ROCKPro64 Battery Power Supply

[nano2]

I could find no good information on the actual current use of the rockpro64, so here are measurements i made:
I built a 12V 3A power supply - mains transformer, not swithcing. The no-load output was 17V

power use:  ~17V input,  with fan installed USB keyboard +usb mouse, no network;  cheap digitech DVM
    initial early boot pre-X    0.3A fan off
    during boot to X            0.65A  fan running
    static X interface          0.4A        "
    open firefox                0.8A        "
    ====

USING 5V 2A switchmode plugpak = 5.2V :  boot fails  GPIO pin 2 is 4.5V (instead of 5V),  pin 1=3.3V - OK
Use bench power supply (linear regulated)  5.5V - boot fails
Use  bench power supply 6.0V: boot succeeds  with wired enet , fan running, emmc xfce4, USB key & mouse
              GPIO pin 2 is 5.2V ;   I did not measure pin 1 - it must be OK
               Current measured on Tektronix DVM:     during boot has 1.3A peak;  
                                0.5A with peaks to 0.6A with idlle xfce4 display, no apps running
                                Starting Fifrefox:   peaks to 1.7A, static page display 0.6A
                              Real peak currents will exceed this briefly due to DVM averaging and read intervals
If you are not using add-on devices or the PCI interface it seems you can run on 6VDC.