EV Charging With Solar: How To Maximize Your Solar Investment

Using the sun’s energy and power to charge your electric vehicle (EV) is the ultimate option for reducing operational costs associated with charging. Still, there are additional ways to maximize your solar investment.

Key Takeaways:

1️⃣ Pay less tax with the Federal EV Tax credit for buying an EV and installing a home charger.

2️⃣ Get further tax credits when you install a PV system in your home or business.

3️⃣ Invest in bidirectional charging so your electric car can power your home.

4️⃣ Utilize an EV solar inverter with integrated vehicle charging to maximize value.

Each of these key elements will now be expanded on, starting with solar panels. Let’s dive in!

Understanding Solar EV Charging

As the sunlight hits them, solar panels use tiny photovoltaic cells to create a stream of electrons or an electric current.

This is the DC electricity that runs to store energy in the batteries. This DC is converted into AC for use in your home or business.

Most solar panels are about 22% efficient, meaning they can only use about 22% of the sun’s energy to create electricity.

The quantity of power created will depend on the number of peak sun hours during the day, which is location-dependent. For example, states in the south will have more sunlight than states in the north.

EV chargers use AC from the solar inverter to charge the DC battery. To bridge this gap, the car uses an onboard converter to transform the AC into DC. This converted DC is then stored in the battery until it’s needed to power the vehicle.

The main challenge with using solar is on days when sunlight isn’t optimal. UV will still be available for the panels on cloudy days, but they will generate less power than on full sun days.

The risk here is that your PV system batteries don’t have enough capacity to charge your electric car and run the home, so you may be at a public charging station to top up your EV battery.

Maximizing Your Solar Investment For EV Charging

If you consider a complete solution (buying an EV and solar installation at your home or office), several federal tax incentives will reduce your cost and improve the ROI.

The Federal Tax Credits For EVs, Chargers, And PV Systems

The first one is the EV tax credit which gives you a maximum once-off non-refundable tax credit of $7500 on a new EV with a maximum value of $55,000 or an SUV/Van/Pickup with a maximum value of $80,000- for a used EV, that tax credit is $4000.

Secondly, a tax credit of up to $1000 or 30% for the EV charging system you install at home and a 30% tax credit for costs and components associated with installing a home solar system.

💡Related Articles:
The EV Tax Credit Explained
Things To Know About The EV Charger Tax Credit

Considering that the average cost of a 5kW system is between $15 000 and $20 000, this would be a saving of around $4500 to $6000 on the installation, added to the $7500 credit for an EV and the $1000 for the charger – that’s about $13 000!

Invest In Bidirectional Charging 

This is one of the most exciting technological developments in EV charging. While certain infrastructure challenges must be overcome before this can be rolled out on a grander scale, the potential is massive for EV owners and the energy industry.

Bidirectional charging allows EVs to become portable power banks and use their fully charged batteries to power homes, businesses, mobile devices, and others.  

Considering that an average EV battery has a capacity of around 65kWh and the average home uses around 30kWh daily, a fully charged EV battery could power your home for TWO days!

We know that the cost of recharging an EV compared to fuel costs is much lower, so using your EV as a power source significantly improves your ROI and optimizes your investment when recharging with solar.

Not counting the initial capital outlay, your EV chargers from your solar panels or rooftop system cost you nothing, so you now have enough power to run your EV or your home for free.

This will significantly lower your monthly energy bills and even allow you to supply power back into the grid with net metering- where you receive credit from the utility company for energy sent back to the grid.

As more manufacturers include bidirectional charging with their EVs and major strides are made to standardize communication protocols and connectors, this technology will be the default option in the near future.

💡 Related Article: An Introduction to Vehicle-to-Grid Systems

Maximize Your Solar Investment With Integrated Solar EV Chargers 

The current configuration for a home rooftop PV system is solar panels generate electricity from sunlight and convert that to AC for storage and distribution throughout the home.

The EV would plug into level 1 or 2 chargers and utilize the AC power delivered from the inverter to charge the battery.

With an integrated solar EV charger, this device would act the same as a conventional inverter. But the smart charger charges using available solar energy and takes advantage of lower tariffs to reduce costs.

Considerations For Solar Charging At Home

You can only use the 120V level 1 charger or the 240V level 2 charger for home charging. Level 1 charging plugs into a conventional 120V AC socket and is the slowest charging option as the kW output varies between 1,4kW and 3,6kW.

Level 2 chargers have a capacity between 7kW and 22kW, typically the wall box type chargers available. Depending on the battery size, this will charge an EV from flat to 100% in about 5-6 hours, while a level 1 charger would take around 30 hours or more to charge a BEV from empty to full.

Remember, though, that if you have an existing PV system, you need to ensure that you have enough capacity to add a level 2 charger, or you risk depleting your stored power- but if you can charge your EV during the day, then you can save the cost of additional capacity.

If you only need solar for your EV, then a dedicated roof-mounted solar EV charger would be a good option too. Depending on the EVs battery capacity, this charger would need a solar array of between 6 and 12 panels.

Best Practices For Charging EV With Solar

If you can get an inverter with a solar-only charging function or a dedicated solar EV charger, this is the optimum for charging your EV using solar. 

You could also opt for an integrated inverter that has an EV charging port and would also work as a PV system inverter for your home or business.

Another good option is to charge your EV during peak sun hours to reduce the charging time or overnight when the grid demand is low, and the tariffs are lower.

How To Maintain Your Solar EV Charger 

  • Use the correct gauge cables to ensure optimum current flow and charging time.
  • Check the connectors periodically and remove any corrosion or buildup on the terminals.
  • Keep the solar panels clean and free from dirt and debris to maintain maximum generation.
  • Monitor the solar charger’s display to know when the battery is full and how much power is generated and drawn.
  • Use a professional, accredited installer when installing your solar EV charger.

If you find your solar EV charger is not working for any reason or the EV is taking longer to charge than usual, you can:

  • Check the display for charging errors. 
  • Check that the charging connector is securely locked in the EV charging port.
  • Check the solar panels are clean and that the connections are solid.
  • Most chargers come with diagnostics on their apps, allowing you to troubleshoot and resolve potential problems.

Key Takeaways 

The key elements to remember about using solar charging over grid power car charging are summarized below: 

1️⃣ You can charge your vehicle with solar and enjoy the benefits of tax credits for the EV, charger, and solar panels.

2️⃣ This is a clean, cost-effective way to recharge your EV and is cheaper than grid power.

3️⃣ You can use level 1 and 2 chargers, but level 2 will be faster.

4️⃣ Invest in bidirectional charging to use your EV battery to power your home or business if needed.

5️⃣ Dedicated solar EV chargers or inverters that have integrated vehicle charging are a better option.

Using solar power to charge your EV takes demand and pressure off the grid and reduces carbon emissions from electricity production.

Installing solar panels in your home is a great way to save money and reduce taxes, especially if you live in an area with lots of sunlight. You can even install a dedicated EV charger that uses solar energy to charge your car.

Solar isn’t only limited to residential or commercial situations. Learn more about the ever-improving portable solar chargers for electric cars and their use cases.