Tesla has extended Powershare Home Backup to its two volume cars: certain Model 3 and Model Y vehicles can now keep a house powered during an outage. Previously the feature was exclusive to the Cybertruck.
There are strings attached. Using the car to back up a home requires Tesla's Powerwall 3 battery as a buffer; support for the Powerwall 2 and Powerwall Plus is "coming soon", the company says. The Powerwall is what feeds energy from the vehicle's pack into the house, a design pattern other automakers also use because it separates the car's expensive bidirectional charging hardware from the home's grid connection.
According to Tesla, a Model 3 or Model Y in Premium or Performance trim extends home backup to over two days. For the Cybertruck, the company claims more than three days.
Not every car qualifies
As Electrek first reported, Tesla is only guaranteeing the feature on Model 3 and Model Y vehicles ordered from 1 October onward, because not all older cars include the PCS2 Lite inverter the system needs. The feature is also listed only for the United States and Puerto Rico, not Canada, and not for the larger Model S or Model X. Powershare Grid Support, which lets the vehicle export power to the grid rather than just support the house, remains Cybertruck-only.
Why it matters
Tesla is neither the first nor the only automaker with bidirectional charging. Kia and GM offer vehicle-to-home power too, and Nissan's Leaf offered power-to-grid years ago. What is new is the scale: the Model 3 and Model Y are Tesla's best-selling vehicles, and a fleet of millions of them is a far larger pool of home storage than a niche platform like the Cybertruck.
The customer argument is blunt. A home battery with roughly 13.5 kWh of capacity costs several thousand dollars, while a Model 3 or Model Y with 50 to more than 80 kWh of usable capacity is already sitting in the driveway when the lights go out. For Tesla the incentive is different: home backup ties car, Powerwall and Wall Connector into an ecosystem that is harder to leave — and the Powerwall is the product being sold along the way.
Open questions
Anyone driving an older car is shut out for now. The Powerwall 3 requirement means the feature also demands an upgrade for a large share of Tesla's customers. And because grid-connection rules decide what a car is allowed to feed into the network, the expansion outside North America is likely to arrive more slowly than the announcement suggests.
