If you own an EV — or you're considering one — solar panels can dramatically reduce your running costs. Charging from rooftop solar costs roughly 3–5c per kilometre, compared to 10–15c/km from the grid and 15–20c/km for petrol. Here's how to size your system, choose a charger, and maximise solar-powered driving.
How Much Solar Do You Need for an EV?
The average Australian drives about 15,000 km per year. Most EVs consume 15–20 kWh per 100 km, so you need roughly 2,250–3,000 kWh per year just for the car. That's the equivalent of about 2kW of extra solar capacity in most of Australia. So if a 6.6kW system covers your household, step up to an 8–10kW system to comfortably add EV charging. If you already have solar and want to add an EV, check whether your existing system has spare capacity during the day.
Home Charger Options
Level 1 (standard wall plug, 2.3kW) is slow but free — good for overnight top-ups. Level 2 (dedicated wall charger, 7–22kW) is the sweet spot for home use: adds 40–100 km of range per hour. Popular brands include Zappi (solar-aware, adjusts to surplus), Tesla Wall Connector, and Ocular. Budget $1,000–$2,500 installed for a quality Level 2 charger. The Zappi deserves a special mention because it can automatically adjust charging speed to match your available solar surplus — maximising free solar charging.
Solar Charging Economics
At 17 kWh per 100 km and 30c/kWh grid electricity, driving 15,000 km costs about $765/year from the grid. With solar (effectively free), that drops to near zero. Even if you charge 50% from solar and 50% from grid, you save ~$380/year on fuel alone. Compare this to petrol: a comparable ICE car at 8L/100km and $2/L costs $2,400/year. Switching from petrol to solar-charged EV saves $1,600–$2,400 per year.
Best Setup for Solar EV Charging
The ideal setup is a 10kW+ solar system, a Zappi or similar solar-aware charger, and the habit of plugging in when you get home from work (before sunset in summer, or anytime if you have a battery). A battery isn't essential for EV charging but helps: it stores daytime solar for evening charging when you can't plug in during the day. Some newer EVs support bidirectional charging (V2G/V2H), potentially turning your car's battery into home storage — watch this space.