Pis require 5+/-0.25v. Current (amperage) not only varies by model, but also depends on attached devices that are powered by the Pi and what the Pi is doing at any given instant. The current specs given for Pis are "worst case". That is, it's the maximum current the Pi will ever use. Therefore, most of the time, a Pi will draw less than maximum current.
The spec for a Pi4B is 5v at up to 3A, so one should use a 5v power supply capable of providing 3A. From what you said, the HAT also requires 5v and will need up to 3A. So if you're going split the power lead between the two, you should use a 5v 6A supply to cover all load configurations.
The power supply specs you give will only provide 2A at 5v which is 10W. The Pi has no way to ask for--and, indeed, can't handle--higher voltage. That the power supply can provide 3+A at a higher voltage doesn't do you any good. Since both devices want a 5v supply, all your unit will deliver is 2A.
Given that you say that in a future configuration, you'll be using a controller that is spec'd for 9v at 3A (which would be 27W), I think your best bet is the get the official RPT PSU for either the Pi4 (5v at 3A) or Pi5 (PD with 5v at 5A, but defaults to 3A) for the Pi, and--assuming that your controller is PD compliant--either the Pi5 PSU which has a 9v 3A mode) or the new RPT 45W PSU for the HATs.
The spec for a Pi4B is 5v at up to 3A, so one should use a 5v power supply capable of providing 3A. From what you said, the HAT also requires 5v and will need up to 3A. So if you're going split the power lead between the two, you should use a 5v 6A supply to cover all load configurations.
The power supply specs you give will only provide 2A at 5v which is 10W. The Pi has no way to ask for--and, indeed, can't handle--higher voltage. That the power supply can provide 3+A at a higher voltage doesn't do you any good. Since both devices want a 5v supply, all your unit will deliver is 2A.
Given that you say that in a future configuration, you'll be using a controller that is spec'd for 9v at 3A (which would be 27W), I think your best bet is the get the official RPT PSU for either the Pi4 (5v at 3A) or Pi5 (PD with 5v at 5A, but defaults to 3A) for the Pi, and--assuming that your controller is PD compliant--either the Pi5 PSU which has a 9v 3A mode) or the new RPT 45W PSU for the HATs.
Statistics: Posted by W. H. Heydt — Fri Jun 13, 2025 3:37 am