Change ADF-Frequency without Battery-Power

Hello! I have been dealing with a problem for 2 weeks that i cannot get
solved. There is an ADF in my plane that works without any problems. But only
as long as the battery is switched on. When the battery is switched off, the
frequency can be set via the ADF, but it is not transferred to the simulator
as the active frequency. If the frequency has been adjusted and the battery is
switched on again, the ADF display no longer corresponds to the frequency set
in the simulator. How can I solve this problem? Is there a way to set the ADF-
frequency as active without power? Or maybe to connect the ADF to the hot
battery bus? I would be very, very grateful if someone could help me with this