Not at all sure I'd consider having to lug heavy batteries out of the
glider,
putting them in a car, transporting them and then recharging them in
your RV/Gite/hotel/hangar/caravan/whatever could be viewed as a
universally good solution.
Then reversing the process next morning?

Simply plugging a single mains power lead into the Antares type 'battery
in wing' is a bit simpler, no? (The Antares has a built in charger system).

Plus if the whole shooting match bursts into flames it's not in your
RV/car/hotel/Gite......

Some European gliding clubs even now do not allow electric gliders to be
charged in their club hangars: fire risk, insurance problems?

Interesting times.