Charging an electric car

Today we can charge an electric car (EV) in many ways. The fastest way is to charge at public stations with direct current, the network of which is constantly expanding. The most common power in our region for DC charging stations is 50 kW. Tesla electric cars

so-called Superchargers with an output of up to 120 kW can be recharged, and station manufacturers already present DC charging stations with an output of up to 350 kW. It is also necessary to take into account the higher cost of DC charging. AC charging stations can also be used in the public sector, where charging power of up to 22 kW can be used. However, for most EV owners in the private sector, AC charging at home will be the most common, using a wallbox/EV charger.

Several charging options can also be used in domestic conditions, differing in particular in terms of charging speed and safety. The easiest way to charge is from a classic domestic 230V (SCHUKO) socket, using the cable that is normally supplied with the electric car. However, this method is limited by a maximum output of 3.7 kW. Another option is recharging from a three-phase socket, where it is possible to reach a higher charging power, depending on the circuit breaker (16 – 32A), but just like with a single-phase socket, there is a limitation in fuse protection, safety, the ability to regulate charging and other shortcomings.

The most suitable way in home conditions is to charge EVs using a so-called wallbox/EV charger. The Wallbox is connected to existing distribution systems in the building and has its own protection. Modern wallboxes are equipped with a so-called current sensor to ensure optimal charging according to consumption. They can also include DC leakage detection, detect the cross-section of the charging cable, prevent house circuit breakers from tripping and adapt charging accordingly. Wallboxes are also used in the public and commercial spheres, which is why there are a large number of variants on offer. The most important manufacturers include Fronius, Solax, Keba and SolarEdge, which you can also find in our product range.

When choosing the right wallbox, you need to determine several basic parameters:

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• When choosing the right wallbox, you need to determine several basic parameters:
• Power - varies from 3.7kW up to 22kW depending on one or three phase connection and circuit breaker (16, 32A). For home use, it is also necessary to take into account the integrated charger in the electric car, which limits the maximum charging power. Most often it ranges up to 11kW. For the public sector, it is more appropriate to choose the 22kW variant. The price differences are not large and the increased variability will be appreciated by owners of e.g. Renault Zoe or Tesla Model S with the possibility of recharging up to 22kW AC.
• Residential/commercial/public sphere - the basic distinction will be the area of ​​use of the wallbox. Compared to domestic use, the public/commercial sphere requires more additional functions. In simpler terms, it can be: the number of sockets (up to 2 for 1 wallbox), the possibility of connecting multiple wallboxes and controlling the charging of multiple EVs at the same time (slave/master) – load management system, identification using RFID or a key, the possibility of payment, a certified electricity meter, increased resistance to environmental influences, the OCPP (Open Charge Point Protocol) interface for obtaining accounting data about charging, or extended communication with the wallbox.
• Socket or cable - For home or company charging of the fleet, it is more appropriate to choose an option with an integrated cable, for maximum simplification of the charging process. For public wall boxes, the version with a socket is recommended. The main reasons are mainly the lifetime of the system (vandalism, wear...).
• Connector – another important aspect is also to choose a suitable type of connector. Today, the standard for EU countries is TYPE 2 connectors (Mennekes) - AC charging, CCS2 for DC charging. However, it is still possible to meet TYPE 1 and CCS1 connectors for DC charging, which are used mainly in Japan and the USA.
• Mounting method – on a column or on a wall.
• Charging function from excess photovoltaics (PV).

Connection of PV and EV

A very interesting function in the home environment is the use of excess energy from the own photovoltaic power plant. It is this connection that makes a lot of sense for many EV mobility enthusiasts and photovoltaic owners. Moreover, the experience of PV and EV owners shows that even lower charging power from home PV can be sufficient and bring many benefits. Regardless of the ecological benefit, this combination is of particular economic importance. Surpluses from the PV system can be used in such a way that energy is provided to appliances in the home and instead of returning the surpluses to the grid, the electric car is charged. In order to use excess PV for charging, it is necessary to acquire a wallbox with such a function.

ro, one of the largest manufacturers of inverters came up with a solution for the simplest possible connection of photovoltaics and electromobility. SolarEdge offers the world's first combination of inverter and EV-charger in one device. It can be purchased as an EV-charger with a power of 3.68 kW. It is a solution more suitable for residential use. Via the mobile application, the device can be set to charge the electric car according to individual charging modes. These are chosen by the user based on current requirements (charging speed, charging time, and charging source – PV/grid).

Charging methods using a wallbox

• The use of PV for charging an electric car from a wallbox can generally be divided into several stages, or charging modes, taking into account the type of inverter and wallbox. These are the following degrees:
• Plug n Charge – the easiest way to charge. Whenever the electric car is connected to the wallbox, it is charged, regardless of whether there is surplus PV or not. This option is the least effective, but the cheapest.
• Controlled charging - or also planned charging. Another of the world's inverter manufacturers is entering the market at this charging level. The company Solax comes with the first generation of its own wall boxes. The first generation will be able to communicate with its own current sensor (CT) to control charging from excess PV. Additional functions are communication via the OCPP protocol, RFID authorization.
• Charging can be controlled using time planning, i.e. charging is set for a time when the tariff is cheaper, or for a time when there are usually surpluses from PV. Planned charging cannot adapt the charging power exactly according to current surpluses. It is charged according to the maximum currently available energy. In the event of a lack of PV energy, energy is also supplied from the grid. Nevertheless, this variant is significantly more efficient than plug'n'charge and at the same time is not too expensive.
• Dynamically controlled charging – The most effective solution for using surpluses from PV is dynamically controlled charging (dynamic control). Charging adapts to current surpluses and it is possible to use only PV energy (ECO/GREEN mode). In addition, charging is always adapted to the current household consumption. At the same time, thanks to local load management (LLM), it is possible to control several wallboxes and thus efficiently allocate energy when charging several electric cars at the same time. For all mentioned uses of wallboxes, including LLM, there is a wide range of models from the renowned Austrian manufacturer KEBA, with decades of experience in the field of EV charging. Charging from solar energy does not have to be limited only to the time of energy generation, but with hybrid PV systems it is also possible to use excess energy stored in battery storage and charge from solar energy, e.g. at night. Intelligent charging is possible thanks to integration into Smart home and the use of Smart energy management.
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• Boost mode - or fast mode is used for maximum charging speed. The Wallbox manages the charging so that it does not take into account the source (mains/PV), but tries to charge as fast as possible. It is also possible to combine both energy sources at the same time. With a wallbox from SolarEdge, using this function means up to 25% faster charging than with another wallbox with the same performance.
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For more information, contact us at GBC Solino s.r.o., where specialists will be happy to answer your further questions or help you configure your PV system - obchod@gbc-solino.cz