5

My RPi 4 consumes about 0.5A after executing sudo halt, while according to this post it should draw at least an order of magnitude less (0.069A). The green LED blinks several times then goes off, but the device seems to stay powered indefinitely. Notably, the 3.3V pins on the GPIO remain powered, and the LED on the network interface keeps blinking.

This happens of a vanilla Raspbian Buster image with all upgrades installed. The RPi is powered via the USB-C connector. Additionally, it's connected to Ethernet, there's an HDMI screen attached to it, as well as a wireless USB keyboard / mouse. Disconnecting those cables doesn't change the power consumption significantly.

The only hardware modification present on the board is a reset button connected to GLOBAL_EN signal and ground on the J2. Essentially, when the button is not pressed, the board connectivity is not modified in any way. When the GLOBAL_EN signal is grounded, the current drops to 0.15A.

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The Pi4 SHOULD enter a low power state on Halt, but this prevents the power up by pulling pin 5 low.

There is a patch to make it operate the same as earlier models which continue to use power when shutdown. If using this the RUN pin should be used to restart.

The original Buster image works, apparently the Foundation changed later images.

My Pi4 (early 2GB model) running Raspbian Raspberry Pi reference 2019-06-20 vcgencmd bootloader_config shows:-

BOOT_UART=0
WAKE_ON_GPIO=0

I haven't measured current but on poweroff the 3.3V power is off.

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  • Thanks for your answer, I missed it somehow. I will try to update the bootloader config. Especially POWER_OFF_ON_HALT sounds promising. – Dmitry Grigoryev Nov 8 '19 at 14:56
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This has been a source of confusion for some time. About 4 months before you posted your question a "Raspberry Pi Engineer" claimed in this forum post that power consumption would be 3mA (15mW power) following a poweroff command. We're still waiting for this :)

To be fair, there has been some improvement in power consumption since that post, but as of today, with the current "critical" version of the bootloader (Apr 29 2021), it remains an order of magnitude greater than what was claimed more than two years ago. It also requires changing two of the bootloader's parameters from their default values: WAKE_ON_GPIO must be set to 0, and POWER_OFF_ON_HALT must be set to 1.

A couple of "side effects" of this Low Power Mode to be aware of are:

  • The handy "Single Button Start/Stop" feature - enabled with the gpio-shutdown dtoverlay - will no longer work as GLOBAL_EN is required for a re-start.

  • The 3V3 bus is disabled; GLOBAL_EN is pulled up to 5V, and it must be brought LOW, then released, to effect the restart/reboot.

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  • 1
    Thanks for this new info. A difference between 3 and 30 mA is only really relevant for battery-powered applications, and I'm convinced the Pi is a poor choice for those anyway. What surprises me much more is the 500 mA figure which you get if you keep WAKE_ON_GPIO enabled - it suggests the Pi needs a running core and powered RAM just to monitor a pin. – Dmitry Grigoryev Jul 15 at 13:14
  • You are welcome. My "off-grid" project has motivated my effort to minimize RPi power consumption. I chose the RPi knowing that there were better alternatives for power consumption, but that its versatility would prove more useful. While I have to say that my experience with The Foundation's engineering team has been disappointing, they seem to be moving slowly in the right direction.. – Seamus Jul 17 at 5:03

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