I booked my tim car for two hours but now only need it for one hour. Can I return it earlier?

Of course. Just terminate your booking using the “Current Trip” (“Aktuelle Fahrt”) function. You will then only be charged for the hour(s) that you actually used.

tim charging situation is changed
The tim card is no longer a charging card since 01 March. To charge the car sharing vehicles, a charging card can be found in the respective vehicle. You can find more information about this in the article.