Tesla Owners Will Soon be Able to ‘Charge on Excess Solar’ from Powerwalls

Tesla will soon let owners of its electric vehicles (EVs) charge their cars using excess solar energy from a Powerwall, allowing them to “drive on sunshine,” as the company puts it.

The information comes from Long Zheng (@longzheng), who pointed out code string changes shared by @Tesla_App_iOS for the as-yet-unreleased feature in the latest version of the Tesla app for iPhone users. While the code for the feature already exists within the Tesla app, it isn’t live just yet.

The Powerwall is Tesla’s residential energy storage solution. It acts as a large battery, storing solar energy generated by your system to use as backup power in the event of a grid outage or other disruption. Last week, Tesla once again started selling the Powerwall standalone, without an accompanying solar product.

Judging by what we can glean from the code, the planned feature will let Powerwall owners juice up their Tesla completely off-grid, with excess solar energy that their Powerwall wouldn’t be able to store.

“Plug in your vehicle at home during the day to charge using the excess clean energy generated by your solar system,” new lines of code in the Tesla app state. “Set your charge limits and location and tell your vehicle when and where to charge only from excess solar.”

The upcoming feature will exclusively use clean energy generated by a solar array to charge your Tesla. That said, Tesla owners will also be able to configure their EV to charge enough for their daily commute using whatever power is available, but only use excess solar energy for the rest.

According to the app, you will be able to “set your vehicle’s battery to charge as usual from any available sources for enough daily driving range. Then reserve part of your vehicle’s battery to charge only when excess solar is available.”

As of late, Tesla has also been letting Powerwall owners in several locations opt-in to virtual power plant (VPP) programs that compensate them for any energy they contribute to the local grid during peak demand.