. Under normal conditions your Raspberry Pi will be using a lot less than that. Likely less than half of that 2.5A.
Raspberry Pi Documentation - Raspberry Pi Hardware
Start adding things to the USB Ports and GPIO Header and you start using more current.
The Voltage is a constant +5V, the Current varies depending on what the load needs.
My custom power supply is rated for 10A. I have one USB C and 3 Micro USB cables on it. I can power up to 4 Pi’s at once.
I think the discussion about current is only one side to consider. I never managed to reach these 3A claimed by the datasheet.
Much more important is the stability of the voltage. And all those multi-usb chargers fail in this respect. The problem is that they are built as chargers, i.e. with a more or less stable load over (short) time periods.
The current draw of a Pi is totally different. You will have four cores changing from 600MHz to 1.5GHz, and if you have additional peripherals this will also lead to current spikes.
The voltage of these chargers will then drop. I have tested a few of them, and one Pi suddenly requesting more current can result in an other Pi rebooting due to low voltage.
So my suggestion is to better stay away from these chargers.
Ditto, IMHO you want a “Power Supply” not a “Charger”. Mine is a switching power supply.
Ok good shout, yes, it’s a charger I want. I have a couple of pi’s in a stack and adding to them so didn’t want to have a whole 4gang just for those. Not sure there’s a solution to that.
I don’t think you’re going to find an off the shelf solution. I would love to be proved wrong, but as of yet I haven’t seen anything.
I built mine to get rid of the clutter and simplify things. I’m a retired Electronic Technician, wiring / soldering is no big deal for me. I do get that it is an issue for some though.
May I ask what model Pi’s they are? And what task are they doing?
You might want to take a look at GitHub - tomek-szczesny/pistackmon: PiStackMon, the ultimate SBC stack monitor. This pcb was designed with Pi-stacks in mind. There are two versions: the classic version allows easy chaining of the power-input but is two-sided and you have to solder very small components (which are BTW currently not available). The new “lite” version is one-sided only, so you can order it directly (I used JLCPCB), and chaining is also possible but a little fiddly. The pcb uses a large cap to deal with spikes, and it has a polyfuse like the Pi has.
(disclosure: I wrote part of the software for this pcb).
Thanks @alphanumeric. I’m particularly cak-handed which isn’t a problem per se other than aesthetics and I don’t have much in the way of equipment (primarily because I thought I’d only every use it once or twice). TBH I just thought I was missing something - it is surprising to me that whilst there are cases for Pi clusters, the user would need a bank or power supplies; if anyone wants to develop this idea, I’ll be your first customer and only charge 15% commission :-D.
I currently have a Pi2 running pihole, a Pi4 running Kodi, a Pi Zero for a naturecam; I’ve also got a couple of 4’s on order (for ages!) - one for VPN/remote-access and another for other random projects as they come up (including testing things I think some of my nieces/nephews might find interesting). Whilst I could rationalise some of those (PiHole/VPN looks like an obvious candidate), I’d prefer the separation.
Thanks Bablokb, I’ll read that - looks like there’s a lot to read and take in there.
There is this, Dual microB USB Power Cable - Pimoroni
I would think the Pi 2 and Zero can be run from just the one Micro USB power supply.
A Pi 4 and a Pi 2 or Zero will likely be OK too. Youd need a Micro USB to USB C adapter for the Pi 4 though. Trying to run 2 Pi 4’s on one supply would be pushing it IMHO.
I ran a Pi 4B from a Pi 3 Micro USB power supply without issue.
Micro USB to USB-C Adapter - Pimoroni
It’s not ideal, but might remove half the clutter.