It is very possible that these days you have read that BMW is using electric car batteries as a power source for ColdPlay concerts. This way of giving batteries a second useful life is just one of the many possibilities they offer beyond their conventional use; another not so well known is what is known as bidirectional charging.

Bi-directional charging turns electric vehicles into energy stores. This technology offers many benefits, including saving money with each charge. We see it in detail…

What is bidirectional charging

As its name suggests, bidirectional charging is the one that is carried out in two directions. On the one hand, the electric car takes the amount of energy that it can store in its battery from a power outlet (the time it takes to recharge will depend, among other factors, on the type of connector used). That electricity can then be used to power the vehicle’s engine or as a power generator to charge other devices.

This technology is based on a very simple idea: in the same way (or almost) that energy enters the battery, it can leave and thus serve to power any other electrical device. This video explains it in detail:

It must be clarified that the process by which energy enters the battery is not the same as the one necessary for it to leave. When an electric vehicle is charged, alternating current (AC) from the grid is converted to direct current (DC) through the charger. But for that same electricity stored in the battery to be returned to the home or to the grid, it must be converted back into DC, hence the need for a bidirectional charger.

Bidirectional charging is especially useful in combination with a solar self-consumption installation. The energy captured by the solar panels is stored in the car at zero cost and is then used either to run the vehicle’s engine or to power other devices.

Bidirectional charging types

Although the operation is the same in all of them, there are several two-way charging types depending on the use to which the energy is allocated:

  • Vehicle to Grid (V2G): the energy stored in the battery of the electric car is returned to the electrical network
  • Vehicle To Home (V2H). In this case, the electricity from the battery is used to supply light to a home. With a single battery it will not be enough to supply all the needs of the house but it is a very practical solution at specific moments, for example, in the event of a power outage
  • Vehicle To Load (V2L). V2L capable cars feature a DC to AC inverter; This technology allows you to connect other loads to the outlet and use battery power
  • Vehicle To Vehicle (V2V). Bidirectional V2V charging allows one electric car to serve as a power source for another. This technology is very practical, for example, to recharge the batteries of a scooter or an electric bike

Electric cars with two-way charging

Not all electric vehicles can serve as a power source for electrical devices, only those that are equipped with a two-way charger.

Nissan has always been a pioneer brand when it comes to electric mobility. In their rows militates one of the first electric for sale in our country, the nissan leaf. With this car he did the first two-way load tests more than three years ago. The scenario for the demonstration that the charging system for external devices with electric car batteries worked was the installation of 15 bidirectional charging points in the Johan Cruyff Arena in Amsterdam.

test ioniq 5

Hyundai is another of the manufacturers with a firm commitment to the two-way recharge. The Korean brand has two models with two-way charging for sale: the Ioniq 5 and the Ioniq 6.

He Ioniq 5 is equipped with V2L technology. The driver can plug in any device or charge electrical equipment up to 3.6 kW with the on-board 230 V socket. You can also use an converter that connects to the external charging port and power devices up to 3.6 kW when the car is not running.

Only a few weeks ago the brand inaugurated the Hyundai Hotel, the first hotel establishment without connection to the electricity grid. Located in Sessex, one from central London. The hotel has a suite room of guests, a bar, a restaurant and a cinema and it is all powered by various Ioniq 5s parked around the hotel.

Hyundai hotel two-way charging

Another model with bidirectional charging is the Kia EV6. Like the Ioniq 5 it has 3.6 kW V2L charging.

Save with bi-directional charging

There are studies that affirm that the use of bidirectional charging allows you to save up to 400 euros a yearalthough the amount will depend on the amount of energy used and the number of times this system is used.

Bidirectional charging saves money because it allows you to choose the energy source based on tariffs. For example, if you need to increase the consumption of your home at times when your rate is more expensive, you can choose to have the vehicle battery provide that extra electricity (the car will have been charged at a cheaper time, hence the savings).

There are also drawbacks. There are experts who affirm that, just as happens if ultra-fast charges are abused, bi-directional charging speeds up battery degradation thereby reducing its useful life.