That sounds like a plan! 
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When you are using this type of power supplies, how do you enclose them? The 230V terminals are exposed as is, and it isn’t really safe?
I’ll put them in a DIY wodden crate. Go to the local DIY, buy a bunch of multiplex boards or something, cut them properly and put the power supply in - either make some holes in it or use perforated sheets to let air flow through.
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I 3D printed a case that would fit into my 6inch rack but if you are worried about high voltage another solution is to buy a standard PC psu, think they give 10-15A and up on 5V. Another nice thing with them is that you get 12V in case you want to connect a fan a switch or other equipment requiring the higher voltage.
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Actually, the 230v terminals are usually (like the rest of the terminals) behind a cover and if you “mount” the wires correctly, it is quite a feat to get an electric shock. To @binderth and @John_Galt point, you can also put the power supply in a cover and or use a PC power supply. Although a PC power supply is a bit bulkier.
I’m in the process of replacing the power supply mentioned in my post with a 12v power supply to be able to hook up a 12v fan for cooling instead of relying of the small 5v 40mm fans. Then I’ll use a buck converter to get from 12v to the 5v that my PI’s require.
@bdollerup for my 12V fan I use a https://www.electrokit.com/produkt/dc-dc-omvandlare-step-up-1-25-35v-3a/ (or similar) instead, figured it would be cheaper and less heat dissipation to only step up once instead of step down for all Pi’s. Also it gives me the ability to control the speed of the fan by changing the voltage on the booster.
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Oh. I do the same. Presently, I have a 5V power supply connected to the 10 USB type A’s. The PI’s plug into the USB connector and thus I also take advantage of the power regulation/protection that the PI support on its USB connection. BTW: You will not get the same protection when you plug 5v directly to the GPIO.
The next version as I mentioned before will have a 12v power supply with this converter:
The 5v out will then be connected to the 10 USB type A connectors. And I will likely drive a fan or two off the 12v connector on the power supply.
I don’t see why you are getting a 12V supply when powering multiple 5Vs and a single or 2 12Vs. Isn’t it easier to get a 5V supply and step up converter for the 12vs?
Reason I’m asking because I’m also about to look over my rack power supply. Currently using 5 x 5V Rpi chargers (taking up a lot of outlets).
Well, I wasn’t thinking 
Maybe I need to send back the 12v and get a step-up instead as suggested by @John_Galt in his post… Either way, powering Pi’s using a real power supply (PC or otherwise) will cut down on the number of outlets you have the use and give you the correct power.
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@bdollerup saw the link above and I concur with Seaside that you actually have a really nice power supply there, and as I said, with a step up converter you can always alter the fan speed by adjusting the voltage, it is tougher to do that if you use the 12V to power the Pi’s as well.
Your comment regarding the lack of power protection when using GPIO pins is true and should be considered when connecting, on the other hand, these PSU’s seem a lot more stable than the flaky chargers that exist for mobile phones so I am willing to take that risk (famous last words…) but there is a risk to burn the Pi.
My only problem now is that the rack I built can only handle 4 Pi’s, time to build a new one
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What kind of rack/case are you using?
@bdollerup I am using a modified version of KronBjorn’s design on Thingiverse, https://www.thingiverse.com/thing:2084736 , but, since his construction required a lot of screws, think 14/Pi, I remade them with only a lid plus some other small things but haven’t uploaded my modifications to thingiverse yet.
For the rack I printed out 4 20x20 profiles, can’t remember the exact ones but similar to these: https://www.thingiverse.com/thing:884966
I have also created a box for the PSU but I am not really happy with it yet so it is not uploaded as well.
One thing to watch out for are the USB cables, more specifically their cable diameter. Most cheap USB cables will not have the wire gauge to support greater current without significantly increasing the voltage drop.
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Hi! I’d be really pleased if someone recommends me how to power this cluster:
It contains:
- 2 Rpi3 B
- 1 Rpi3 B+
- 1 Rpi4 B
The thing is that I don’t have any tool or skill to build my own solution using a PDU from a PC, like some people have shown above. I would like to buy something that isn’t too bulky, as cheap as possible, with enough ports and power.
Big thanks in advance!
I bought two of these for 10 euro each off eBay. Maybe overkill but have been running them fine for 6 months.
I use a power strip like this to power my raspberry pi stack https://amzn.to/30M8ggt
The manager node in the black case is using an official pi power supply since it has a SSD for its drive. Stay away from “smart” USB ports for power
Most - if not all? - those Power Strips use a max Amp solution, so that all usb ports share a maximum of in this case 2.4A. Dob you use it with Raspberry Pi 4s? The 4s use up to 1.2A if all four cores are busy. And if you’re running 4 USB devices they receive an average of 0.6A each, which is enough to feed only idle RPi4s. If one core is busy, it’ll ask for around 0.8A. Did you check the Pis for having enough power?
I was having a problem with voltage dropping with a multi-port USB charger meant for phones, tablets, etc… so I switched to a power strip with USB ports. My Pi’s are overclocked, have a USB drive plugged in and have the LED strip running off of the GPIO connector. The Stack consists of 2 2GB raspberry 4B’s and 2 8GB raspberry pi 4B’s. The manager node in the case has a 2.5 inch SSD connected so that is running off of an official pi power supply