Imagine having an electric vehicle that generates its own power, and you never to plug in? That dream is out of reach for most of us. But most of us don’t have degrees from UC Berkeley and MIT as well as a resume that includes Senior Staff Engineer at Samsung.

Meet Omid Sadeghpour, an engineer who built a portable solar array for his Tesla Model Y. His clever design stows away on the car’s roof rack until he parks. He’s seen it add up to 75 miles of range in a day, but says it consistently gives his EV 20 miles of range. He expects version two will achieve twice the range.

Here’s the nuts and bolts: Sadeghpour’s design is nine separate solar panels attached to Tesla’s factory roof rack. He found that regular metal supports would be too heavy, so he built a wood frame and custom telescoping carbon fiber poles so the panels can slide into place.

This first version (which Sadeghpour calls Beta 1) is rated for 1,575 watts. With its bulky wooden frame it sits 11 inches high, so causes a fair amount of aerodynamic drag. But Sadeghpour is already hard at work on Beta 2. He is targeting 4,000 watts and a height of just five inches. In addition, he is building a custom roof rack designed for better aerodynamics. But even Beta 1 may be saving his Tesla a ton of energy–even when the car is parked!

In hot weather, the Tesla Model Y cycles its HVAC to keep the cabin from getting boiling hot. This draws some power from the traction battery. But the canopy of solar panels help shelter the car from the sun.

On Reddit, Sadeghpour said, “The car is cooler on hot days for sure. The panels do absorb a loot of heat. It’s always hot to the touch. (SIC)” He hopes to test Beta 1 next to a Model Y without a solar array to establish exactly how much energy the canopy is preserving.

For Beta 2, Sadeghpour is not just re-engineering the roof rack that holds the panels. He is upgrading to a 4,000 watt solar array. He hopes this will reliably generate 45 miles of range every day. And if that number doesn’t sound high to you, know that Kelley Blue Book reports the average American drives just 37 miles per day. For most Tesla Model Y owners, a Beta 2 solar array would mean they only need to plug in to a charger on a long road trip.

Here’s the kicker: Sadeghpour thinks a company could build these things for about $4,000! At that price, they’d pay for themselves quick, and allow you to top off at work even if there’s no charger.

Obviously, certain folks just need more range on the daily. Other drivers live in places with cloudier climates and might not see that full 45 miles every day. But Sadeghpour is proving that large solar arrays on every car could go a long way toward meeting our country’s energy needs.

Personally, I’m excited to see the first round of overland EVs with solar arrays that can off-road indefinitely. But that’s another story.

You can stay up-to-date with Beta 2’s progress on Sadeghpour’s website: Dart Solar, or see him describe his design process in the video below: