Tried to visit on June 22, but the parking was closed.
I only noticed the parking was not accessible once in front of the gate. Because the sign at the entrance said "frei", I tought it was a ticket gate. But in fact it's a manual gate they probably lower down after closing time.
I assume there's a parking meter somewhere inside.
There's an EV sign on the wall after the gate, indicating the charger is somewhere to the right.