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Technical terms for
e-mobility – simply explained


The transformation to electromobility is accompanied by many rather technical terms and abbreviations. But what is actually behind it? voylt clarifies:

What is behind the unit Volt (V)

According to the international system of units, volt is the unit for electrical voltage. It was named after the Italian inventor and physicist Alessandro Volta. In electromobility, volt is primarily used in reference to a vehicle's system voltage. The rule of thumb applies: more helps more!

Higher voltages allow higher charging speeds, which in turn enable higher charging performance. However, you will only benefit from these higher voltages and charging powers if you also have an appropriate oneCharging station find. Because if the charging station only charges at a low voltage, the vehicle and therefore you unfortunately do not benefit from the shorter charging time. As always, it's best to find out in advance what characteristics your vehicle has so that you don't end up annoyed. By the way: The household socket in Germany usually has 230 volts. The most modern electric cars these days have a system voltage of up to 900 volts, so a lot more!

In addition, higher voltages also allow thinner and therefore lighter cables to be installed, which reduce the weight of the vehicle and thus theRange of the vehicle. More volts means faster charging and a longer range. If that's not a win-win situation...

What is a kilowatt?

The unit kilowatt (kW) stands for power. This unit was also named after a physicist. Namely the Scotsman James Watts. In relation to electromobility, this unit is usually used as “kilowatt” (kW), although the unit itself is actually just watt (W). Ultimately, one kilowatt simply corresponds to 1,000 watts, because the word “kilo” originally comes from the Greek (chílioi) and means “thousand”. Similar to the units known as kilometers or kilograms.

In electromobility, the unit watt is mostly used to refer to two things:

  • The engine power of the vehicle

  • The charging capacity of the vehicle

The same applies here again: more helps more! So if your vehicle can charge with many watts or even kilowatts, you can look forward to shorter charging times! Of course, you first have to find a suitable charging station. Especially the fast chargers or alsoHPC(High Power Charger) are so far less common in Germany. A charging cable is required for these charging stationsCCS standardused. However, your vehicle's battery charges just as well with fewer watts at the household socket or on AC chargers with fewer kilowatts of charging power.

In general, you can travel faster with a lot of motor power. The more powerful your engine, the faster the acceleration will normally be, which is generally not a bad thing with electric vehicles.

By the way: kW is also the “correct” unit for the performance of a combustion engine and is therefore also used in vehicles with diesel or gasoline engines.

What is a kilowatt hour?

Now it gets a little more abstract. A watt hour describes the energy over one hour. Kilo again only means that it is 1000 watt hours. Similar to the units known as kilometers or kilograms. The word “kilo” originally comes from the Greek (chílioi) and means “thousand”.

Known from the electricity bill, for example, this unit is mainly used in electromobility for the energy of a vehicle battery, or how much energy theBatteries can save. Unfortunately, this time it is not so easy to standardize that more is better. A huge battery that can store many kilowatt hours of energy generally has a longer range, but is also significantly heavier. And more weight is of course bad for the range and, above all, the overall efficiency of the vehicle. It is therefore best to always look at the ratio between range and kilowatt hour in order to assess how good or efficient the vehicle actually is. A good guideline here is “kilometers per kWh”. The more kilometers a vehicle can squeeze out of a kilowatt hour, so to speak, the higher the overall efficiency of the vehicle.

The unit GWh (gigawatt hour) or TWh (terrawatt hour) is often used for electricity storage and battery factories. A GWh is a million kWh and a TWh is another thousand GWh. So a lot of energy.

Ampere - basic unit of electrical current

Ampere is the basic electrical unit of current. Ampere therefore refers to the amount of electrons or charge carriers that flow through a line in a certain period of time. The unit of measurement for ampere is the 'A'; the current unit ampere was named after the French physicist and mathematician André-Marie Ampère. He researched the connections between electricity and magnetism and developed devices for measuring electricity.

The current strength can be calculated using current power and voltage by dividing the power by the voltage. So the formula for calculating amps is: amps = watts/volts

What is a Newton meter?

A newton meter is the SI unit for the vector quantity torque (torsion). In addition, 1 N m = 1 joule, the unit of the scalar quantity energy, heat and work. Two fundamentally different things, torque and energy, are calculated using Newton times meters. TheTorqueindicates how strong a force acts on a rotatable body. For electric vehicles, this is reflected in the acceleration strength or theclimbing abilitynoticeable. The torque is measured in Newton meters (Nm), i.e. a force of 100 Newton acts on a two meter long lever, for example, a torque of 200 Nm is produced.

What is climbing ability?

The climbing ability of a vehicle refers to the ability to climb an incline. The climbing ability depends on several factors: engine power, engine gear ratio, vehicle drive concept, weight distribution, center of gravity of the vehicle, traction of the tires on the ground. The climbing ability depends, among other things, on the wattage of the electric motor. The more power it has, the better the electric vehicle pulls. Realistically speaking, a 350 watt motor can handle gradients of around 10%. Information of up to 15% is a lot for an electric scooter. 

Rated power or maximum power?

The rated power, often also called “rated continuous power”, “continuous power” or “nominal power”, refers to the highest continuous power at which an energy technology device can be operated without affecting its service life and safety. The nominal power is binding for the entire service life of the system.

The maximum performance is the peak performance of a system. However, the rated continuous power is therefore naturally lower. For advertising purposes, it is therefore more attractive to indicate the maximum performance, i.e. the higher value.


