If you’re thinking about getting solar to power your home and your electric vehicle, you’re probably wondering: How much solar and battery storage do I actually need to charge my car at home?
It’s a fair question. And once you add up home usage, night-time charging, and maybe even a second EV in the future, it’s easy to feel overwhelmed.
At PSC, we give you real numbers so you can make the best decision for your unique energy needs and goals. You’ll get some in this article, along with how you can pair an EV with solar.
In this article, you’ll learn about the following:
- How Much Energy Does an EV Actually Use?
- How Much Does It Cost to Charge an EV?
- How Big Does Your Solar System Need to Be to Charge an EV?
- What If You Charge Your EV at Night?
- Real Example: Charging from Solar on the Weekend
- Free Download: EV Charging and Solar Sizing Guide
By the end, you’ll understand exactly what to plan for and how to make the most of solar power to drive your EV further, cheaper, and smarter.
How Much Energy Does an EV Actually Use?
Let’s start with the car. In this case, the example used is a Tesla Model S Performance. It has a 100kWh battery and gets about 500 km on a full charge in real-world conditions. We’re also going to use this example because the math is easy.
Forget the brochure range of 600 km. Real-life driving, whether it’s highway or city, averages out to around 500 km per charge. That means this car uses about 20kWh for every 100 km of driving.
This number is key. The ratio between kilowatt hours and kilometres scales up or down to your needs.
It lets you determine how much energy your EV will use based on your driving habits. Drive 50 km a day? You’ll need about 10kWh. Drive 100 km? You’ll need about 20kWh.
If you’re interested in learning a bit more about the Tesla Wall Connector, you might want to check out the following article titled, Tesla Car Charger Review: Is It Right for You?
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How Much Does It Cost to Charge an EV?
If you charge your EV from the grid at full retail price (around $0.38 per kWh in 2025), a full charge of 100kWh will cost you about $38.
That gets you 500 km of range. Compare that to a petrol car that might cost double or triple to go the same distance. Even if you pay full retail for the electricity, EVs are still much cheaper.
But if you charge using solar, that cost can drop near zero.
If you’re interested in learning a bit more about public charging stations, you might want to check out the following article titled, Electric Vehicle (EV) Charging Guide 2024.
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How Big Does Your Solar System Need to Be to Charge an EV?
To charge your EV at home using solar, you need to size your system based on two things:
- How much energy your home uses.
- How much energy your car needs.
If you already have a solar system sized for your home – let’s say 11.5kW – you’ll need to add another 5 to 6kW just to cover your EV’s needs. That means your total solar system should be somewhere between 16 and 20kW.
Here’s how that works:
- A 20kW solar system in Australia can produce around 78kWh per day (based on 3.9 average peak sun hours).
- That gives you enough energy to power your home and deliver the 20kWh or more your EV might need for daily driving.
This setup works best if you charge during the day while the sun is out. But what if you can’t?
If you’re interested in learning about other EV charger options, you might want to check out the following article titled, Zappi Charger Review: Is It the Right Choice for You?
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What If You Charge Your EV at Night?
Many people drive to work and come home after sunset. If you want to charge your EV at night, you’ll need a battery to store that solar energy during the day.
Let’s say you need 20kWh to charge your EV overnight. Then you’ll need at least 20kWh of battery storage. And that’s just for the car.
You’ll need more storage if you also want your home to run on solar at night. Two Tesla Powerwall 3s (with 27kWh capacity total) would give you the breathing room you need.
This setup lets you charge your EV after hours, run your home on solar at night, and avoid expensive peak-time grid rates.
If you’re interested in learning a bit more about bidirectional EV charging, you might want to check out the following article titled, Bidirectional EV Charging in Australia Explained: Your Guide to V2G, V2H, and V2L.
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Real Example: Charging from Solar on the Weekend
At a home in Kurmond, NSW, one EV owner had a 30kW solar system and Tesla Powerwalls. His daily commute was about 25 km, so he didn’t need to charge during the week. Instead, he topped up the car on weekends.
Here’s how he made it work:
- He set the charger to start at 8:00 a.m. and run all day.
- He reduced the charge rate to 10kW so the solar could run the house and fill the batteries.
- He avoided drawing power from the grid and kept battery cycling low.
This system lets him add 60kWh to the car in a day, while also keeping the house powered and the Powerwalls topped up.
When a second EV came into the picture, they had to repeat the process on Sunday. They used both weekend days to charge their cars while carefully managing solar production.
Multi-EV homes have higher energy demands. It’s not just double the kWh – you also need more flexibility and smarter planning.
Some families, like the one in the Kurmond example, planned weekend charging routines. Others may need to invest in bigger solar systems (25–30kW) and multiple batteries to handle the load.
Workplace charging can also help ease the pressure.
Some employers are starting to offer free EV charging during the day. For example:
- Westmead Children’s Hospital has installed 70 EV chargers for staff.
- PSC Energy allows staff to charge EVs for free using their solar-powered system.
If you can charge your EV at work using solar, you can reduce the size of your home solar system and may not need as much battery storage.
If you’re interested in learning a bit more about the importance of a good installer for your solar (the most important component of any system, seriously), you might want to check out the following article titled, In-house Installers vs. Subcontractors: Which is Better?
Let’s go solar today. Click here.
Free Download: EV Charging and Solar Sizing Guide
To make all of this even easier, there’s a free PDF guide you can download. It includes:
- The top 20 EV models on the Australian market
- How many kilometres each one drives per charge
- How much energy each car needs and how long it takes to charge
- How much solar and battery storage you’ll need based on your usage
This guide was built after quoting dozens of systems and creating the same calculations again and again. It’s now a straightforward tool you can use to size your setup the right way.
Final Thoughts
Charging your EV at home with solar makes sense. It’s cheaper, more sustainable, and gives you complete control over your energy. But it takes proper planning.
To get it right, you need to:
- Know how much energy your EV uses
- Add the right amount of solar on top of your home’s needs
- Store that energy in batteries if you charge at night
At PSC, we know that with the right system, you can power your car and home from the sun. The goal is Net Zero by 2025, so we can all leave the petrol station behind for good.
If you’re interested in learning a bit more about solar batteries, you might want to start with the following article titled, Adding a Battery to a Solar System.
