Vehicle-to-Home

Vehicle-to-home, abbreviated V2H, allows an electric vehicle to supply electricity from its traction battery to a house, turning the car into a large reserve of energy for the building. Where an ordinary EV only consumes power, a V2H-capable car can reverse the flow and feed a home's lighting, appliances and heating. Because a typical EV battery holds far more energy than a dedicated domestic storage unit, this transforms the vehicle into one of the most substantial home batteries most households could own.

The two principal uses are backup and energy shifting. As a backup supply, V2H comes into its own during a power cut: the system isolates the home from the failed grid and runs essential, or even all, household circuits from the car. A medium-sized EV battery of 60 to 80 kWh can sustain a frugal household for several days, far longer than a conventional standby battery and without the noise or fuel of a generator. As an energy-shifting tool, V2H lets a household charge the car cheaply overnight, or fill it from rooftop solar during the day, and then draw that stored energy back in the expensive evening peak, lowering bills and making better use of self-generated renewable power.

Delivering this requires more than a special cable. A bidirectional charger inverts the battery's direct current into mains-grade alternating current, and a transfer or changeover device safely disconnects the property from the grid before the car begins to supply it. That isolation is essential for safety, since exporting power onto lines that engineers may believe to be dead would be dangerous. The installation usually involves a qualified electrician, an upgraded consumer unit and integration with any solar inverter and home energy management system already present.

The car itself must support the function. Not every EV permits battery export, and among those that do the implementations differ, with some confined to vehicle-to-load or grid services rather than whole-home supply. Early V2H deployments were associated with the CHAdeMO DC standard, which defined bidirectional operation relatively early, though AC-based and CCS bidirectional approaches are now broadening the range of compatible models. Owners must check that their specific car, charger and household configuration are mutually compatible.

A few practical considerations temper the appeal. Whatever energy is sent to the house is unavailable for driving, so most systems let the owner reserve a minimum charge for mobility. The hardware costs more than a standard wallbox, and the economic case depends on the gap between cheap and peak electricity prices. There is also the question of battery wear, although modest daily cycling generally has limited effect. V2H sits between the grid-connected ambitions of vehicle-to-grid and the simple device-powering of vehicle-to-load, all built on the same high-voltage battery, and it offers households a compelling blend of resilience and cost control.