Visited on July 29 without charging.
The charger is in the parking in front of the shop. Other parking spaces nearby are indicated "Nur für Kunden" of "Duftoase - Am Bach 16" and "MAHE Herrmann - Am Bach 19", but the charger having its own sign and paint, it seems to be open to anyone.
My GPS seemed to think I had to go through Sossaugasse to access Am Bach, but that's not required, and seems in fact more complicated. You can turn on Am Bach directly from the main road and drive on the small bridge to access this area.