How does an EV charger connect to a home with solar?
An EV charger connects to the home's main electrical system like any other load, and it draws from solar production first and the utility grid for the rest. The solar system does not need a separate charger circuit, but the panel must have capacity.
Solar panels feed power into the house through an inverter, and the home panel distributes it. The charger circuit is a normal breaker in the panel, so the home uses solar production when it is available and grid power when it is not. Because the charger sits on its own breaker, nothing about it changes how the solar system produces power or how the inverter works. Ask your solar installer if you have questions.
The electrician checks how the solar system ties into the panel, because the way the system connects to the busbar can limit where breakers can go. That detail sometimes shapes the plan more than the charger itself does. Tell the electrician where the solar breaker sits so the plan is clear. Share your inverter details. Share your inverter details and the age of the system.
Does my solar system affect the load calculation?
Yes, the solar system affects the panel's capacity limits. The electrician considers the main breaker, the solar breaker and the busbar rating, along with your existing loads. Solar does not automatically make the panel bigger, so a load calculation is still required.
Many Arizona homes with solar also have older panels with limited space. Adding a charger can push the panel past what the code allows, even when the solar system produces plenty of power. A load calculation looks at the main breaker and the busbar together, and the solar breaker counts as a source that connects to the same bus, so it limits what else can be added there.
If capacity is tight, options include load management, a subpanel, a panel upgrade or a service upgrade. Your solar installer may also need to be involved if the panel is changed, so the electrician coordinates the work to protect the system. Ask your solar installer for the system documents before the site visit. Ask for the model numbers too. Ask for them soon.
Should I charge during the day to use my solar power?
Charging during the day uses solar production directly, but it only helps if your car is home then. Many Arizona utility plans reward overnight charging at lower time of use rates, so the best schedule depends on your solar plan, your driving habits and your utility terms.
Rules vary by utility and by when your solar system was installed. Check current terms with APS or SRP for how exported power is credited and how time of use rates apply to your plan. Time of use plans generally favor off peak hours, and solar exports may be credited differently depending on your plan, so ask the utility how the credit works before choosing a schedule.
If you work from home or the car stays in the garage during the day, daytime charging may suit your system well. If you commute, overnight charging may be the practical choice. A smart charger can follow a schedule either way. Whichever you choose, the charger circuit is the same, and you can change the schedule in the app. Try both for a month.
Can a home battery work with an EV charger?
A home battery can work with an EV charger, but the charger is a large continuous load that can drain a battery quickly. The electrician and the battery installer should plan together so the battery, the panel and the charger are sized to match.
Some owners limit charging while on battery backup, and some systems manage it automatically. The charger may be placed on the main side of the panel, not on the backed up loads, depending on the design. Backup loads are usually on a protected subpanel sized for the battery, and a large EV charger can overwhelm it, so the design should decide this before the circuit is run.
Any panel changes need a permit, and the solar or battery installer may need to approve changes to their equipment. Contact us for a written quote, and share your system documents so we can plan around them. Bring the documents, photos and model numbers to the first visit so the plan is accurate from the start. Ask your utility. Ask them soon.
Need an EV Charger Installed?
Vortech installs Level 2 home chargers across Phoenix, Glendale, Peoria, Sun City, Sun City West and Surprise. See EV charger installation or read the full guide on this topic.
More questions: Home EV Charger Installation: 12 Most Asked Questions Answered