Wallbox – Electric car chargers

With a wallbox you can charge your electric vehicle (EV) from the comfort of your home. Keep reading to know how the wallboxes work and what are their benefits.

Wallbox chargers  -

Note: we often hear people refer to wall chargers as “wallbox chargers”, but that is a redundancy since the term wallbox in itself means a charger that’s installed in a wall. That said, we will be referring to these chargers either as wallbox, EV charger or electric car charger.

Wallboxes are the ideal EV chargers for charging your vehicle at home. When charging your electric vehicle at home, you’re taking advantage of slow charging – that better preserve the useful battery-life of your car – and economic charging – using the most favorable period on your energy plan, if you have opted for a bi-hourly plan).

That being said, the process of charging your electric vehicle at home with a wallbox can take quite some time if you’re using a common power socket. In fact, if we’re talking about electric vehicles with a more powerful battery, the total charge can take up to 2 entire days.

Schuko power socket. This is an upgrade of the common power socket (Juice Celsius model), equiped with an integrated temperature sensor that helps to avoid installation overheating when the car is charging.

If we use alternating current (AC), the one that normally exists in our homes, in a common power socket (Schuko – with two round pins), we’ll verify a low charging speed (about 2,3 kW).

This solution does not require any installation. After all, we all have electric power sockets at home! However, and to give you a real example, to charge a Renault Zoe Z.E. 50 with a capacity of 52 kWh, in a common power socket, it would take 29h and 34min only to reach 80% of the total charge. To reach a full charge this car would have to be plugged to the power supply for 37h and 13min.

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This means, car models with a battery of 62 kWh (ex: Nissan Leaf), 64 kWh (ex: Kia e-Niro or Hyundai Kauai Electric), of 75 kWh (ex: Tesla Model 3 Long Range), 80 kWh (ex: Mercedes-Benz EQC 400 4Matic) or 95 kWh (ex: Audi e-tron 55 quattro) turn the total charging time impossible to bear if you’re using a common power socket.

On the other hand, even if you have contracted 4.6 kVA, or above, from your electricity supplier, when you plug the electric car to a common power socket (with 2,3 kW), you won’t be able to extract more than those 2,3 kW out of each power socket.
The fast EV chargers using direct current (DC), should only be used while travelling and the charge of the electric cars should be mainly slow to ensure a longer battery life.

If the power supplied by the common power socket is too low and the charging time too high, the amount of time (accumulated throughout the years) the car remains plugged to the electric supply will cause damage to the battery of your car. This means that, when it comes to electric car battery durability, it is equally damaging to undertake consecutive fast charging sessions, than extremely slow charging sessions.

That’s how wallboxes came to exist. They are a fast and effective solution to ensure more satisfatory charging sessions for electric vehicles’ users from the comfort of their homes.

Wallboxes are charging units powered by alternating current, in single or three phase, that increase the speed in which power is supplied to the vehicle. These devices are normally installed on a house wall (indoors or outdoors).

They range between 2.4 kW and 22 kW

The capacity of a wallbox ranges between 2.4 kW and 22 kW. There are two types of wallbox available in the market:

  • Single phase wallbox between 2.4 kW and 7.4 kW;
  • Three phase wallbox between 11 kW and 22 kW.

AAlternatively, there are other EV chargers in the same range, such as Green-up from Legrand. They charge your electric vehicle at a speed of 3.7 kW (16 A), a bit faster than what the common power socket you have at home allows you to.

This type of socket automatically detects the connection to an electric vehicle and determines the optimum power to supply to its charging session. In 6h your electric vehicle will obtain an autonomy of 100km.

However, the most commercialized wallbox models have a capacity of 7.2 kW or 7.4 kW AC (32A) and their current can be configured from 6A to 32A.
Note: this means that, on average, to reach an autonomy of 100 km you’ll need 4 to 5 hours of charge with a 3.7 kW wallbox; and only 2 to 3 hours if you choose a 7.4 kW wallbox.

That said, it’s clear to who owns an electric vehicle, or a hybrid plug-in, that it is worth considering the investment on a wallbox.

Remember: the larger the battery capacity of your vehicle (and there’s an increasing number of vehicles with an autonomy of over 400 km), the bigger should be the “breath” of the wallbox.

