Vehicle to Home (V2H): What is it and how does it work?

Power your house with your electric car
Vehicle to home V2H

Electric cars have huge battery packs that can power a house for several days, or even a whole week. This technology is called Vehicle to Home (V2H).

The maths is simple – UK households consume on average between 8kWh and 10kWh per day, a paltry amount compared to the capacity of most electric car batteries.

For instance, the Vauxhall Corsa-e has a 50kWh battery. If your house uses 10kWh per day, then this diminutive electric car will give you five days of power.

Why would you want to do this? The obvious reason is to move off-grid and beat rising energy costs. You could charge your car for free at a supermarket, or for very little on an EV tariff, and run your house off your car battery for peanuts.

Unlike a Tesla Powerwall, which acts as fixed local energy storage for your house (usually for solar charging), V2H uses your car battery for power.  

Another way of looking at V2H is as a supplementary power source to the grid which can reduce your consumption of virgin electricity.

How does V2H work ?

V2H works by transferring power from your electric car battery to your distribution board or an energy storage system like the Tesla Powerwall.

When V2H feeds your distribution board, power is sent to appliances, sockets and devices, with load management to control the distribution.

When V2H feeds an energy storage system, power is sent to a large battery back built into your home that stores energy for distribution later.

Can I power my house with my electric car?

An electric car can power your home, but only if it has bi-directional charging and you have a smart charger with bi-directional charging.

While V2H technology has clear benefits, there are few electric cars on the market today with bi-directional charging to accommodate it.

Volkswagen will add V2H technology to vehicles with its 77kWh battery by the end of 2022 with an over the air update.

For V2H to work, an electric car needs to have bi-directional charging, and you need a smart charger with bi-directional charging as well.

Your electric car sends power to the V2H-enabled smart charger, which then handles the transfer of power to your distribution board and energy storage system. Your smart charger acts as a middleperson to collect energy data.

Vehicle to home benefits

There are two big benefits to V2H:

  • Beat soaring energy prices – charge for free at supermarkets and for very little with an EV tariff, then run your house off that energy.
  • Avoid power cuts – Storm Arwen left 30,000 households without power last year. With V2H, those homes would have been fine.  

V2H vs V2G vs V2L – what’s the difference?

V2H, V2G and V2L are all bi-directional charging features, however, the technologies that enable them are slightly different.

Vehicle to home (V2H) is a bi-directional charging feature that uses your electric car battery to power your home, sending power to your distribution board or an energy storage system like a Tesla Powerwall.

Vehicle to grid (V2G) is a bi-directional charging feature that sends power in your electric car battery to the grid. With a V2G charger, you can sell energy back to the grid, although there isn’t a mechanism in the UK for this yet.

Vehicle to load (V2L) is a bi-directional charging feature that uses your electric car battery to power devices and appliances directly. With an adapter, you can power 3-pin appliances and charge other vehicles at 3-pin speeds or faster.

Will V2H activities degrade battery life?

As EV batteries age and undergo charge cycles they lose charge capacity and power capability. V2H and V2G create additional charge cycles, so logic dictates that V2G activities will degrade battery life.

However, it isn’t so clear cut.

“Analytical results [from the study] show that providing V2G services does not necessarily accelerate the battery degradation; in some cases, it even mitigates the ageing process,” this study concludes. “A case study undertaken shows that, compared to non-V2G scenario (no battery discharging to the grid), battery capacity loss under V2G is reduced by 13.51%.”

So, V2H and V2G activities won’t degrade battery life by any meaningful amount. In fact, predictable activities could extend battery life. However, the study is clear that you need an ‘optimised’ or ‘smart’ V2H/V2G system, i.e. a smart charger.

In the future, we might all power our houses with electric cars, or at least some aspect of them. What a time to be alive.

Alfred Maxwell
Alfred drives a Tesla Model 3 Standard Range Plus but has his eye on a fully-electric pick-up truck. He'd love an electric Ford Ranger, which should be a real thing in a few years!