May 2023
|Last updated:
January 2025

Bi-directional charging

Bidirectional charging header (V2H)

Bi-directional charging is just one of the many new technological developments in the EV world that will encourage a sustainable lifestyle. EVs and their batteries are beginning to offer more than zero-emission travel; creating new ways to utilise renewable energy more efficiently whilst enabling EV owners' independence and flexibility when it comes to their energy supply!

In this blog, we delve into bi-directional charging, some of the benefits it can provide, and whether it’s worth investing in as an individual or a business owner.

Let’s get plugged in…

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What is bi-directional charging, and how does it work?

Bi-directional charging does what it says on the tin - instead of energy only going one way as it would in a regular charge (e.g. from the charger to the EV battery), it also gets discharged back again (to another energy-fuelled recipient). So, how does this work?

To use bi-directional charging, your EV’s onboard system and your EV charger have to be compatible; this means that both of these need to have a bi-directional converter.

The converter transforms the EV’s energy from DC to AC - this means it’s possible to safely transfer the energy to the onwards recipient.

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To learn more about AC/DC chargers, check out our blog: EV Connectors and Speeds

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Where does the energy go?

There are four key types of bi-directional charging which you can invest in as an EV owner, each involving different recipients:

1. Vehicle-to-grid (V2G) technology is the most common form of bi-directional charging. EV owners can capitalise on this by sending energy back to the grid and earning money by doing so. 

This technology also helps with something called grid balancing, ensuring that supply and demand are equal at all times! 

During low-demand periods, the EV can charge from the grid, storing the energy to be used in a high-demand period when fossil fuels and the grid are being used most.

A bidirectional charger and a compatible EV is required for this type of bi-directional charging.

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If you’d like to learn more about V2G technology and EV tariffs that are utilising this technology, visit the Octopus Electric Vehicles website and check out some FAQs!

2. Vehicle-to-load (V2L) technology is all about using your EV’s battery to power/charge external devices. It’s becoming one of the more commonly used forms of bi-directional charging due to its convenience and availability!

Lorry drivers often utilise this technology to charge their appliances and tools on their way, as stopping to charge up would add additional time to their journey. It’s also a great convenience for anyone camping in remote areas or for construction workers needing to charge their tools.

A bidirectional charger is not required for this type of bidirectional charging but a compatible EV is still essential.

camping zapman charging his appliances with his EV
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The MG ZS is one EV model that features V2L bidirectional charging. Once the V2L adapted lead is connected the EV is essentially turned into a portable battery!

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3. Vehicle-to-home (V2H) technology. This type of charging requires a suitable connector, enabling the power to be fed in. One way to utilise the EV whilst it’s stationary is by storing solar energy generated during the day - this renewable energy can then be used to save homeowners money on grid electricity and can work as a backup power source for the home, providing energy independence for those who make use of this technology efficiently.

For this technology to work, you'll need a compatible bidirectional charger and additional equipment, such as a CT meter (Current Transformer) which must be installed at the main grid connection point. This is necessary to support any connection carrying a load greater than 100 Amps. Your EV must also be compatible.

EV charging home with zapman
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4. Vehicle-to-vehicle (V2V) technology. In the (unlikely) situation that you’ve run out of charge in the middle of nowhere, V2V tech could be your saving grace. Simply hook up to another EV and charge off its battery. Although this is the least discussed of all the forms, it could be a lifesaver in sticky situations.

A bidirectional charger and two compatible EVs are required for this type of bi-directional charging.

An EV charging another EV
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What are the main advantages of bi-directional charging?

Saving/earning money (V2H, V2G)

Utilising your EV to power your home (V2H) can result in significant savings on your energy bills! Charging your car at night when energy is considerably cheaper and using that energy to run your home during the day would help reduce your monthly statement.

V2G charging can make you money! With this form of bi-directional charging, you can sell energy back to the utility company for redistribution, capitalising on your EV’s energy supply.

Portable charger (V2L)

As previously mentioned, EV batteries can be used to charge appliances and can therefore be used on long journeys to avoid unnecessary stoppages.

Back-up power (V2H)

Storing backup power for the home not only saves you money but also offers reassurance. For example, in the instance of a power outage, the homeowner would have another source of energy, avoiding reliance on the grid!

It also provides more self-sufficiency, combining grid-generated energy and EV power to save the homeowner money.

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Intelligent Octopus Go is a smart tariff that uses its knowledge of the variation in energy pricing to reduce Octopus Energy customers’ bills - find out how on their website!

Intelligent Octopus Go customers also get 8% off charging with Electroverse.

Main disadvantages of bi-directional charging?

Availability

Only a few companies are putting time and money into bi-directional charging, so availability needs to be higher. Wallbox is one of a small handful of companies that have manufactured bi-directional home chargers to charge your EV, power your home or send the energy back to the grid. Check out their Quasar charger to see what they have to offer!

Capability

Bi-directional chargers can only work with vehicles that are compatible with two-way DC charging. Bi-directional charging capability needs to be built within the electric vehicle, and therefore, only a minimal amount of EVs are currently compatible with bi-directional charging.

The Nissan Leaf, the Ford F-150 Lightning and the Mitsubishi Outlander PHEV are presently the only three brands that offer V2G and V2H.

V2L is available in the Hyundai Ioniq 5, the Kia EV6, the Genesis GV60, the BYD Atto 3, the BYD Han EV, the Ford F-150 Lightning and the MG ZS EV (2022).

Cost

Bi-directional charging requires the adaptation of chargers and vehicles and can therefore involve spending money before you begin to save it. In the case of V2G and V2H, the EV still requires expensive extra technology. Home chargers must be updated before they’re ready to redirect any energy generated. For example, special charging leads and accessories are necessary for the energy transaction - creating additional costs.

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When can we expect bi-directional charging to become more accessible?

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OEV (Octopus Electric Vehicles) have been working on a V2G project, aiming to boost renewable energy on the grid, called Powerloop. Find out more here!

Whilst this technology is heading in the right direction, all the variables and vehicle alterations that come with it mean that bi-directional charging has some way to go before it's universally affordable and accessible. However, if the rapid growth and improvement of EV technology is anything to go by, then it’s worth keeping your eyes peeled for the commercialisation of bi-directional charging!

What is bi-directional charging for EVs?

Bi-directional charging allows energy to flow both into and out of an electric vehicle's (EV) battery. This means the EV can not only charge from the grid but also supply power back to the grid, home, or other devices.

How does Vehicle-to-Home (V2H) technology work?

V2H enables an EV to supply power to a home. By using a bi-directional charger, the energy stored in the EV's battery can be used to power household appliances, providing backup power during outages or reducing electricity costs during peak demand times.

What are the benefits of Vehicle-to-Home (V2H) technology?

V2H offers several advantages, including:

  • Serving as a backup power source during outages.

  • Reducing electricity bills by using stored energy during peak pricing periods.

  • Enhancing energy independence and sustainability.

Which electric vehicles support bi-directional charging?

Not all EVs currently support bi-directional charging. Models like the Nissan Leaf and certain Hyundai and Kia vehicles offer this capability. It's essential to check with manufacturers for the latest information on compatible models.

What equipment is needed for bi-directional charging?

To utilise bi-directional charging, you'll need:

  • A compatible EV with bi-directional charging capability.

  • A bi-directional charger installed at your home or facility.

  • Additional equipment like a Current Transformer (CT) meter may be required for certain setups.

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