Solar Batteries for EV Charging Australia: Charge Free Overnight

Solar Batteries & Electric Vehicles (EVs): How to Charge Your Car for Free Overnight

Electric Vehicles (EVs) are growing rapidly across Australia. However, plug-in charging from the grid during peak evening tariff hours (38c–44c/kWh) can significantly erase your expected fuel savings.

By pairing a home solar battery with a smart EV charger, you can store daytime rooftop solar energy and transfer it into your electric vehicle overnight—allowing you to drive thousands of kilometers per year on 100% free solar power.

The Math: Driving 15,000 km/yr on Stored Sunshine

• Daily Commute Energy (40 km/day): Requires 6.0 kWh of energy per day.

• Cost charging from peak grid (38c/kWh): $2.28 / day = $832 / year.

• Cost charging from stored solar battery power: $0.00 / day = $0 / year.

• Annual Savings vs Petrol Car ($2.00/L): $2,550 / year saved.

Recommended System Specs for Solar + Storage + EV

Ideal Solar + Storage + EV System Package                             

• Solar Panel Array:   8.8 kW to 10 kW High-Efficiency Panels     

• Home Battery Capacity:   13.5 kWh Usable Storage (Tesla / Sigenergy) 

• Smart EV Charger:   7.4 kW Single-Phase (Solar Interlocking)    

• Estimated Annual Savings:    ~$2,400 to $2,800 / year 

Vehicle-to-Grid (V2G) & Vehicle-to-Home (V2H) Readiness

Next-generation smart energy hubs (such as the Sigenergy SigenStor) feature bidirectional V2G and V2H hardware capability. Your EV's 60kWh+ battery pack can act as a massive backup power reservoir for your home during multi-day grid blackouts.