I'm making a NAS with a Pi 4B, powered by a Meanwell RS-25 (5v 5a) psu. However, as far as I know, the Pi can only be powered via USB C, but the problem is all my breakout boards are limited to 500ma. The Pi needs to be able to draw at least 3 amps since a hard drive will be directly connected to it.
Are there any workarounds I can use or am I stuck with a generic USB brick?
"However, as far as I know, the Pi can only be powered via USB C" "The Pi needs to be able to draw at least 3 amps" - I wonder where people get these alternate facts or why they choose to believe them rather than the official documentation.
It is certainly possible; I run most of my Pi from a single supply.
That is not to say there are not issues; first adequate power supply, adequate cabling, reliable connections, availability of suitable connectors etc. and the ability to construct the cabling, but it is possible.
No matter the power source, getting the Pi to power external HDD is challenging (the performance of the Pi USB power is underwhelming), and it best done with a powered drive or hub (and in this case finding a suitable hub is itself a challenge).
You are stuck with a brick if you want a realilable system. You state you are planning on building a NAS (Network Area Server) all the drive(s) also need power, how are you going to supply that? Look at using an external powered hub (brick) that can supply the necessary power, it also offers protection to the Pi. You did not state where 500mA limit comes from so I cannot evaluate that part. Each device will draw what it needs until power is no longer available typically because the power supply is undersized as it appears you will be. You have a good power supply but it has ratings for a reason. You might want to check the Pi and its current limit protection, it can only pass so much, that varies by model. If it is a fuse as most are you really do not want to push it to that limit.
I would use these 5A from your PSU and use 2 connectors: 1 to Pi and 1 to the NAS. Directly from PSU to NAS. Otherwise you will spend a lot of time trying to find why the NAS/Pi have issues.
