V2H is when an electric car powers the home; V2G is when it sends energy to the grid. A bidirectional charging station can not only charge the car but also draw energy from it: the battery on wheels becomes a home backup for several days. The car is charged when energy is cheaper, and in the evening peak hours the home runs on it.
How it works
The car’s battery stores direct current, while the home runs on alternating current. An ordinary charging station pushes energy one way — from the grid into the car. A bidirectional system has an inverter — in the station or in the car itself — that can also do the reverse: it takes direct current from the battery and supplies the home with alternating current at the same voltage and frequency as the grid. The car and the station talk constantly over the cable: how much energy can be taken and when to stop.
When the power goes out in the neighborhood, an automatic transfer switch disconnects the home from the outside grid so the car’s energy does not flow into the lines where electricians may be working. The home switches over to the car: the fridge, lights, pump and boiler keep running. When the grid comes back, the switch reconnects the home, and the station starts charging the battery again. How long the car lasts depends on the load: the fridge and lights use little, an electric stove and air conditioner use a lot.
In the app you set a minimum charge level — how much to keep for the morning drive — and the station will not discharge the battery below it. Beyond that it works with the tariff: it charges the car at night or by day from solar panels, and in the evening, when energy costs more, sends it to the home. In V2G mode the grid company manages the same thing: many cars together act as a distributed power plant at peak hours.
Where it already works
- China, Hubei: cars fed 376 MWh into the grid over 21,000 discharges (August 2025 — March 2026).
- Private homes with an electric car: an energy reserve in case of outages.
- Homes with solar panels: by day energy builds up in the car, in the evening it goes to the home.
- Grid companies: cars smooth out the evening demand peak.
What to consider
- Not every car can give energy back: check that both the car model and the station are V2H-capable.
- Check the battery warranty terms: the manufacturer may count extra discharge cycles separately.
- Connecting to the home is an electrician’s job: you need a switch that cuts the home off from the grid during an outage.
- Selling energy to the grid (V2G) requires a contract with the grid company — at home it is simpler to start with V2H.