Power Rock 5B+ GPIO, PoE pins, or both?

Hi all,

First time posting, but I’ve been reading a good bit as I set up my Rock 5B+. I am planning to use it as an embedded renderer for HQPlayer - an audio oversampling software. It is very computationally intensive, and the 5B+ will likely be pushed fairly hard while running it. I am hoping to be able to run it on battery when travelling and to be able to move it from room to room. It would be headless with input via USB OTG from phone and output to a portable DAC / AMP like a Mojo 2 or Tube Mini.

I’m trying to decide if it is best to power it through the 5V GPIO or with 12V on the PoE header (if that is possible).

I am planning to use it with the Geekworm X-UPS1:

I have been limited in my testing so far, as HQPlayer is only recognizing the A55 cores at the moment. I’ve been working with the dev to gather info on the system, and he is confident that by the next release he will have it running on the full CPU. I tested the Rock 5B+ with a Geekworm X1202 that I have for my RPi 5, and I connected the two +5V GPIO and the two grounds to 2 of the 5V XH2.54 outlets, and it was able to run and execute software updates that utilized all 8 cores, and it passed the “stress” command test on 8 cores for 60 seconds several times without rebooting. I’m not sure if that is particularly representative testing, but at least it was encouraging.

The battery I’m planning to use appears to output up to 3A regardless of voltage and has 2 connections each for 5V and 12V. I would assume that 5V 3A is not going to be enough to power the 5B+ sufficiently, and I’m not sure if it will split the current if I connect both 5V connectors and just do 1.5A through each or if it can do 3A through each for 6A total. I also am not sure if that would be enough power. I know 40W is recommended for Rock 5B+ power supplies.

I have not been able to find the pinout of the PoE header on the board, but I was under the impression that it could handle 12V, and if I connected both connectors, even if it is splitting 3A between the two, 36W is very close to 40, and the connected devices (phone on OTG and DAC/Amp on USB host port) would have their own battery power (though I suppose I might try it at some point with a dongle DAC/Amp that could use up to 4.5W max, but typically more like 1.5-2W). WiFi would also be active, just for remote configuration, but throughput will be minimal - data will be coming primarily from USB. I also have an NVME drive installed that uses about 4W max, but typically much less, and it will be under a very light load, it’s mostly just for initially loading the software, though if this would be a big increase to the overall power usage, I could swap it for an SD card. Finally, I have the Radxa branded heatsink with cooling fan on the CPU, but I would guess the power drawn by that fan is quite small.

My questions are:

  1. Is it possible to use the PoE header with 12V output from a battery pack (if so, I would need to know which pins are positive and negative)?

  2. If I can’t use the PoE header, would the GPIO likely adequate with 15 or maybe 30 W for this use case?

  3. Would it be desirable to connect both the PoE header to 12V and the GPIO to 5V? The battery pack is capable of simultaneous output of both voltages.

  4. Any idea what the max power usage of just the CPU would be under near 100% sustained all-core workload? What about the power usage of the USB controllers and WiFi? It would be good to be able to estimate power needs as I consider size / weight considerations for batteries vs run time. This will be a headless installation with no display and no desktop software, so HDMI should not be drawing any power.

Sorry for the long post! I appreciate any insight you can provide. I’m a big fan of the 5B+ so far! It’s a beast of a system, and I’m really excited to see what it is capable of with this demanding program…

Which cores does it run on (numbers)? Are you sure it’s A55? The A76 cores are numbered 4-7, the A55 are 0-3. You can also try taking the A55 cores offline or pinning the process.