[emoji3516] I'm surely not an expert...however, to achieve your concern as you describe it, and I interpret it.
All you would have to do is simply leave the key in the ignition. You see the car charges the key while the key is inserted in the ignition...even when the car(engine) is off. Of course make sure the car is in a secure place...(thieves). This works well for you seeing you don't drive the car much![emoji2958]
No need to build a better mouse trap!