Hi Peter, Iam told the RP4 requires a constant 5.1V and 3 A available to run kstars properly without errors. I power my pi using a 5V 2.1A powertech battery jumpstart system and works really well, haven't seen drop-outs yet, I use this to run my entire system mount, cameras, heaters and the Pi . Some powerbanks that I have tested tend to drop voltage below 4.8V when the charge drops below 80% and this affect the RP4 from running or booting properly.
