While the car didn't show it directly, the my.chevrolet.com website used to allow you to download this data from OnStar. I believe it listed each charging session and kWh used. Unfortunately, with the latest website revision, they simplified the UI and removed the ability to download any data.
The JuicePlug might be able to do what you're attempting, once it comes out.
You might also call the GM Connections Center at (877) 558-8352 and ask them to bring back the ability to download charging data from the website. I doubt it will do any good, but maybe they'll at least realize people still want access to this data.
Good luck! If you come up with an easy solution, be sure to post about what you did.
The JuicePlug might be able to do what you're attempting, once it comes out.
You might also call the GM Connections Center at (877) 558-8352 and ask them to bring back the ability to download charging data from the website. I doubt it will do any good, but maybe they'll at least realize people still want access to this data.
Good luck! If you come up with an easy solution, be sure to post about what you did.