Differences in charging times

So that we can better understand the benefits of having a wallbox, let’s look at the specific case of a 40 kWh Nissan Leaf. If we use a 230V cable plugged to a common power socket, the electric vehicle will charge fully in 21 hours.

If we use a 3,7 kW AC (16 A) wallbox instead, that same car will need only 15 horas to charge its battery at 100%. Using a 7,4 kW AC (32 A) wallbox, will reduce our charging time to 7 horas. That means, less than 2/3 of the time it takes to charge in a common power socket.

With a 7,2 kW wallbox, considering the 62 kWh (Leaf E+), we will need 11 hours and 30 minutes to fully charge our vehicle, as opposed to 32 hours, if we use a common power socket.

Another example: if we connect a Zoe ZE 50 to a 7,4 kW AC (32A) wallbox, it would need 8 hours and 33 minutes to charge at 100% – a very different type of performance from the 37 hours and 13 minutes necessary if we used a connection of 2,3 kW AC (10A).

The most powerful wallboxes, of 22 kW (three phase installation), allow for a faster charging session. However, to charge at 22 kW it is necessary to increase the power to 20,7 kVA and have a three phase electricity meter.

When it comes to choosing your wallbox, you should also aknowledge that the charging time varies according to the size of the battery and according to the vehicle’s internal charger speed.

To calculate the total charging time of an electric vehicle, you should consider the following variables: the power available through the socket or charger; the vehicle’s internal charger; and the size of the battery you want to charge.

EVs’ internal charger

It is good to know that most EVs are limited to 7.4 kW, so, if you have one of these models it doesn’t make sense to invest in a 22 kW charger.
The EV’s internal charger transforms the received electricity, from AC to DC – that’s the deciding factor.

To have an idea of the maximum charging capacity of EV’s internal chargers, we can divide them into 3 categories

The slowest: among these, we have vehicles such as the Peugeot iOn and Citroën C-Zero that can get a maximum charge of 3,7 kW.

The semi-fast: here we have models such as Nissan Leaf and Hyundai Ioniq Electric (6,6 kW), VW e-Golf, Hyundai Kauai EV and Kia e-Niro (7,2 kW), plus Jaguar I-Pace and Mercedes EQC (7,4 kW).

The fastest: BMW i3, Audi e-tron and Tesla Model 3 (11 kW), Tesla Model S and X (17 kW), plus Renault Zoe and Smart EQ (22 kW).

Higher charging safety

The advantages of having a wallbox don’t sit solely on the speed of charge. Another great benefit relates to safety; in fact this type of charger ensures protection against electric discharges, avoiding tension peaks during the charging process in order to stabilize the current’s power.

By doing that, a wallbox protects the vehicles’ batteries and avoids malfunctions resulting from energy peaks in the network. You might have experienced that already!

Deciding to invest in a wallbox means you are also investing in the safety of your electric installation, given that the common power sockets and cables were not designed to supply 2.3 kW for long periods of time.

In sum, with a wallbox you can prevent the vehicle’s electric system from overheating.

Two types of cables

All wall chargers, or wallboxes, come with a Type 1 cable (SAE J1772) or Type 2 (Mennekes) that can be connected to the vehicle directly.

The Type 1 cable, also known as “Yazaki”, is normally used in countries such as Japan and EUA and comes with electric vehicles with the likes of Nissan Leaf, Nissan e-NV200, Mitsubishi i-Miev, Citroën C-Zero, Peugeot i-On, Renault Kangoo ZE (tipo 1), Ford Focus elétrico or Kia Soul EV. It also comes with plug-in vehicles such as Mitsubishi Outlander, Toyota Prius Plug-in or the Opel Ampera which is an EV with an autonomy extender.

This connection is composed of 5 pins: Single Phase, Neutral, Protective (Earth), Input detector and Control Pilot.

