Charging electric vehicles
We charge with an AC charger (using alternating current) or in other words we charge at home or at work. This option is the easiest and least complicated, but also the slowest and “kindest” method for your battery life. Home charging can be performed using standard household plugs (230 V) or using a three-phase socket of the type CEE(400V).
The charging speed depends on:
– the type of charger and charging cable used
– the specification (parameters) of your car’s on-board charger
– the specification (parameters) of the electricity mains that you have available at home or work.
The maximum possible charging speed is thus dependent on the max. load through the socket (mains supply) and the performance of your car’s on-board charger. In general we have three socket types.
- Type Schuko – 1 phase max. 3.7 kW
- Type CEE 16 A – 3 phase –max. 11 kW
- Type CEE 32 A – 3 phase –max. 22 kW
From the given values we know that the fastest possible charging is achieved with a socket type CEE 32 A/3 phase in combination with an AC charging station (Wallbox) or “FastCable” rated to handle a voltage of 3 x 230V and maximum current of 32 A.
For a standard electric vehicle the charging time from a 230V socket will be roughly 10 to 12 hours to full charge. Using a 3- CEE (400V) socket we can speed up the process by around a factor of ten. During this method of charging the car makes use of its own integrated charger. Its parameters and settings determine the charging speed. Using the socket type CEE (400V) makes maximum use of the charging potential of domestic electricity supply.
How do you select the most suitable combination for achieving the most effective charging of your car? The first pointer should be information on the mains electricity supply that you have available. 32A 3-phase? single-phase? Or 16A 3-phase? And make a decision according to this. The second pointer is the specification of the on-board charger. If, for example, your car is fitted with just a 3.7 kW on-board charger then it doesn’t matter whether you charge using a single-phase 230V socket or via an AC station 32A/3-phase/22 kW. The on-board charger will not permit a greater charging power than 3.7 kW.
- Charging from a 230V single-phase socket – we can use, for example, this EV cable with control unit
- Charging through a “Wallbox”. We select a Wallbox able to make maximum use of the given mains electricity supply (16A/3-phase or 32A/3-phase) even in a case where the existing electric vehicle is unable to make full use of the available power. A good-quality Wallbox lasts a long time and the on-board chargers on new electric vehicles will have improved performance. Once you have bought an electric car you are sure to buy another. When topping up at night, and other times when the cost of electricity is significantly cheaper, this is the most cost-effective option.
- Charging using a “FastCable”. This option combines the characteristics of a charging cable and Wallbox. This “FastCable” is actually a kind of mobile Wallbox that is able, with the correct set up and input conditions, to provide the same charging power as a fixed Wallbox of similar specification. The advantage of this solution is that the cable can be transported in your car so you always have it to hand.
The use of public fast DC charging stations (using direct current)
In this type of charging, the car battery is connected directly without using the on-board charger for alternating current. However, here too the limiting parameter is what power is supported for fast DC charging. Across the Czech Republic and Europe we can find public stations of large distributors as well as private stations. The power of these stations varies between 20 kW and 350 kW. Thanks to these power ratings the charging time is significantly decreased. Each owner of DC charging stations has its own regulations for using them. Sometimes it is possible to use them free of charge, whilst for others a prepaid card or chip is necessary. Most of these stations are equipped with the required charging cable. Nevertheless, it is necessary for each car to carry the correct connecting EV cable.