What is bidirectional charging and how does it work?

Bidirectional charging is the process of using the energy in an electric vehicle's battery to power other sources. In a typical electric vehicle charging event, a connector from a charging station is plugged into an EV to refill its battery. According to Edmunds, most electric cars will primarily use that stored energy for operating and moving, but those equipped with bidirectional chargers can reverse the power flow from the EV battery to camping equipment, power tools, a house and even the electrical grid itself.

How does bidirectional charging work?

Power from the grid is distributed using alternating current (AC) but EVs store energy in the form of direct current (DC). When an electric vehicle is plugged into an outlet, wall charger, or Level 1 or Level 2 charging station, the AC is converted to DC by a relatively small charger on board the vehicle. In contrast, when an EV is plugged into a DC fast-charging station (such as a Tesla Supercharger), AC is converted to DC by a freestanding charging station, allowing electricity to flow into the EV battery at a much higher rate. For the majority of EVs, the flow of power is one-way, but vehicles capable of bidirectional charging can send the flow of electricity outward. The energy is converted back into AC, where it can be sent to a variety of secondary sources.

What are the types of bidirectional charging?

There are a few different types of bidirectional charging, including a few that haven't been implemented on passenger EVs.

• Vehicle to load (V2L): This is the most common type of bidirectional EV charger, and you might even be familiar with it if you're coming from an internal combustion engine car. Simply put, this is the ability to power an external source by using the energy stored in the car. Any vehicle — whether an EV or a traditional gas-engine car — equipped with a 120-volt household-style three-prong outlet can run electrical devices or even small appliances. Some EV owners can also buy adapters that plug right into their car's charge port and have a household-style outlet on one end.
• Vehicle to vehicle (V2V): An EV charging another EV? It's not a pipe dream, but there are limits to the practicality. A charged electric vehicle is a source of power and, in theory, can lend electricity to a fellow traveler who couldn't quite make it to the next station. However, since many current EVs have slower 120-volt outlets, the low electrical output creates a significant charging bottleneck. The receiving EV will only add a couple of miles of range per hour unless the donor vehicle is equipped with high-output outlets. The Ford F-150 Lightning with the Pro Power Onboard package is one such EV. This option equips the Lightning with numerous outlets in the bed, including a faster 240-volt plug capable of offloading 7.2 kW — many times the amount of electricity as other EVs with a 120-volt outlet. For 2024, most versions of the GMC Hummer EV pickup and SUV also come with larger onboard chargers with bidirectional charging, capable of providing 6 kW of energy to other vehicles.
• Vehicle to home (V2H): Power outages at home could become a thing of the past with vehicle-to-home charging. In the event of a power outage, you can use your EV to power your home, provided you have a vehicle and charger with bidirectional capability. There are some other stipulations as well — Ford, for instance, requires that third-party company Sunrun handle the installation of the at-home charger — and you might need to install a secondary unit that switches the house's power draw from the grid to the charging station (and, therefore, the EV). Otherwise, as long as you meet your individual vehicle's requirements, you can essentially use it as a battery to power your home.
• Vehicle to grid (V2G): Unless your charger is hooked up to solar panels, the electrical grid will supply the power to charge your EV. With vehicle-to-grid technology, you can reverse this flow and sell your energy back to the grid. To understand how this is beneficial, you must first understand the ebbs and flows of the grid's power demand. According to the U.S. Energy Information Administration, on-peak hours are generally defined as between 7 a.m. and 11 p.m. on weekdays, with the several hours before and after 5 p.m. being the most stressful on the grid. This is why the price per kilowatt-hour is higher during these times than others. 

With V2G, you can charge your vehicle during off-peak hours when electricity is cheapest and there's little strain on the grid. Then, during peak hours, you can sell your electricity back to the grid, helping increase the grid's power supply. At an individual level, you'll earn money (or a discount on your utility bill) by letting the grid use your car as a battery. As EV owners and operators buy into this system en masse, the combined efforts can help normalize the grid's supply during the day, reducing the risk of brownouts and blackouts.

Combining V2G and V2H is another way to reduce your electricity bill. Instead of selling power back to the grid during peak times, you can charge your car at night with cheap electricity, then tap into the battery to run your house's air conditioning in the hot summer afternoons when power is more expensive. 

Which vehicles offer bidirectional charging?

Bidirectional charging is a relatively new technology, and there aren't many electric vehicles equipped with two-way onboard chargers that enable it. At the time of publication, the following vehicles support bidirectional charging in one or more of the types explained above:

• Ford F-150 Lightning (7.2 kW on one circuit)
• Genesis Electrified G80 (1.9 kW)
• Genesis Electrified GV70 (1.9 kW)
• Genesis GV60
• GMC Hummer EV and Hummer EV SUV (6 kW) (2024 and newer models)
• Hyundai Ioniq 5
• Hyundai Ioniq 6
• Hyundai Kona Electric
• Kia EV6
• Kia EV9
• Kia Niro EV
• Lucid Air
• Mitsubishi Outlander PHEV (Plug-In Hybrid) (1.5 kW)
• Nissan Leaf (business fleets only)
• Rivian R1T
• Rivian R1S
• Tesla Cybertruck (11.5 kW)

How much do bidirectional chargers cost? 

The cost of bidirectional chargers and their installation varies. Ford is one of the few EV manufacturers to sell a first-party-branded solution. Its Charge Station Pro (codeveloped with Siemens) is included in the MSRP of an F-150 Lightning with the extended-range battery but not the standard-range battery. At the time of publication, the cost for this station if you opt for a standard-range pack is $1,310. Soon, General Motors will launch kits through its Ultium Home brand to support V2H charging for GM EVs powered by Ultium batteries. In most cases, you'll find bidirectional chargers produced and sold by third-party companies. These chargers include the Wallbox Quasar 2 and dcbel r16, with the latter offering an interesting dual charge cord configuration for households with two EVs.

The Enphase IQ EV charger is another intriguing choice; a single app connects the Enphase bidirectional charging unit, Enphase's wall battery packs and Enphase-enhanced solar panels, giving users an immediate view of how the power is flowing in their house. At the time of publication, pricing for the Quasar 2 was not available, and the dcbel r16 starts at $4,999 (this price climbs as you specify connectors). IQ units cost between $732 and $1,176, depending on amperage. Installation costs are harder to predict, as they will vary by the complexity of the installation and the specifics of your electrical panel.

This story was produced by Edmunds and reviewed and distributed by Stacker Media.