Charging your EV with solar in New Zealand

Why charge an EV from solar

When your panels generate more than the house is using, that surplus is normally exported for a buyback rate of around 12c/kWh. But grid power costs roughly 33c/kWh (and is rising). So if you use that surplus to charge your EV instead of exporting it, every unit is worth two to three times more. Charging from your own solar is the cheapest way to run an electric car.

What it costs to run

Running costs from Consumer NZ (Oct 2024). Light EVs also pay Road User Charges of about $76 per 1,000 km (≈7.6c/km) since April 2024 — include this when comparing to petrol.

How much solar does an EV need?

An EV uses roughly 15–18 kWh per 100 km. At the NZ average of about 11,500 km a year, that's around 2,000 kWh of extra electricity — so installers typically suggest adding about 2–3 kW of solar to broadly offset EV charging over a year. The right amount depends on your driving and how much you can charge in daylight, so it's best modelled by an installer. Try our savings calculator to size a system.

Smart (solar-diversion) charging

A standard home charger and a Level 2 wallbox typically cost about $1,500–$2,500 installed. "Solar-diversion" or "eco mode" smart chargers go a step further — they automatically charge the car from your surplus solar, ramping up and down to soak up excess generation rather than exporting it cheaply. NZ solar installers now commonly bundle an EV charger with a solar install, so it's one electrician visit, one cable run and one set of paperwork.

Does an EV change my solar system size?

Yes — an EV is a significant new load, so an EV household usually wants a larger array (commonly around 2–3 kW more than a base home system, which is often about 6.6 kW) and a smart charger to capture daytime surplus. There's no fixed number; it depends on your driving distance, roof space and charging habits.

Frequently asked questions