RPI3B+ disable HDMI

[Stefan Parvu]

Hi,

We have started now testing our product using FreeBSD 12.2 on RPI3 and 3B+. 

I have a question how one can start to disable things from the board which are not needed, to save as much as possible power. For example starting with HDMI port. I am trying to do some basic tests running our data recorders with FreeBSD 12.2 only on batteries. (4 x 18650 Li-ion 3500 mAh). Would it boot from batteries. Has anyone tried before this?

Thanks,
Stefan