The “Association for Own Consumption” (ZEV) has enabled owners of functional and residential buildings to provide self-generated electricity for their own consumption since January 1, 2018. A ZEV is connected to the public power grid. ZEV operators must determine consumption using private meters and bill users. In addition to the daily electricity consumption for households, this can also be used for electromobility.


By the way, ZEV is an abbreviation that has another meaning:Zero emission vehicle – a vehicle that does not emit harmful emissions. 

About the store:

AC and DC charging

AC - Alternating Current and translated means alternating current. Alternating current flows from wall boxes, the Schuko socket and most public charging points. This is converted into direct current by the electric vehicle's on-board charger. This conversion is important because the built-in car battery can only store direct current. 

DC charging stations convert the alternating current (AC) from the power network into direct current (DC) directly within the station. This bypasses the mains converter inside the car and the direct current flows directly from the station into the car battery. This charging process enables higher charging performance in a shorter time. Such fast charging stations are primarily suitable for locations with short dwell times, i.e. at motorway service areas or supermarket parking lots.

On-board charger

The on-board charger is an internal charger that converts the AC voltage (alternating current) from the socket into the required DC voltage (direct current) according to the requirements of the battery management system (BMS) and then forwards it to the battery for storage. During the charging process, the charger monitors other charging-related parameters. In general, the on-board charger is only used when charging at a charging station or wallbox in the AC network with up to 22 kW. With an on-board charger, the charging process takes around 6 to 8 hours. If the charging station is a DC charging solution, a quick charge process takes around 40 minutes, the charging station establishes a direct connection to the vehicle's high-voltage battery. The on-board charger is automatically bypassed by the BMS because direct current is already present.

Bidirectional charging

With bidirectional charging, electricity can flow in two directions: first from the grid into a storage device (e.g. a car battery) - and then out of it again, back into the grid. Bidirectional charging includes the areas of Vehicle to Grid (V2G), Vehicle to Home (V2H), and Vehicle to Load (V2L). Each of these use cases requires different framework conditions.


  • Vehicle to Grid (V2G): Ime-car There is a normal Schuko socket to which you can connect electrical devices on the go. 

  • Vehicle to Home (V2H): This to theWallbox Connected electric car delivers energy to your household's power grid. 

  • Vehicle to Load (V2L): The e-car feeds the energy in thebattery stored electricity not only into the domestic grid, but even into the entire public grid.

The technology for bi-directional charging already exists and some electric car models have this capability. 

In April 2023, the International Organization for Standardization published ISO 15118-20, which regulates communication between e-cars and charging devices, such as a wallbox.

Inductive charging

Many people are familiar with the possibility of inductive charging from their smartphones or other electronic devices, where you no longer need an extra charging cable, but simply place the device on an induction surface. 

This technology should also be possible in electric cars in the future. Researchers at the University of Erlangen-Nuremberg have initiated a pilot project on inductive charging. By 2025, a one-kilometer-long test track will be built on a section of motorway in northern Bavaria on which inductive charging of electric cars and trucks will be possible. This allows the vehicles to be charged wirelessly while driving. Coils are built into the road surface that generate a magnetic field. This magnetic field generates voltage in the counter coil installed in the vehicle, which can be used to transmit power. This constantly changing magnetic field allows energy to be transferred and converted into electricity. The road recognizes exactly where the car is and only transmits the electricity there. Data can also be transmitted over the road - so it can later be determined who has filled up with electricity and how much electricity.

Charging infrastructure

Charging infrastructure is the entirety of charging facilities. In addition to the charging point or charging column/wallbox, this also includes the transformer station, cable systems and other technical ancillary equipment. A charging point within the meaning of the charging station regulation (LSV) is a facility suitable for charging electric vehicles and where only one electric vehicle can be charged at a time.

Publicly accessible charging points for electric vehicles must meet minimum technical requirements. In order to be able to check compliance with these requirements in accordance with the Charging Station Ordinance, operators are obliged to report their publicly accessible charging infrastructure to the Federal Network Agency. Reported charging points can be published on the charging station map with the consent of the operator.

The Federal Network Agency's charging station register contains 93,261 normal charging points and 22,047 fast charging points that were in operation on november 1, 2023. A total of 3.98 GW of charging power can be provided at the charging points at the same time.

Current figures and overview maps of the charging infrastructure in Germany are available atFederal Network Agency


Payment at public charging stations is usually made using charging cards from various providers or their apps. As a rule, a vehicle owner can get by with three different options. More and more charging stations now also offer payment by credit card if you don't have the right charging card at hand. That's what it's called"ad hoc loading."

Certain charging providers offer a convenient service for cars that have an appropriate system setting:Plug & Batch (PnC). This is a new standard (ISO 15118) that simplifies communication between the e-car and the charging station. To start the charging process, you simply need to connect the vehicle to the charging station using the charging plug. The registration then takes place automatically - no charging card, no start button - the charging process starts automatically and is billed directly to the connected customer account after completion. 

Range extenders

As range extenders, additional units are used in a Electric vehicle refers to the Range of the vehicle. As a rule, a small combustion engine is used for this, which takes on the role of a generator and in this way supplies the battery and motor with electricity, essentially having its own small power plant on board. This range extender acts as a backup and thus works the Range anxiety contrary.

But there is also another accessory variant that is particularly popular in the two-wheeler sector. This is an upgrade in battery performance, often made possible by an additional battery.

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