By: Mattias Nilsson, Global sales engineer at Zaptec.
Everyone wants to charge their EV with solar. Few talk about what it actually takes. Here's what I've learned about charging with the sun, even in a "sun-poor" country like Sweden.
As we transition towards a greener world, solar energy has emerged as one of the most promising ways to reduce carbon footprints and promote sustainability. While solar panels are already widely used to power homes, the next frontier is optimising that solar energy for electric vehicle (EV) charging. This is not just a trend. It is a step toward a smarter, more sustainable energy ecosystem.
At the heart of this shift is the goal of using energy more intelligently, reducing electricity costs, and easing reliance on the grid. But achieving that in practice is more complex than simply plugging an EV into a solar-powered system.
Optimising solar energy for EV charging involves navigating real-world limitations. While many homeowners dream of charging their EVs using only the sun, the fluctuating nature of solar production means that, in practice, it’s rarely that straightforward.
A homeowner and EV driver, Zach wants to make the most of his rooftop solar installation. He’d rather use the energy his panels generate than export it to the grid or pull electricity from it. But like many, he’s come up against a few realities.
To begin charging, most EVs require a minimum of 6 amps (6A) of current. Solar panels often don’t produce that consistently —especially on cloudy days or during mornings and evenings. When solar production dips below this threshold, charging can’t start. So even with solar panels producing energy, Zach sometimes misses the opportunity to charge.
On overcast days, Zach would love to avoid paying for electricity entirely. But realistically, solar energy production drops, and charging must draw from the grid to remain active. Solar optimisation isn’t about full disconnection from the grid—it’s about reducing reliance on it where possible, not eliminating it altogether.
Energy consumption is also distributed across three phases in most homes. Even if you're exporting excess energy on one phase, you might be importing on another. In the end, it’s the net sum across all three phases that determines what you pay—or get back.
Zach doesn’t want to micromanage his energy use. He wants a system that “just works”—smart enough to use solar when it’s available, balance what’s needed from the grid, and adapt automatically. But that level of optimisation requires help from third-party energy management systems.
Zaptec charging systems are solar-ready—but true solar optimisation is achieved through integration with third-party systems. By using Zaptec’s open API, these partners can balance solar production with grid consumption, enabling a more intelligent and efficient use of energy. Together, these solutions ensure that when the sun shines, it’s prioritised—and when it doesn’t, the transition is seamless.
When configured properly, Zach’s setup can even turn his EV into a dynamic part of the energy ecosystem. If there’s surplus energy, it can be exported to the grid—sometimes even earning credits or lowering the electricity bill. It's not about isolation from the grid, but participation in a more balanced and responsive energy system.
In the face of the climate crisis, solar optimisation isn’t just convenient—it’s responsible. It's about using the energy we have more wisely. With the right combination of EV charger, solar panels, and smart energy partners, people like Zach can make the most of their investment in renewable energy.
The journey toward smarter charging isn’t about perfection or independence—it’s about progress. At Zaptec, we believe in building flexible, future-ready solutions that embrace complexity but deliver simplicity.
Because when solar optimisation is done right, it’s not just about efficiency—it’s about moving us all closer to a truly sustainable future.
Mattias Nilsson, Global sales engineer at Zaptec, has already charged his car with solar energy for several years.