I usually leave tankers outside fleets in auto, and the ones on defensive fleets too. For offensive fleets I leave them in manual since I want to move them with the fleet when moving through enemy territory to refuel at will, but that is just my preference at this point. Maybe in the late game I get ...

The tankers yellow bar is its own fuel, the one they use to refuel ships is under cargo when you have it selected, and if the ship is on manual control you need to manually load it up and refuel your fleet.

If you leave them in auto in a fleet, they "theoretically" do the same as outside the fleet ...

Well, I guess that then I'll have to build a ton of refuel ships and let them auto refill everything and leave them outside any fleet for that.

Hi, I'm starting to have an issue with private freighters, there are 400+ fregihters in my empire, and when looking into the resources tab I have 700k+ fuel stockpiled, but when I take a look into my spaceports, all have 0 of it, which means that after any battle I have, I cannot repair and refuel ...