How to make the device work only from the charger?

Question

Headset

There is a Sony sbh20 headset.
Used in the car to play music via Bluetooth.
I would like it to connect to the phone when the ignition is turned on.
To do this is quite simple - you need to make it turn on with the ignition.
The simplest thing is to prohibit her from using the battery and then when the ignition is turned on, current will be supplied to the charger port, the headset will turn on and search for the phone.
Question: how to do it correctly so that it remains operational and works in this mode?

Answer 1

Alternatively, disassemble and disconnect the battery.

Answer 2

The issue can be resolved in a different way. Through auto-connection via Bluetooth with the help of a program in the phone. The required program can be easily found on the market.

Answer 3

Thanks for the advice, I solved the problem by buying a car with a built-in bluetooth module.