‘Smart’ devices are becoming an increasing presence in all aspects of our everyday lives. They are designed to save us time, money, and in the world of energy - optimise our resources. We have put together a guide that covers everything you need to know about smart EV charging, in particular:
- What it is;
- How it works and the different modes; and
- How it can benefit you.
Smart EV charging refers to the use of various hardware and software technologies that facilitate load management in EV chargers (typically level 2). This guide will focus on smart chargers using ‘behind-the-meter’ configurations i.e. set by the home/business.
In the future, smart electric vehicle chargers will: communicate with the grid and be controlled by your electricity provider (along with other chargers) to provide stability to the electricity grid. Smart chargers will also feature bidirectional charging (V2G, V2H, V2L) however this is still a few years away from being commercially available. You can read more about how smart ev chargers can provide grid services in Origin’s Smart Charging Trial.
What is a smart EV charger?
A smart EV charger features intelligent hardware and software that enables it to automate and control the charging of your electric car. Known as load management, the charger dynamically adjusts the power sent to your electric car based on preset configurations. It does this by reading the electric signals from various devices and managing and controlling the power flowing from your charger.
What this means is you can simply ‘set and forget’, with the peace of mind that your electric car will be charged the way you want it to without manual intervention.
A smart EV charger comprises:
- Charging unit - A box that houses the intelligent hardware and software required for smart EV charging. It is generally attached to a charging cable.
- Wired/Wifi/Bluetooth connection - Data connection that allows the user to communicate with the charger, typically with an app.
- Smartphone app - All smart chargers are accompanied with a phone app that communicates with the charger and preset configurations.
Due to their higher power output, smart EV chargers typically fall within the ‘level 2’ category.
How does a smart EV charger work?
Smart electric vehicle chargers share real-time data with multiple devices (car, solar inverter and switchboard) to automate charging based on your preferred configurations. Additional equipment such as power meters may be required to unlock the full suite of services smart chargers are capable of.
Today’s smart EV chargers work in three main ways:
1. Scheduled charging
In its simplest form, you can set the timeframe in which you want your charging to occur. For example, it is common for people to limit the charging window to off-peak times to take advantage of lower electricity rates. You could also set the times to align with the hours when your solar system is generating the most energy. The chart below shows charging commencing at 10 pm and ending at 6 am (if needed) when the electricity rate is at its cheapest.
The standard portable charger that comes with your electric car does not typically include scheduled charging as a feature. In the absence of your electric car having this feature, you would need to wait until 10 pm to plug the charger in to ensure you benefit from off-peak rates. Smart EV chargers automates this process for you.
A popular charger that features scheduled charging is the Tesla Wall Connector. While manufactured by Tesla, the charger is also compatible with most non-Tesla electric car models.
The financial benefit of scheduled charging is highlighted in the table below. By limiting the charging window from 10 pm to 6 am (off-peak times), the driver reduces their charging costs by 74 per cent compared to charging at peak times. Over five years, this could add up to $5,545, which will likely exceed the cost of the smart charger.
If your electricity plan is on a flat tariff (same rate irrespective of the time of day), scheduled charging will not provide any financial benefit.
Some electric car models have scheduled charging functionality built into the car's software. This means you schedule your charging even with basic level 1 and 2 chargers (no smart functionality). For example, the Hyundai Kona and Kia Niro are two popular EV models with this feature.
2. Smart solar charging
The ability to charge your electric car from solar is one of the things that make electric cars truly revolutionary. Charging from purely solar means:
- The marginal cost of charging your electric car is almost zero; and
- The operation of your electric car is essentially zero-emission, a true zecar.
Solar charging stations like the very popular zappi have the ability to ensure your electric car is only charged from solar. The charger communicates with your solar system and dynamically adjusts the charge rate based on the available generation of the solar system. Instead of exporting excess solar to the grid, it is diverted the available energy to charge your electric car. This will minimise your draw from the grid.
Smart solar chargers are beneficial in the following situations:
- The rated power of your charger is higher than your solar system; and
- When solar generation is intermittent.
In these instances, your smart charger calibrates its rated power (e.g. 7 kW) to what the solar system is generating (e.g. 3 kW). This ensures that you are harnessing the cleanest energy in the cheapest way possible.
To illustrate the benefit of smart solar charging, we’ve compared a smart EV charger and a standard level 2 charger. The standard EV charger does not dynamically adjust, resulting in only 35% of the solar being utilised over two days. The smart solar electric car charger adjusts the charge rate in line with available solar, maximising solar generation and providing financial and environmental benefits.
3. Load balancing
Electric cars and Level 2 chargers can draw a lot of power from your home/business. Depending on your electrical wiring, the simultaneous operation of charging your car and home appliances could cause your power to trip.
The reason why this occurs is due to the aggregate load from your devices/appliances being greater than what your electrical switchboard can handle. Most grid-connected homes in Australia run on a single-phase 240V power supply and are limited to a maximum power draw of between 12 kW/50A to 20kW/80A. As demonstrated in the example below, you can see that if all the devices were switched on, it would cause a circuit overload and result in your power cutting out.
Similar to solar charging, the smart EV charger communicates with the circuits in your house and detects what the available load is. It then dynamically adjusts the power of the charger to ensure this limit is not exceeded and thus preventing a power trip.
The load balancing feature enables your charger to be used up to its maximum output and adjusts when demand is high in order to avoid tripping and causing a blackout. This means that you can have peace of mind that your home’s power is being protected by your smart EV charger.
What are the benefits of a smart EV charger?
The primary benefit of smart EV chargers is the convenience it provides in terms of time and ‘energy’ saved from speed and automation.
- Level 2 chargers (including smart) are anywhere between 50% (3.6 kW) to 900% (22kW) faster than charging from a standard 10A power outlet (2.4 kW). The actual charging speed however is limited by the power of the onboard charger in the car. For example the onboard charger in the MG ZS EV supports a maximum AC charge rate of 7 kW.
- Charging can be scheduled to your requirements e.g. solar generation, off-peak tariffs without the need for you to manually plug your charger in and out.
Saves money in the long run
- You will save money on your electricity bill by maximising your solar consumption and scheduling your charging to off-peak times.
- The thing to keep in mind is you are often paying a premium for this feature so you will need to weigh up the upfront cost of the purchase versus the saving in the long run.
- By purely charging your electric car with solar, you are minimising your carbon footprint. Above is a comparison of the carbon emissions of different fuels sources. As the Australian grid is still predominantly powered by fossil fuels, the environmental benefit is significant.
- In the future, you will be able to configure your charger to sync with times of maximum renewable energy generation on the grid. This also coincides when energy is at its lowest rate in the wholesale markets.
Smart EV chargers of the future
Two emerging areas we’ll look at in the future are:
Load management with energy provider
Several smart EV Charger pilot projects are currently being undertaken whereby the load of your EV charger will be dynamically adjusted to accommodate requirements of the grid. As EV’s become more popular, this type of smart EV charger will start becoming a standardised service. As of the time of writing, Endeavour Energy is providing a complimentary smart EV charger valued at $3000 to participate in its smart electric vehicle charging trial.
Smart charging features such as bidirectional charging (V2G, V2H, V2L) are becoming a key feature in smart EV chargers of the future. Saying this, we are still several years away before they start becoming a presence in the marketplace. You can read more about how this future looks in our feature guide “Watt is bidirectional charging, V2G, V2H, V2L?”
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