One enterprising Tesla owner hacked together a homegrown solution to charge his Tesla only when his rooftop solar system is producing energy, allowing him to drive on sunshine.
To do this, he tapped into the capability of the Tesla Wall Connector, allowing it to run in “servant” mode. This mode is meant to allow owners with two wall connectors to have them share a single circuit and regulate their combined current draw. This is done by putting the second wall connector in servant mode, where it then looks to the “master” wall connector to determine how much power it can draw.
This is done by setting a dial inside of the Tesla wall connector and connecting up the built-in RS485 control bus. The two wall connectors can then talk across the RS485 bus.
YouTuber CWNE88 tapped into the functionality of the RS485 bus, which had already been explored quite extensively, and rolled his own version of a controller in the form of a Raspberry Pi, which is essentially just a super compact computer that can run a variety of operating systems and be used for a number of fun projects.
The end result is a nice little controller that runs off of the Pi and talks to his home Tesla Powerwall to determine how much solar is being generated. Armed with this information, the Pi is then able to dynamically set the charging speed of the Tesla wall connector to match the output from the solar system.
The system he created presets all of this information to the homeowner via nice little web front end that allows him to manually select a charging speed, select “green charging,” or even to turn charging off completely.
I love just how much fun people are having exploring ways to create the future they want to live in, today. Tesla’s smart devices are enabling much of this functionality in ways that I’m sure we’ll see rolled into its products in the future as Tesla continues to integrate all of its products across its energy storage, solar production, and automotive product lines.
Check out the video below and the description below the video (on YouTube) to learn more about the build and the code.