Power Saving

Disable WiFi and Bluetooth

Open the config.txt file located on the boot partition,

sudo nano /boot/firmware/config.txt

and add the following two lines below the [all] section at the bottom of the file.

dtoverlay=disable-wifi
dtoverlay=disable-bt

Reboot the Raspberry Pi

sudo reboot

Raspberry Pi Headless Power Saving

To disable HDMI, edit rc.local

sudo nano /etc/rc.local

and add the following line above exit 0.

/usr/bin/tvservice -o