I have written an "intent handler" called
"Nikola" in Python that accepts Alexa requests (called "intents") specific to the Tesla and then acts via the Tesla API.
Nikola currently accepts and answers requests like "How charged is my car?", "How far can I drive?", "How warm/cold is my car?", "What does my odometer read?", and "Is my car locked". It also executes simple commands like "Start charging my car to 90 percent", "Unlock my car for 10 minutes," and "Change my maximum charge to 70 percent."
I must say it's a lot of fun to be around the house and just be able to ask: "Alexa, ask Nikola to charge my car to 75 percent"...and have it just happen.
I've made this code public in GitHub, and I'd imagine it's adaptable to Google Home. At the moment, I'm filling out more complex functionality (like "Get my car ready for a long drive by 9 o'clock tomorrow morning" -- which will charge the car to 100% just before I'm about to depart, as well as checking the internal temperature and warming/cooling the car to within 5 degrees of the climate control setting), and then was going to start working on an IBM Watson Conversation interface. But adapting it to Google Home might be more interesting. If anyone wants to fork my code and do some work on it, I'd encourage that -- much of the hard work is done on interfacing with the car, and this work will continue.
For those so inclined, here is the GitHub repository for the Alexa project:
Nikola: An Alexa Skill for Monitoring and Managing Tesla Automobiles