Is your Prius properly pumped? In the grand old tradition of exacting more performance from one's vehicles, some enterprising hybrid owners are adding battery packs with plug-in leads to maximize the time the car runs on its electric motors. For example, electrical engineer Roy Gamban of San Francisco (where else?) has added eighteen cells to his Prius, which he charges via roof-mounted solar cells at his home. When the auxiliary batteries are discharged after about 20 miles, the car flips back to normal hybrid operation, giving him an average of around 96 mpg.
Hot Rod Heirs Customise Cars to Give 300mpg [Telegraph, UK]
Supercapacitors to Offer Hybrid Energy Boost? [Internal]