MTFCA Forum

USB is useful these days and stepping up the voltage to 12V to step it down to 5V I has always seen as less efficient. I have experimented with various cigarettelighter plugs with USB sockets and actually found one or two that can charge my phone or at least keep up with the consumption when using the GPS. Remember that the voltage on a running model T will be 7,2 - 7,7 volts.
But since the voltage in USB is 5,0volts it ought to be possible to step it down from 6 - 7,5 volt to a stabilized 5,0 Volts. Do you have some circuitry to share?
The bluetooth I find a little ridiculous as the noise level when driving make it rather useless and for music or radio when standing for example at a show - a loos Bluetooth speaker can do.

In response to a USB/Bluetooth question. You can show a picture of this and explain that Tony Stark's (Iron Man) first prototype for an "arc reactor". It was not nuclear based but used a smaller version of a Model T Magneto to act as a magnetic shield to repel the shrapnel in his body from entering his vital organs and blood stream.

https://youtu.be/O2q2ndf7jmY?si=mMCTzfVGpdB7kW12. Paul shins video on cell phone installation in a Model. A. Model T installation is the same, just reverse the wires because the Model T is a negative ground system and the model A is a positive ground system.