The first is the potential for power overload in the family. Residential power depends on diversity. In other words, you can’t turn on all your devices at once. Few people have a 10kW shower for an hour that simultaneously has an electric oven, washing machine, hair dryer, etc. This situation changes with the plug-in electric vehicle, where it can consume up to 7kW of electricity continuously for more than ten hours. The base load of electric vehicles, showers and other electrical appliances of 10kW can seriously exceed the service and interrupt current of 23kW (100 A).
The second problem is that the grid also relies on diversity. This means not showering, cooking and heating at the same time. Connecting two long-draining 7kW EV chargers can overload the power grid and local substations. This increase in power demand comes at a time when it is becoming more difficult to have the capacity to meet peak demand. With fewer coal-fired power plants and more intermittent renewable, grid operators need more tools to manage demand. Energy management is the real reason behind the move by governments to promote smart chargers for electric vehicles.
In addition, smart charging allows the energy stored in EV batteries to be used to meet spikes in grid demand. It is estimated that a conventional 22kW EV charging station takes 6-7 hours to charge an EV battery. With a 50kW fast charger, the time to fully charge the battery is less than 1 hour. Since home and work are the most common places where EV drivers connect their vehicles to charging stations, we know that EVs are left connected longer than necessary.
With smart charging, your car will stay connected and only charge when it is most efficient from a cost perspective and from the grid (low demand charging is grid friendly).