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Do I Make Enough Solar Power to Charge My EV? Calculator
Checked and updated by our licensed electricians: October 2026
Do you make enough solar power to charge your electric car? Five quick taps (how far you drive, when the car is home, your solar, your power bill, whether you have a battery) and the numbers are on your screen: how many kWh a week the car needs, how much of that your roof can cover, and how much more solar, or whether a battery, would close the gap. Free, honest assumptions shown, no details asked for and no need to talk to anyone to see the result. If you want it, you can then ask us to text you the numbers with our Northern Rivers Battery Buyer’s Guide.
How the estimate is worked out
- The car: 18 kWh per 100 km, a typical real-world figure for Australian EVs (small cars use less, large SUVs more). Your weekly kilometres come from the range you pick.
- Your roof: about 3.8 kWh per kW of panels on an average Northern Rivers day (the Clean Energy Regulator rates our zone at 1.382 MWh per kW a year). Winter days make about 30 per cent less.
- Your house first: about 45 per cent of a household’s use happens in daylight, so that share of your bill’s kWh is taken off the solar before anything goes to the car.
- When the car is home: solar can only go straight into the car while it is plugged in during the day. Home most days counts 80 per cent of the car’s charging as daytime, weekends only 35 per cent, away all day 10 per cent.
- A battery: stores the day’s spare solar for the car at night, up to about 16 kWh a night in the estimate.
Read how a solar-aware charger works in charging your EV from solar and a home battery, and what we install in home EV charger installation.
Why most EV owners end up with more solar, and often a battery
An EV adds roughly a third to a typical household’s electricity use. A 6.6 kW system that covered a home comfortably before the car often falls short once the car is plugged in, especially in winter and especially when the car is away all day and charges at night. Two fixes work: more panels, so the roof makes enough spare in the day, and a home battery, so the day’s solar waits for the car. We design all three together, solar, battery and charger, from your power bills and your driving. See adding more solar panels to an existing system and adding a battery to existing solar.
EV chargers we install
- Sigenergy EV charger for Sigenergy battery systems: charges from spare solar, from the battery or from the grid on a schedule. Sigenergy systems.
- GoodWe HCA for GoodWe ESA systems. GoodWe systems.
- Sungrow AC charger for Sungrow systems.
- myenergi zappi for any other solar, and for homes without solar.
All installed by our own licensed electricians, Tweed Heads to Evans Head and west to Lismore. Work out the rest of the system with our solar and battery price calculator, the battery quiz and the blackout runtime calculator. All our free calculators are on one page.
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Leave your name and mobile. We’ll text you within minutes to size solar, a battery and the right EV charger from your power bill.
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Choosing the car as well? Our EV buyer’s guide for home charging and solar compares every EV sold in Australia in 2026: battery, range, 7 vs 11 vs 22 kW charging, V2L and V2G, and which charger suits your system.
Questions we get asked
How much solar do I need to charge an electric car?
A typical EV uses about 18 kWh per 100 km. If you drive 250 km a week, that is about 45 kWh a week, or 6.5 kWh a day. On an average Northern Rivers day each kW of panels makes about 3.8 kWh, so the car alone needs roughly 1.7 kW of solar if every bit of it went to the car. In practice the house uses solar during the day too, and the car is often away, so most homes need 2 to 4 kW more than they would without the EV. The calculator works it out for your driving and your roof.
Can I charge my EV straight from solar?
Yes, with a solar-aware charger. The Sigenergy EV charger (for Sigenergy systems), the GoodWe HCA (for GoodWe) and the myenergi zappi (for anything else) can charge at whatever your panels are exporting at that moment, so the car soaks up spare solar instead of it going to the grid. The car has to be home in the day for that to work, which is why the calculator asks when the car is home.
Do I need a battery to charge an EV from solar?
Not if the car is home in the day. If the car is away all day and home at night, a home battery is the only way to move solar from the day into the car at night: the panels fill the battery, the battery charges the car. A 16 to 18 kWh battery can hold about a day of driving for most households, as long as the roof makes enough spare solar to fill it.
How many solar panels does it take to charge an EV?
Panels today are about 440 to 470 W each, so 1 kW is a little over two panels. Each kW of panels makes about 3.8 kWh on an average Northern Rivers day. A 250 km a week driver needs roughly 1.7 kW for the car alone, about four panels, before allowing for the house and for winter.
Is it cheaper to charge an EV from solar than from the grid?
Solar you make and use yourself costs you only the feed-in you give up, which is a few cents per kWh with most retailers, so for most homes charging from spare solar is the cheapest way to run the car. We do not promise savings figures: they depend on your tariff, your driving and how often the car is home in the sun.
Do I have to give my details to see the result?
No. The numbers show on the screen as soon as you have answered the five questions, with nothing to fill in. Under the result there is an optional box: add your first name, mobile and postcode and we text you the numbers with a link to our Northern Rivers Battery Buyer’s Guide, plus two times for a free 15-minute phone call about your power bill, your driving and the right charger, which you can take or leave.
Which EV charger do you install?
The Sigenergy charger for Sigenergy systems, the GoodWe HCA for GoodWe systems, the Sungrow AC charger for Sungrow systems and the myenergi zappi for any other solar or homes without solar. All are installed by our own licensed electricians across the Northern Rivers, and all can be set to charge from spare solar. Our head electrician goes through the options and pricing with you on a short call.
