ISO 15118: The Standard You Can’t Afford to Ignore Any Longer

You’ve seen it… over, and over, and over again, whenever you read about bidirectional charging or Plug & Charge. “ISO 15118 is the key.” This standard appears more and more often when it comes to discussing innovative EV charging. 

But what role does it play exactly? And what do you need to know about it, so you don’t feel lost in the next conversation about e-mobility? Find out here.

• ISO 15118 enables Plug & Charge and V2G bidirectional charging.

• At the moment, not all electric vehicles and chargers support ISO 15118.

• Smart wallboxes can serve as a practical alternative, offering many intelligent features while ISO 15118 adoption continues to grow.

ISO 15118 is a standard that defines how electric vehicles and charging stations, both AC and DC, communicate. It’s their common language that outlines how messages are structured and exchanged, and enables, among other things, bidirectional charging and Plug&Charge. 

Without ISO 15118, the parties involved would send data in different formats following different rules. Obviously, they wouldn’t be able to understand each other. 

Most industry players agree that standards like this one are essential for the broad acceptance of e-mobility. They help different providers to become part of a unified system and create the foundation for scalable, future-proof charging infrastructures.

• Plug & Charge makes charging easier

• Uses encryption and digital certificates for safety

• Bidirectional charging could support grid stability

• Built to handle the upcoming wireless charging

• Many EVs don’t support the standard yet

• A lot of chargers don’t support the standard yet

• Authentication can delay charging by several seconds

• Feeding power back to the grid isn’t widely used yet

ISO 15118 consists of many complementary sections that work together, and ISO 15118-20 is one of them. This specific update adds wireless charging, bidirectional charging, and ACD charging* to the list of possibilities. The other ones, like ISO 15118-8, are just improvements to the basic standard. 

* Wired, automated connection that requires no manual plugging

ISO 15118 enables Plug & Charge and bidirectional charging. The first one means that your car can be recognised automatically by the station for charging to begin. The second indicates that the system allows you to send energy stored in your car battery to the grid or a building.

To give you a better image, here’s the standard performing Plug & Charge. 

1. You arrive at the charging point. 

2. Physical connection is made (via a cable or wireless pad).

3. The EV and charger exchange messages using ISO 15118 rules.

4. The charging station or backend system identifies the car.

5. If you’re at a public charging station, the charger checks with a backend system (e.g., your charging provider) to confirm billing.

6. Charging starts automatically.

7. Optionally, the car and charger can negotiate when and how fast to charge (based on the user settings, grid demand, etc.)

Your electric car supports ISO 15118? Awesome! This means you can enable Plug & Charge and enjoy charging with your favourite providers without having to use an RFID card or app every time. The prerequisite is, of course, that the charging providers support ISO 15118 as well. 

Some charging networks, like IONITY, already support Plug and Charge. Starting October 14, 2024, all public AC and DC chargers in Germany must be digitally connected. They must be able to communicate bidirectionally with the power grid and the electric vehicle. While ISO 15118 isn’t required by name, its features match the new rules, so more networks will likely support it.

The whole concept of Plug & Charge is that identification and billing happen automatically without you having to do anything. When payment is involved, you might naturally have concerns about the safety of your digital wallet. But you don’t need to worry, as it’s been thought through. Unlike Autocharge, which uses a car’s MAC address and doesn’t offer full data protection, ISO 15118 uses cryptographic layers and encryption techniques to ensure that all communication is secure and confidential.

• No need to authenticate with an app, card, or QR code

• All the data is well protected 

• It’s not widespread 

• Some older electric cars can’t use PnC

ISO 15118-20 enables electric vehicles to not only draw power from the grid but also send it back when needed. This opens the door to smarter energy management, improved grid stability, and more efficient use of renewable energy.

ISO 15118 helps connect electric vehicles to the smart grid. We are talking about the grid that uses digital communication to connect energy producers, users, and components like transformers. Once you allow V2G charging, the system considers grid data, the current battery level of the car, and your desired state of charge by a specific time to create a personalised charging plan. This helps match energy supply and demand.

• Reduces strain on the power grid

• Supports renewable energy integration

• You can earn money by selling energy

• Might increase battery wear over time

• Not yet widely supported by utilities

• Complex regulation and billing models

V2H takes the same concept as V2G but brings it into your house. The idea is simple: your electric car can act as a backup power source. It can supply electricity to the building during peak hours or outages. ISO 15118-20 makes this possible by enabling communication between your car and home energy system. V2H can even bring you financial benefits if you’re using solar panels and/or flexible energy tariffs.

