Renault Group
Electric mobility | 01 April 2021

Advantages and installation: all you need to know about the Wallbox

5 min
At home or at the office, a Wallbox is often the most popular solution among electric vehicle drivers. This device has many advantages, being a more reliable and faster way to charge than through a power outlet.
by Renault Group

One of the many advantages of having an electric car is being able to charge it at home — no need to stop off at the service station! You just need to figure out how to go about it, both quickly and safely. Your potential solution is: a Wallbox.

What is a Wallbox?

Wallbox is an electric car charging point which takes the form of a wall-mounted box. It can be installed in a private garage or an apartment block or company parking lot. Several electric vehicle manufacturers, including Renault, recommend opting for this solution.

How does a Wallbox work?

The wall-mounted box is connected to the electrical grid by a dedicated circuit that can take a greater load that a regular domestic circuit. The Wallbox works by receiving electricity from the grid and converting it into the type of current your car’s battery can store. When charging through a domestic plug socket, the electricity has to go via the car’s inbuilt converter, aka onboard charger, but this is no longer necessary with a Wallbox.

What are the advantages of a Wallbox?

Electric vehicle drivers who have opted for a Wallbox at home enjoy its many advantages.

Wallbox at home: practicality

Arguably the greatest advantage of the Wallbox charger is its practicality. You park your car after work, hook it up to the Wallbox overnight, and it is ready to go for the next morning. Plus, with Renault ZOE, you can multi-task anywhere you charge by programming interior heating or cooling for when you get into the vehicle. Not only does this mean a comfortable interior from the moment you sit down, but you also don’t have to use up battery energy to regulate the temperature when driving. Ideal for the morning commute!

Eco-friendly economy

The Wallbox is where saving money meets environmentally friendly behavior. When charging from home on a Wallbox, drivers can make the most of lower overnight electricity rates and put less of a strain on the grid. To take smart charging a step further, the Renault Z.E. Smart Charge app allows users to recharge at the most opportune moments, for example when electricity supple outweighs demand.

Optimal safety

The Wallbox is also equipped with electronic features that safeguard against the risk of overheating, electric shock and voltage peaks which can not only disrupt efficient battery charging, but also be a safety hazard. Equipped with its own self-diagnostic system, the Wallbox can deliver a high-wattage power supply for several hours without posing any risk to the electric system, keeping the home and its occupants safe. Its components are designed to prevent any power surges. The same can’t necessarily be said of regular power outlets, which are not recommended for charging over a long period (except for the Renault Twizy).

A shorter charging time

Another advantage of the Wallbox charger is its rapidity. Whether 3.7 kW, 7.4 kW or 22 kW, the wattage of a Wallbox will be much higher than that of a regular domestic power outlet (2.3 kW). Consequently, the charging time is significantly lower. For example, a ZOE will reach full charge, i.e. a range of 395 kilometers WLTP*, in under 10 hours minutes on a 7.4 kW Wallbox, compared to well over 25 hours from a domestic socket! For Twingo Electric it takes 4 hours on a 7.4 kW Wallbox, or 15 hours from a domestic socket.

A Wallbox: easy to use

To start charging, all you have to do to is hook the electrical Wallbox charger cable up to the car. This way there’s no need to unravel the charging cable and put it all away again afterwards, like you have to with a regular domestic power outlet.

Which kind of Wallbox should I choose for my Renault ZOE?

Several electrical Wallbox charger models are available on the market, offering solutions to suit the electric systems of homes and businesses. It all depends on the meter wattage and the way the electricity is carried (single phase or triple phase, with most private individuals using single-phase meters). Single-phase domestic electric systems are enough to charge a ZOE with a 7 kW Wallbox. If your electric system has a triple-phase supply, you can even opt for a 22 kW Wallbox.

With this information to hand, the electric vehicle manufacturer will guide their customer to a contractor who can offer the most suitable solution to the future buyer.

How do you install a Wallbox?

Concerned about installing a Wallbox yourself? No need. The contractor will show you the best location for the Wallbox and take care of installation, including a diagnostic test of the domestic electric system, notably measuring the resistance of the grounded socket. Once the power supply is shut off, the Wallbox is hooked up to the electric panel. This generally takes from one to five hours.

Did you know? In an increasing number of countries, such as France, Spain, Japan and India, any electric vehicle driver living in a shared apartment block has the right to the installation of a charging outlet on their parking space.

Can I use my home charging unit on another electric car?

One Wallbox serves one electric vehicle at a time. For homes and businesses with more than one electric vehicle to charge at the same time, separate Wallboxes will be needed. However, if your concern is about two different brands of electric car alternating use of the Wallbox charger, then it depends on the cable type. With a type 2 cable (now the European standard), any number of electric vehicles (regardless of their brand) can use the same Wallbox charger.

What’s the price of a Wallbox?

Wallbox prices vary between manufacturers, but generally lie somewhere between 500 and 1,000 euros. On top of this, the installation cost is 300 to 600 euros. But there’s good news: to bring the costs down, in many cases you can qualify for government aid.

Government grants to help the process

In the UK, for example, electric vehicle drivers can benefit from the OLEV (Office for Low Emission Vehicles) EVHS (Electric Vehicle Homecharge Scheme) grant, which offers up to £350 off the cost of purchasing and installing a home charging point from April 1, 2020. If you qualify for the grant, a Wallbox installation partner will take care of the claim on your behalf and take the allocated amount off your eventual invoice. Businesses in the UK can also take advantage of government incentives. You can claim up to £10,000 for 40 chargers as part of the WCS (Workplace Charging Scheme), a voucher-based scheme designed to help the upfront costs of purchasing and installing Wallbox chargers.

In France, this aid takes the form of tax credits: private individuals can deduct 30% of the installation cost of a Wallbox from their tax bill. When it comes to businesses, subsidies of up to 40% off the purchase and installation of Wallbox chargers are provided as part of the ADVENIR program dedicated to rolling out EV charging infrastructure across France.

Other countries also offer grants and tax benefits towards the purchase and installation of charging units like the Wallbox. To see what subsidies or other financial incentives your government provides, visit the Wallbox website.

The future of the electrical Wallbox: bidirectional charging

What if you could charge your electric vehicle and also give back to the grid, aka Vehicle-to-Grid (V2G), or the home, aka Vehicle-to-Home (V2H)? This is the principle behind bidirectional (or “two-way”) charging. The idea is that your electric vehicle often sits attached to a charger despite being fully charged — overnight, for example. Bidirectional EV chargers are used to supply electricity back to the grid or the home.

This emerging technology means, for example, that you could charge your electric car at night, when there is less demand for electricity, and then use that electricity to power your home during the day (V2H) or help balance energy supply and demand on a local, even national, scale (V2G). A more balanced power supply means lower costs and more reliable electricity for everyone. Plus, balancing energy demand in real-time results in more electricity sourced from renewable energies such as solar, wind power, by their nature intermittent. Not to mention the potential of selling excess energy back to the grid!

The multiplication of electric vehicles combined with their unidirectional and (in particular) bidirectional smart charging capacities, facilitates the use of intermittent green energy sources. This then encourages the introduction of more such sources, which in turn leads to a grid supplied with a higher percentage of green energy. Bidirectional charging systems therefore offer a form of energy supply that is beneficial, not only for vehicles, but for the planet.


*WLTP: Worldwide Harmonised Light Vehicle Test Procedure. The standard WLTP cycle corresponds to 57% of city journeys, 25% of suburban journeys and 18% of motorway journeys.

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