In v0.4.0, when charging the power block in Santorini, the text suggests that this is "Super Fast Charging", but it's actually 5x slower instead of 5x faster. This means that the fastest charging method is actually to charge it in your rover while the rover is charging from Santorini, but that causes "finished recharging" message spam that blocks waiting.
You can't recharge the rover at Astrape because of the incompatible power systems. It seems difficult to get to Astrape with the rover and enough spare fuel + power to totally recharge the block; it's such a power-hungry process that I'm not sure a full load of fuel cells is enough.
I hadn't considered trying to partially repair the aircraft to use its power systems, though; does that work?