Questions About PoE for Radxa Rock 5B+: Compatibility, Power Requirements & HATs

#1

Hey everyone,

Another newbie here trying to power a Rock 5B+ via PoE. According to the documentation, the 5B+ requires around 40W , which is noticeably more than the standard Rock 5B that works fine with 25W .

Regarding IEEE PoE standards, here’s what we have:

  • 802.3af – up to ~15W (definitely not enough)
  • 802.3at (PoE+) – up to 25W
  • 802.3bt (PoE++) – goes above 60W

So clearly, I’ll need a PoE+ or PoE++ compatible switch or injector that can meet the higher power requirements. The issue is, the existing PoE HAT seems to be designed specifically for the Rock 5B and may not be sufficient for the 5B+. On top of that, it’s currently out of stock — so if I manage to get one, I might even need to consider a DIY upgrade.

Since I’m still new to PoE, I had a few questions:

Why isn’t there a more generic PoE HAT or module that can tap into the 4 standard PoE pins and provide higher power output — kind of like how PoE splitters work?
I’ve browsed AliExpress for generic PoE boards, but haven’t had much luck finding anything suitable for this use case.

I also came across these two official Radxa PoE HATs:

They seem to offer similar power specs, so I’m also curious:
Why can’t the same HAT be used across both the X4 and the Rock 5B/5B+? Are there hardware differences (e.g. pin layouts, power delivery paths) that require separate designs?

Any insights or recommendations for powering the Rock 5B+ over PoE — including any community projects, generic solutions, or tips for DIY options — would be super helpful.

Thanks in advance!

#2

Why would Rock 5B+ require 40 watts? The CPU is the same, there aren’t any differences between them significant enough to require 40 watts… I wonder what Radxa says.

#3

Because the board can have two SSDs and a LTE module for sure it will need more power. in List of supported boards for the HAT 5B+ is missing.

#4

…plus built in wifi, ddr5, extra mipi and for some soldered eMMC.
probably bare board would not take so much extra energy, but for sure more is needed with two nvme drives and more ports.

#5

Well, I thought that DDR5 was supposed to be more power efficient. And I doubt you need more than 25W if using just 1 NVME SSD (still, going above 25W is quite difficult on this board)

#6

At same time it should be clocked higher than DDR4 and for sure more power efficient if there is right support. ASAP for now no real performance gain :confused:
My Rock 5B idles at 1.5W with both m.2 slots occupied. On high load I saw up to 14W and I’m sure I can get even more with something in USB ports. Higher estimate for 5B+ seems to be reasonable, that doesn not mean it will not run on previous POE, it would be just easier to hit the limit.