Solar Powered Prius
The next breakthrough in hybrids will likely come from plug-in hybrid vehicle (PHEV) technology. Plug-ins allow the vehicle owner to rechar...
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https://iskablogs.blogspot.com/2007/05/solar-powered-prius.html
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In the meantime, there is a company called Solar Electrical Vehicles (SEV) which may give your Prius an additional boost today. Located in Westlake Village, CA, the SEV system recharges the battery in your hybrid via solar panels installed on the roof the hybrid vehicle.
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It takes 2 to 3 hours to install the custom molded low profile solar module, supplemental battery pack and the charge controlling system. The solar module is designed to last 30 years and it's maintenance free.
The SEV system costs between $2,000 and $4,000. Kits are available for the Prius, Highlander, Ford Escape Hybrid and Toyota Rav4 EV.
Source: San Fernando Business Journal (subscription required) via Treehugger