Fairfax County, Virginia is joining in with other municipalities like the city of Berkeley, California
and adding plug-in hybrids to their vehicle
fleet. Fairfax already has some conventional hybrids
in use and last week, they took delivery of their first plug-in model. The new Prius was converted by Hymotion
of Toronto, Canada
. The stock Prius uses a NiMH battery pack, and Hymotion adds a 5 kWh lithium ion battery. The full factory powertrain is left intact, but the electrical storage capacity is increased by a factor of seven. Even with the integrated smart charger and control electronics, the new extra battery pack is smaller than the factory unit. According to Hymotion, the Prius battery can provide 50 miles of electric only range. The batteries are charged by both the internal combustion engine and regenerative braking while in motion, and also gets juice from the grid when the car is parked. Hymotion claims that the plug-in Prius can achieve more than 100 mpg in combined city/highway driving.