• Powers your home during outages

• Lowers electricity bills using stored EV energy

• Boosts self-sufficiency with solar integration

• Needs home energy system compatibility

• Limited by EV battery size and charge level

• Still emerging in many markets

ISO 15118 allows the EV and charger to exchange dynamic load information. OCPP 2.0.1 (the version required for successful ISO 15118 operation) enables communication between the charger and the backend system. Together, they enable a smart charging schedule that can be (re‑)negotiated in a grid‑friendly way.

This helps to:

• Optimise charging times and rates

• Avoid grid overload (peak shaving)

• Make better use of renewable energy

Be honest, you’d love it if charging your car was as easy as plugging in your phone, no matter where you do it. ISO 15118 can make that happen. Plus, it opens the door for you to earn money by feeding power back into the grid. And it’s not just EV drivers who benefit.
Here are other parties interested in ISO 15118:

• Fleet managers

Imagine managing 50 or even 100 electric delivery vans. Normally, that means

a) you need to teach drivers how to use a charging card or an app

b) sometimes you have to deal with various technical issues that may arise from that

With ISO 15118, all that headache is gone. Well, at least in theory. The system recognises the vehicle and handles charging and billing automatically. So the only thing drivers will need to do is plug in the vehicle. As before, they will have the option to download an app to track the charging if they want to leave the van and go on a long lunch break.

• Homeowners with solar panels 

If you have solar panels and an EV that supports V2G, you can use this combo to earn a pretty penny. On sunny days, your car can store the excess power in your car battery, and in the evening, when the energy demand is high, you use that energy at home or sell it back to the grid. While the system is not widespread yet, it holds very promising potential for the future. 

• Charging point operators 

ISO 15118 can make charging easier for EV owners using public charging points. Instead of dealing with RFID cards, apps, or payment errors, drivers can simply plug in and walk away. The vehicle and charger communicate automatically to start and manage the session. This means 

• fewer failed charging attempts

• less confusion

• fewer support calls

For operators, that translates into better customer satisfaction.

• Smart grid operators

Smart grids are becoming increasingly popular. ISO 15118 is one of the ways to use their intelligence to avoid overloads. There are plenty of situations when that risk is especially high. Think of a hot summer day in the city, with AC systems on and electric cars charging in every third household. That puts serious pressure on the grid. Bidirectional charging made possible by ISO 15118 can help ease that load. Less pressure = less risk of a power outage.

The main challenges for ISO 15118 adoption are limited compatible chargers, complex certificate management, firmware mismatches causing failed connections, and authentication delays ruining the supposed-to-be-enjoyable Plug & Charge experience. V2G support exists but is hindered by regulatory barriers.

A growing number of EVs, like the 2021 Porsche Taycan, Mercedes-Benz EQS, Lucid Air, Ford Mustang Mach‑E, and newer BMW models, support Plug & Charge. But that’s still not enough.

As for the charging stations, many AC chargers are now being built with the necessary hardware for Plug & Charge. However, the standard for AC implementation has not yet been finalised, which is why software support is still missing. On the DC fast charging side, even when Plug & Charge is supported, outdated firmware can cause connection issues and frustrating failed sessions.

Implementing Plug & Charge requires a robust public key infrastructure (certificate issuance, revocation, storage). ISO 15118-20 further demands larger certificates (up to 1600 bytes) and TLS 1.3, which can strain EV/charger hardware. 

The certificate handshake and TLS session setup can take several seconds or more, especially on congested networks. Such delays undermine the intended “Plug & Walk away” simplicity.

ISO 15118‑20 includes V2G support. However, the market adoption is limited due to regulatory hurdles, lack of incentives, and few bidirectional-capable chargers. Right now, V2G is mostly experimental. 

For example, the project “Utrecht Energized” is Europe’s first working V2G car-sharing network. It started with 50 Renault 5 E-Tech electric cars and special chargers from We Drive Solar, managed by MyWheels. The goal is to grow to 500 cars using Mobilize’s V2G system, which could provide about 10% of the local grid’s flexibility and help balance energy from solar and wind. But for now, it’s still a pilot project.

