Other projects • Re: Reduce power consumption of Pi 5

You could try reducing the idle clock speed:

Code:

arm_freq_min=500gpu_freq_min=500

For some reason the default idle clock speed for the Pi 5 is 1500MHz. Reducing it to 500MHz or less saves a little power.

Thank you , it seems to reduce it from 2.7 W to 2.0 W. Somehow the same modification has no effect on power consumption for my iso (comes from the same lite os but with additionnal software on it) but good to know thank you.
On the stock lite image (after installing libcamera-apps) the power consumption rises to 3.7W when using the HQ camera (even with your 500 modification on /boot/firmware/config.txt ), so 1.7W additional for the camera. Seems a lot too, I will need to investigate this.

If your main use-case is camera (streaming?) every now and then and you want low (average) power consumption, a Pi5 is a bad choice. RPi5 has no media encoders in HW, so that has to be done by the big Cortex-A76 cores. And the camera is attached to a companion chip (RP1) that connects via off-chip busses to the main Broadcom SoC, that does not help in achieving low power. There are simple Cortex-A7 (32-bit) devices available with HW encoders, RJ45 and more that are similar size as Pi0. Pi0 with old camera stack can be low power, I have not measured, but you need to solder some RJ45 (I have done that). But for HQ cam you cannot use old stack then Pi0 is not fast enough for higher resolutions,FPS. How often the cam is active also matters maybe, you could simply power off via PoE or so when not needed.

I did not want to « pollute » the question about power consumption (that can benefit many) with my specific use-case but here it is :

I build (3d print) an outdoor camera with a battery (cf picture below ). I developped a web interface (django) that can let you stream what the camera is seeing (to make sure it is well-positionned) and schedule a recording in the future. It records video in h264 format (that I can convert to h265 on my PC later – thank you ethernet cable - in order to take the least amount of energy from the pi – I have a big 256GB SD card so no problem). That scheduling schedules on/off too so that the pi is not running when it doesn’t film. I can swap between camera module 3 and camera hq (and others).

I used to use a raspberry pi 3/4 with a wittyPi4 board for it. The issue is that it was not very reliable, 1/3 of those wittypi4 boards had random failures after a year, and you needed to solder yourself connectors (for button, power etc) on the wittyPi4 board to get reliable contact. I love that the Pi5 has native on/off scheduling capabilities, and is so much more reliable so far ! But the drawback seems to be higher consumption (for same workload as pi 3/4 !).

I even suspect that running the same video capture adds more power draw on a pi5 that on a pi4/3, but I would need to measure it to be sure.

Statistics: Posted by hqcamuser — Fri Feb 21, 2025 1:40 pm

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