Technology group Solatec LLC claims to have developed a solar panel that can improve the fuel efficiency performance of hybrid cars by 10%.

The company said it has introduced flexible, rooftop-mounted solar panels for hybrid vehicles, starting with a kit for the 2004-2006 Toyota Prius. The US$2,195 kits will be available across the US through dealer franchises.

The company claims that a prototype has been operating in the Northeast for several months under mixed driving conditions. In a statement it said that with Solatec panels installed on the roof, the prototype SolaPrius averages 55 MPG city and 62 MPG highway - an overall 10% improvement over the pre-installation numbers. All-season testing is in progress.

Solatec's photovoltaic kit adds two flexible, conformal panels that charge the hybrid automobile's auxiliary battery through a proprietary charger/current-limiter system concealed behind interior trim panels. The self-adhesive, rooftop-mounted panels are only 0.6mm thick and cause no change in aerodynamic drag, Solatec said.

Development of the hybrid vehicle solar panels came about as a side project of Solatec LLC's solar aircraft research, which uses the same high efficiency flexible photovoltaic panels to sustain the aircraft in flight. The same aircraft grade adhesive is used on both systems.

Kits for other hybrid cars are presently in development and testing.