A fitting charging solution for every situation

Electric mobility will soon be the new normal. Over the past few weeks, we’ve been hearing this more and more frequently from the management of car manufacturers such as Volkswagen. Almost all manufacturers offer at least one electric car in their line up these days. The transition to electric is coming — that much is certain. It won’t be immediate, but projections unanimously tell us that, by 2025, a good quarter of all new cars will be powered by an electric motor.

To make electric mobility a sustainable reality, the transition to electric drives and to sustainable energy sources will need to be achieved simultaneously. A move away from fossil fuels, as well as the development of renewable energies, will of course be of central importance to this. Efficient use of the existing infrastructures is also key. This is especially important when multiple electric cars need to be charged at the same time.

In most cases, charging multiple electric cars simultaneously without additional controls would overload the local grid connection. A load management system, which generally makes sense for three or more cars, can remedy the situation. It controls the charging process, thus avoiding both high costs of expanding the grid connection and increased annual service fees due to high peak loads. There are various intelligent systems of this type available to meet specific needs.

Double charger: the classic solution for private properties and small businesses

A double charger is a good solution for anyone with only two electric cars to charge. It consists of a standard wallbox, but with two charging connectors. These double chargers are typically designed with 22 kW charging power and cost around 3,930 euro. When only one car is being charged, it gets full power from the power grid. If both cars are plugged into the wallbox, the power is shared between both charging stations and 11 kW are available for each battery — which is sufficient to fully charge even a large battery overnight or during a working day.

Master-slave charging solution for smaller fleets

Anyone needing to charge between 3 and approx. 15 cars simultaneously should consider a master-slave system — as long as the cars are all from the same manufacturer or need only one type of charging station. These systems are available from manufacturers such as ABL, KEBE, and Mennekes, among others. In this arrangement, the master wallbox serves as the central control unit, taking over the load management for the slave charging stations. It divides the available energy evenly across all charging stations that currently have an electric car plugged in. These types of systems are available for 1,300 euro gross for the master wallbox, plus an additional 1,150 euro for each slave wallbox.

Many electric cars and a limited grid connection: a charging and energy management system

If multiple electric cars need to be charged, the user needs flexibility as to the choice of charging station type and manufacturer. There is also the question of whether additional interfaces to the PV or building management system are needed. For this situation, charging and energy management systems are available, such as the ones from the technology company The Mobility House. This type of system is a particularly good choice for companies starting off with a small number of charging stations, e.g. property developers, or larger businesses. The advantage of this system is that it can be scaled as desired; it can accommodate dozens of wallboxes and charging stations from different manufacturers. It is also possible to assign “VIP charging stations” that receive preferential treatment.

To ensure that the grid connection is used as efficiently as possible and no unbalanced loads occur, the charging stations feature a phase-inverted connection. This solution is available from The Mobility House starting at 1,150 euro per wallbox plus a one-time investment of 1,899 euro for the charging and energy management system.

Intelligent systems have the really big picture in mind

All three of the previously mentioned systems are permanently integrated into the grid environment. That means that only the previously defined maximum power limit is available to charge the electric cars. Dynamic load management systems (e.g. the one from The Mobility House) are even more efficient. They take into account the energy needs of the other building occupants and/or the grid environment in the immediate surroundings. This means that, at night, when hardly anyone else is using power, more energy is available to charge the electric cars

Optimal charging of multiple electric cars with fluctuating building loads

For network connections where the building’s energy load fluctuates, such as residential buildings and industrial businesses, dynamic charging and energy management systems can be a good option. These represent the pinnacle of efficient use of the grid environment. They use the building’s current load to calculate the maximum available charging power in real time, adjusting the flow of current to the charging stations as needed. The dynamic system from The Mobility House can not only be scaled flexibly to include various AC and DC charging infrastructures; it also offers the ability to prioritise individual charging stations — VIP treatment — as well as phase-inverted connection optimisation.

The cost savings are immense. A charging park with 25 charging stations, operated without dynamic load management, for example, would incur a one-time expense of more than 30,000 euro for expansion of the grid connection, plus an additional 15,000 euro per year in increased service fees as a result of the higher peak loads. This means that anyone wishing to charge electric cars cost-effectively is well advised to use intelligent, managed charging.