As the world shifts towards sustainable energy solutions, integrating solar photovoltaic (PV) systems with electric vehicle (EV) chargers is becoming increasingly popular. This integration can be optimised using Current Transformer (CT) clamps, which help manage energy flow and improve efficiency. In this blog post, we’ll explore the benefits and considerations of using CT clamps in solar PV systems and EV chargers, with a focus on intelligent charging solutions like Octopus Intelligent Go.
Understanding CT Clamps in Solar PV Systems
CT clamps are devices that measure the current flowing through a conductor without directly connecting to it. They provide real-time data on energy production and consumption, which is crucial for optimising energy use and ensuring efficient operation. In a solar PV system, CT clamps are used to monitor the flow of electricity from the solar panels to the inverter, battery, and grid.
Key Functions of CT Clamps:
- Monitoring: Track the amount of electricity generated by the solar panels.
- Control: Ensure that excess energy is stored in the battery or sent back to the grid.
- Protection: Help in maintaining safe operation by monitoring current levels and preventing overloads.
Intelligent EV Charging with Octopus Intelligent Go
Octopus Intelligent Go is a smart charging solution that optimises the charging of electric vehicles based on grid demand and electricity prices. It can communicate either with the car’s API or the charger’s API, allowing for efficient and cost-effective charging.
In a nutshell – Here are the key benefits:
- Cheap Night Rates: Every night, electricity costs just 7p per kWh between 23:30 and 05:30.
- Daytime Rate: The daytime rate is 23.59p per kWh. (price dropped in July)
- Smart Charging: When you plug your car in at 7pm (for example), it communicates with Octopus Energy. They often allow you to start charging earlier than 23:30, such as between 7pm and 9pm, and then continue overnight.
- Lower Household Electricity Costs: During these special charging windows, when the car is actively charging, all your household electricity is also charged at the low rate of 7p per kWh. This means if you were using grid power for your home during these times, you’d be charged at 7p rather than 23.59p per kWh.
Addressing Integration Challenges
Integrating an EV charger with a solar PV system can present challenges, particularly with regard to the CT clamps’ placement and the potential for unintended battery discharge. The positioning of CT clamps is critical in this setup. If the inverter’s CT clamp is placed before the EV charger’s CT clamp, the system can misinterpret the load from the EV charger as a household demand, causing the inverter to discharge the battery to meet this demand.
This situation arises because the CT clamp on the inverter detects the current flowing to the EV charger, leading to a potential discharge of the solar battery, which is not ideal for maximising energy efficiency. To avoid this, it’s essential to ensure that the CT clamp on the inverter does not include the load from the EV charger in its readings.
Considerations for System Design:
- Battery Capacity: A typical car battery is around 70kWh, while an inverter battery typically ranges from 5 to 15kWh. Using the inverter battery to charge the car is impractical due to the size difference.
- Household Demand: The average household demand for a day is 10-13kWh, but a car requires 70kWh. It’s more efficient to use the grid during the special charging windows provided by Octopus.
- Cost Efficiency: During the low-rate charging windows (7p per kWh), using grid power is more cost-effective than discharging the solar battery. Additionally, exporting excess solar energy at 15p per kWh is financially advantageous.
Installation Considerations
Steps for Installation:
- Plan the Layout: Determine the placement of CT clamps, inverter, and EV charger.
- Run Data Cables: Use Cat6e cables for communication between CT clamps and the inverter.
- Install EV Ultra Cables: These cables incorporate both power and communication lines, simplifying installation.
- Configure the System: Ensure the CT clamps are correctly positioned to prevent the inverter from detecting the EV charger.
Benefits of Proper Installation:
- Optimised Energy Use: Accurate monitoring and control of energy flow.
- Cost Savings: Lower electricity rates during off-peak hours and optimised charging times.
- Increased Efficiency: Prevents unnecessary battery discharge and maximises the use of solar energy.
Expertise in Solar PV and EV Integration
Blue Electrics are experts in integrating Solar PV systems with intelligent EV charging solutions. They can help customers make informed decisions, ensuring that the setup is optimised for both current and future energy needs. Should circumstances change in the future, the system is flexible enough to allow for adjustments, such as swapping the CT clamps to adapt to new configurations.
Conclusion
Integrating Solar PV systems with CT clamps and intelligent EV chargers like Octopus Intelligent Go can significantly enhance energy efficiency and cost savings for homeowners. By carefully planning the installation and configuration, you can ensure that your system operates seamlessly, providing both environmental and financial benefits.
For those looking to adopt these technologies, consulting with professionals like Blue Electrics and staying informed about the latest solutions is crucial. With the right setup, you can enjoy the benefits of renewable energy and smart charging, contributing to a more sustainable future.