The Type 2 cable, commonly called “Mennekes” (standard IEC 62196-2), it’s the most indicated for Europe. It’s three phase, up to 44 kW (63A p/phase), it’s used by Daimler (Smart and Mercedes-Benz) and Renault models (Kangoo ZE and Zoe), for example. Other vehicles that also use this cable type are: BMW i3/i8, Tesla Model 3/S/X, Volvo’s hybrid plug-in, VW GTE’s models, VW e-Up, Audi A3 e-tron and Porsche Panamera E-Hybrid.

This connection is composed of 7 pins: Three Phase, Neutral, Protective (Earth), Input detector and Control Pilot.

The higher the power supplied by the wallbox, the higher its price will be. That means that you might need to consider the different payment options offered by the wallbox seller. Some even offer the option to rent the equipment, paying a monthly fee. Walboxes range from very basic to very smart.

When it comes to intelligence, you have two types of wall chargers:

The Plug & Charge boxes are the most basic ones. As the name suggests, the battery starts charging as the driver starts the car. To stop charging, you only need to disconnect the cable. The vehicle’s charging status is indicated by some LED lights on the charger.

Then we have the smart wallboxes (the type of charger and its functionalities vary) that allow for a dynamic power control and that connect to a smartphone app with its integrated WiFi functionality.

Choosing an Electricity Plan

If you charge your electric vehicle at home, it’s better to do it overnight to take advantage of the time of the day where the energy supply cost is lower – in the case you have chosen a bi-hourly plan.

If you are thinking about buying a wallbox, you should definitely opt for a bi-hourly plan or a three-hourly plan (with cheaper time brackets, normally at night and weekends). In order to choose which one works best for you we advise you to research your options and, if necessary, consult with a specialist in this topic.

Wallboxes are also an intelligent choice precisely because they allow you the comfort of choosing the cheapest time brackets and manage your expenses; not to mention the option to manage your charging sessions remotely (in the case of more advanced wallbox models).

Installing your wallbox: Requirements, a Portuguese company that sells EV chargers, sums up the main requirements to install your wallbox:

  • Ensure that the contracted power is sufficient for the correct functioning of the charging station to the desired charging speed;
  • Check that there is a possibility of adding electrical equipment to the current electrical panel (differential and circuit breaker);
  • Ensure that the electrical panel meets the safety standards of DGEG (Directorate-General for Energy and Geology).

Ensuring you have contracted enough power

Another aspect that must be taken into account before purchasing a wallbox is to ensure that the contracted power is sufficient for the correct functioning of the wallbox at the ideal charging speed.

The higher the contracted power, the simpler the charging, since a reduced power available in your home will leave you with little room for maneuver to have other equipment connected at the same time.

“The greater the contracted power, the more freedom there will be in the vehicle's loading speed", underline the experts at

Every case is different, of course, but note that powers below 4.6 kVa do not allow the wallboxes to function properly. “A contracted power of 10.35 kVA, on the other hand, will support 7.4 kW loads, with a margin for other equipment connected to the electrical installation,” says

Regarding the type of energy meter, single-phase or three-phase, “both are compatible with charging speeds up to 7.4 kW. Above that loading speed, 11 kW, 16.5 kW or 22 kW, are only possible with three-phase meters. To charge your vehicle at 22 kW, it is necessary to increase the power to 20.7 kVA ”, say the experts at

However, to make a better choice between the available range (3.45 kVa, 4.6 kVa, 6.75 kVa, 6.9 kVa or 10.35 kVa) it is always advisable to request an energy audit.

In addition, the entire process of advising and installing the wallboxes will also have to be carried out by qualified technicians who are responsible for adapting the charging station to the charging power of the electrical installation.

With good advice and appropriate choices, you can opt for a charging solution that allows you to fully enjoy your electric car, making the best use of the potential that your EV has to offer and optimizing the energy you are paying for.

► With electric cars growing in popularity, the number and type of these wall chargers also increases – more and more we see different companies offering different models on the market;

► Both, car brands and electricity suppliers, provide these EV chargers and also consultancy services to support the driver in choosing the best charging solution.

► is one of those companies. They offer equipment that allows charging from 3.7 kW to 22 kW, that is, it allows you to “top up” a battery with 75 kWh in approximately 3 hours and 30 minutes.

These are three examples of wallboxes you can find at

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EO Charging


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EO Charging


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Green'Up Access

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Artigo escrito por: Watts On