You're not one of those folk who thinks it's easier to drive somewhere to fill a car, are you?
Why not? Couldn't be any easier, no planning, when it gets low, just pull in and instantly top it up. No need for an enforced break, on route.
I just squeeze the trigger, when full, it stops. No drama, no concerns about 80%, or over draining it, reducing the life.No peering at some numbers on a petrol pump and trying to decide when to let go of the trigger...