EV Chargers

What is a Smart EV charger?

Electric vehicle chargers are becoming more sophisticated as manufacturers seek to make EV charging more cost-effective for homes and businesses. Smart chargers allow you to automatically charge an EV when electricity prices are low or when solar power is being generated. Standard level-2 chargers draw a lot of power, and smart controls can also help prevent overloading the grid supply. In addition to helping to optimise charging, most smart EV chargers now have Wifi and Bluetooth as standard to enable easy setup and monitoring using a mobile app.

Smart EV charging modes

Smart EV chargers have numerous options to optimise charging, reduce charging costs and increase self-sufficiency using solar. The most common is solar-only charging and charge scheduling using cheap off-peak electricity. Another useful smart charging mode is Load Balancing. The charge rate is dynamically adjusted to ensure the charger doesn’t overload and trip off the electric supply when other high power appliances (loads) are running. This is very important if more than one EV charger is installed or there is limited electricity supply.

Solar Charging

Charging an EV using a home solar system appeals to many people as it dramatically reduces the vehicle’s operating cost and increases self-sufficiency. However, this isn’t easy if you cannot optimise the charging rate to match your solar generation. For example, many level-2 home chargers have a maximum charging rate of 7.4kW. Still, most residential solar inverters are rated at 5 or 6kW, and the amount of solar being generated may be far less, especially during poor weather. Luckily, this is where smart EV chargers can help. Unlike regular EV chargers, which are set at a fixed charge rate, Smart EV chargers can dynamically adjust the charge rate based on solar generation. However, smart chargers require a special CT meter to measure energy flow and enable advanced features such as solar-only charging and load balancing.

Load-balancing

EV chargers use a lot of power which can cause issues for some homes or businesses if it draws too much power from the grid. The load-balancing feature available on some smart chargers is handy for those with a limited grid supply that may trip under high loads. Load balancing controls can enable an EV to charge at the maximum rate, up to 7.4kW on a single-phase supply, when the household consumption is low. However, if the household consumption increases, the EV charge rate will drop automatically and not trip the grid main supply circuit. This is also very useful for homes or businesses with more than one EV charger. It prevents overloading or tripping the main grid supply when multiple EVs are charged simultaneously.

For load-balancing to work, an external energy meter, called a CT meter, is required to measure electricity flow to and from the home or business. Smart chargers use the CT meter data to adjust the charging rate dynamically and optimise charging.

Scheduled charging

To reduce EV charging costs, most smart EV charger chargers can be set to charge when the electricity rates are low. The cheapest (off-peak) rates are generally during the night when most people are sleeping, so a pre-set off-peak charging schedule can automatically charge the EV overnight. Electricity demand is at its highest during the evening, which is also when electricity tariffs are typically very high. EV charging during these periods costs you more and places a more significant strain on the electricity network, which can already be stretched to its limits during extreme heatwaves.