ORIGINAL: LordArkham
Fuel logistics - this current game is confusing me. I have a lot of gas mines. My small fleet is getting low on fuel. They just finished stomping some pirates and some slugs. I tell them to head to the nearest refuel point - they go to the next discovered system! I couldn't figure that one out.
I've been doing some reading on fuel and mines - ie what's available etc.. I'm hopefully I'll get it figured. Base / Ship Design it seems will have an impact on efficiency.
Why they won't refuel:
You got a 4 ship fleet with 300 fuel capacity each. When they refuel, they want to reserve their full fuel capacity to know that there will be fuel waiting for them. So they reserve 1200 caslon (or hydrogen) (300x4).
On the mine/spaceport/colony there are two numbers in the cargo list. Amt and rsvd or something like that. What happens when a fleet refuels there is that its request for 1200 caslon is added to the reserved amount. The actual free amount is "amt-rsvd". Be aware that even if they only lack 20# fuel or so, they will reserve 1200 (or 300 each) until after refueling.
The fleet will always look for a spot with the 1200 caslon free (unreserved). If they warp off, the closer source does not have enough caslon (not 1200 free). Once it has refueled, it will release its reserved amount, so it could possibly take only 200 of those 1200, and 1000 is available for others afterwards.
The other "reservers" are freighters. When they go for a pickup they will reserve their order.
This means that two large fleets will be reluctant to refuel at the same location, because an incoming fleet reserves a large amount of fuel. And they require a large free amount to go there in the first place. If you have anything remotely close to a fuel shortage, freighters will be aggressive about carrying it "home", and there is never much unreserved fuel on the mines. With a proper shortage, they probably grab fuel in bulks of 30 or so, spending more fuel transporting it "home" than they actually carry...
The way refueling ships reserve the full amount makes sure they will actually be able to fill up, but it also makes it tricky to refuel multiple fleets in the same area. You can control-right click the fuel location with the fleet selected and tell them to "refuel at...", in which case they will go, but if there is not enough fuel as they arrive, only the first ships (if any) will get any fuel apart from fumes.
The advice about bigger fuel tanks seem counter productive. Bigger tanks, means more fuel must be present to actually refuel, and more fuel is reserved by refuelers (also civilian ships). Also, more fuel is lost if the ship is destroyed. Bigger fuel tanks give more range, but it should also give more problems if there is a dodgy fuel situation.
If you are short of fuel in an area, focus on better cargo system to get some capacity on resupply ships, and refuel the military from one of those.