Can you document the CANBIUS interface

[apgodshall]

maybe you could add to the README the canbus interface that this works with, and which specific dev-board it is known to work with?

The ESP32 boards are attractive from a cost and size point of view, and I have tested
using the wifi ESSID as a beacon, it would be clever to show the charge rate and
voltage in a form that any cell phone or tablet can see without an app.