E-car charging times: The most important questions and answers
1. What factors influence the charging time of e-cars?
How long it takes to charge an electric car depends primarily on two factors: the capacity of the battery and the performance of the charging station. The battery capacity can be compared to the volume of a fuel tank and indicates in kilowatt hours (kWh) how much electricity the battery can store. The larger the battery, the longer it takes to charge. The charging station power corresponds – figuratively speaking – to the pressure at which a conventional petrol station can pump fuel into the tank. The higher the values, the faster the loading. In addition, there are other factors that influence the charging time:
- The current charge level of the battery not only determines how much electricity needs to be charged in the first place. If the battery level is less than 20 percent and more than 80 percent, the on-board electronics also throttle the charging speed to save the battery. This means that charging very empty or very full batteries takes disproportionately longer than charging at medium charge.
- The on-board voltage determines the amount of electricity the electric car can process and how quickly. For example, the maximum applicable voltage is limited, especially in many older vehicles. Modern e-cars, on the other hand, can also take advantage of the high performance of fast-charging stations thanks to their efficient on-board charging systems.
- Lithium batteries, which are usually installed in electric cars, do not like particularly high or particularly low ambient temperatures. At unfavorable temperatures, the batteries charge much slower than at temperatures between 15 and 25 degrees Celsius.
2. How do you calculate the charging time of electric cars?
Manufacturers usually specify the average charging times in the technical documentation for the respective model. However, the factors mentioned above influence the specific charging time. This makes general statements difficult. Approximately the charging time can be calculated using this simple rule of thumb:
Battery capacity (in kWh) : Charging power (in kW) x 1.3 = charging time (in hours)
The factor of 1.3 stands for the fact that the charging power can fluctuate during the charging process due to the many factors.
3. What are the charging times for electric cars?
4. What is the fastest way to charge your car?
The German power grid is mainly operated with alternating current (AC). E-car batteries, on the other hand, are based on direct current (DC). Therefore, the current must be rectified at one point. When charging at AC stations, which usually offer between 11 and 22 kW of power, the alternating current is converted into direct current by the built-in rectifier of the electric car. This allows a battery to be charged in around two to six hours, depending on the capacity.
DC charging stations, on the other hand, do the reclamping themselves. They can provide 50 kW and more of power, which can then be fed into the electric car battery without further conversion. The charging time is significantly shorter at 30 to 60 minutes.
Learn more about the different types of charging stations in our guide.
5. How long does a 50 kW electric car charge?
The so-called fast charging stations with direct current have an output of 50 kW and more – which usually allows an electric car to be charged to 80 percent in less than an hour.
6. Which cars can be charged with 22 kW?
More and more modern e-cars have internal chargers (on-board chargers) that are designed for 22 kW. They therefore require only about half the charging time of vehicles with chargers for 11 kW and can be charged in around two to four hours. Private wallboxes are usually available with a maximum charging power of either 11 or 22 kW. Most conventional public e-charging stations that are not fast-charging stations are equipped with two Type 2 plugs, which also offer 22 kW AC power.
Good to know: Up-to-date information about the Promotion of private charging stations can be found in our guide.
7. What are the requirements for fast charging, and what are the advantages and disadvantages?
The fast-charging network (DC) is being successively expanded, and more and more DC charging stations can be found, especially on motorways and expressways. But not all e-cars are suitable for this. For example, the vehicle must provide technical support for fast charging and, of course, be equipped with an appropriate plug – either with the CCS plug ("Combined Charging System") or with the CHAdeMO plug, which is still used by some older Asian cars.
Charging the battery quickly has advantages and disadvantages. Thanks to the short charging times, it is particularly suitable for long-distance journeys when you don't want to spend more than a coffee break at the charging station on the road. However, a higher tariff is usually due for fast charging. And: Frequent fast charging leads to higher wear and tear on the battery, as its cells are subjected to a lot of stress. If fast charging is not absolutely necessary, you can charge with less power. This saves the battery.
8. What is the difference between charging at a household socket and at a wallbox?
It is true that an e-car can be charged at a standard household Schuko socket. However, this should only be done in emergencies. Not only can this type of charging take a lot of time with eight to 14 hours, because only 3.6 kW of power is available. It can also push a normal household socket to its load limit, which can result in a short circuit, spark jump or even a fire.
A wallbox for the home is therefore the better choice. This allows e-cars to be charged in your own garage or at the parking space in the underground car park in two to six hours, depending on the available power. Ideally, the Wallbox with a photovoltaic system and thus powered by solar power from your own roof. This reduces costs and is particularly climate-friendly.
9. How often should you charge an electric car to 100 percent?
Extreme charge levels should be avoided as much as possible, i.e. the battery should not be run to zero percent empty or charged to 100 percent. The reason: Both damage the lithium-ion cells in the long run. Ideally, the charge level should always be between 20 and 80 percent. If you fully charge the battery before a long-distance trip in order to exploit the full range, you should start the journey as soon as possible in order to lower the charge level again as soon as possible.