Neat idea! They can be charged on a giant hydrogen balloon platform, which can pump the SO2 to about 20km. I started making pictures of a related concept.
https://docs.google.com/presentation/d/1r6CPFJ1AX1ZULacguTf6...
Just make geodesic cellular kites[1]. Above a certain surface area/mass ratio it becomes difficult not to fly. Power with Magnus effect pontoons[2]. One of the things I'd like to do eventually is make flying buildings that never land.
[1] https://duckduckgo.com/?q=alexander+bell+kites&t=ffcm&atb=v6...
[2] https://newatlas.com/magenn-mars-floating-wind-generator/111...
But the vision seems cool. The battery doesn't have to be big. As long as it can charge fast, and is long lived, it can keep delivering power & energy, coming back down, charging, & doing it again. Persistence.