Powering 4x 3.5" HDDs separately while using Penta SATA HAT on Raspberry Pi 5

Hardware and peripherals SATA HAT
1

I am referring to the following document:

https://docs.radxa.com/en/accessories/storage/penta-sata-hat/penta-for-rpi5

From the documentation, my understanding is that the Penta SATA HAT can supply power to the HDDs as well, and it also says: “Do not use more than one power supply method at the same time.”

I am planning to build a RAID setup with four 3.5-inch HDDs using the Penta SATA HAT.

My planned configuration is:

  • the 4x 3.5" HDDs are installed in a separate HDD bay/backplane (such as a Rosewill RSV-SATA-Cage-34-type device), and the drives receive power from that bay/backplane

  • the Raspberry Pi 5 is powered separately using a 5V/5A PSU

  • the Penta SATA HAT is used only for SATA data connectivity

In this case, is the configuration valid?

I would like to confirm whether using:

  • separate power for the HDDs, and

  • separate 5V/5A power for the Raspberry Pi 5

is acceptable when using the Penta SATA HAT, or whether this could cause any power conflict or back-powering issue.

Any clarification would be appreciated.

2

Although the connectors are for HDD’s are 1 piece of plastic, the signalling part is separated from the powering part. So as normal for at least 3.5inch HDD’s, it is easy to use separate cables. The wires for power (red, black, black, yellow) are easy to re-route, connect somewhere else. As long as you keep a common-GND or floating/isolated mains PSU, it is no problem to do separate powering. It might be that sequential powering on like know from Helios in order to peak startup power won’t work, but as far as I know this is anyhow not implemented in the 5-HAT.

There is no back-powering like can happen for USB only connected devices with a externally powered hub. As you separate the power wires yourself, what is not the case with USB, unless you rip the USB cables apart and interrupt/cut Vbus wire. Also the SATA chip itself gets power from the Pi5 object.