California-based Solar Electrical Vehicles (SEV) has created a unique option for the Prius electric hybrid. The kit consists of a convex solar-panel made from high efficiency mono-crystalline photovoltaic cells, with modules rated at 200-300 watts. The power is used to charge a 3kW secondary battery that can be used to drive the vehicle up to 20 miles per day on electric power alone.

With fuel economy improved by around 29%, depending on driving style, owners could recuperate most of the $2000-$4000 cost of installing the system within 2 to 3 years. Performance can also be improved further with the addition of higher-capacity batteries that are currently in development, potentially adding another 10 miles of electric-only drive.

“All the technology is there,” said SEV president Greg Johanson in a recent interview with the San Fernando Business Journal. “It’s just the larger manufacturer taking the next step,” he added. The company is now looking at developing similar systems for the Toyota Highlander Hybrid and even the Tesla Roadster.