ISO 15118 enables features that can contribute to grid load balancing and make charging really easy. But while the standard is not too widespread yet, you can benefit from similar possibilities without it. For instance, with the smart functionality of our go-e Charger, you can optimise your EV charging in several other ways. 

Among many other features, the wallbox offers: 

• Load shifting 

Our go-e Charger and go-e Controller don't require V2G communication and can still allow you to shift the load in an equally efficient way. Schedule energy usage for off-peak hours, and charge your electric vehicle at home when electricity demand is low. It can have a positive impact on both the environment and your energy bill.

• PV surplus charging 

Though being able to sell electricity you received earlier from the grid or your solar panels may seem like a perk, V2G communication is not a necessary feature when buying a wallbox. The selling energy price is usually very low compared to the buying price. You can profit much more by using surplus energy to charge your electric vehicle. The go-e Charger combined with the go-e Controller or any other EMS will handle this for you.

• Plug & Play as an alternative to Plug & Charge

Plug in the go-e Charger, connect it to the vehicle, and the charging process will start automatically. You can change these settings so that you need to initiate charging with an app or RFID card, but for protected areas, Plug & Play can be extremely practical. 

As of June 2025, many DC chargers support ISO 15118 and are already in use for Plug & Charge. In contrast, AC chargers supporting the standard are only ready on the hardware side. The software solution for AC Plug & Charge is still to be finalised. Anyway, let’s have a look at what’s already available. 

DC charging networks offering Plug & Charge according to ISO 15118: 

• IONITY

• Aral Pulse

AC charging stations supporting ISO 15118:

• go-e Charger PRO

• ABL eM4

• innogy eBox Professional Wallbox

• Home Charger Touch

• Amperfied Heidelberg Connect Business

• Elli Charger PRO

• Menneke's AMTRON® Professional

• Webasto Live

• Webasto Next LU

• Walther Werke smartEVO 11

• TechniColt 1100 Smart

• Juice Charger me

• Keba x-series

Electric vehicles from leading manufacturers like BMW, Audi, Hyundai, and others already support ISO 15118. The number of compliant models continues to grow. It's highly likely that all new models from brands that have already adopted the standard will support it as well.

Check out the list of ISO 15118-compliant electric cars:

• Audi: e-tron, e-tron Sportback, e-tron GT, Q4 e-tron, Q4 e-tron Sportback, Q6 e-tron, Q8 e-tron, Q8 e-tron Sportback

• BMW: iX1, iX2, i5, i5 Touring, iX, i7 

• Cupra: Born

• Ford: Mustang Mach-E

• Genesis: GV60, Electrified GV70, Electrified G80

• Hyundai: IONIQ 5, IONIQ 6

• Kia: EV9, EV6

• Lucid: Air

• Mercedes: CLA with EQ tech, EQA, EQB, EQE, EQE SUV, EQS, EQS SUV

• Porsche: Taycan, Taycan Cross Turismo, Taycan Sport Turismo, Macan

• Renault: Megane E-Tech Electric, 5

• Škoda: Enyaq iV, Enyaq Coupé iV

• Smart: EQ ForTwo

• Volvo: EX30, EC40, EX40, EX90

• VW: ID.3, ID.4, ID.5, ID.7, ID.7 Tourer, ID.Buzz

You need to know that ISO 15118 is not a capability that can be added via software if the vehicle hasn’t been prepared for it on the hardware side. This means that the chargers and electric cars that do not support the standard will not be able to get updated. You can only hope that newer models from the manufacturer of your choice will be compatible with it. 

Yes, ISO 15118 is the future of EV charging. The proof of this is the already great number of vehicles and charging stations supporting the standard growing constantly.  

We’ve been toying with the idea of writing about ISO 15118 for over a year. And when we recently looked back at some early drafts from late 2023, our reaction was: “Wow!” The number of compatible vehicles and chargers has skyrocketed since then.

But when you think about it, this trend was only a matter of time, given how ISO 15118 improves the charging experience.

The standard boosts convenience with Plug & Charge (who can say no to an easier life, right?) and makes the whole process more sustainable thanks to the V2G capabilities. The protocol unites electric vehicles and charging stations into one system. This way, it provides richer information exchange, such as vehicle status and charging session details, improving transparency and user control. All in all, the future of ISO 15118 looks very bright, and we’re excited to see where it goes next.